To create a Layer 2 virtual forwarding instance (VFI) and enter Layer 2 VFI manual configuration mode, use the
l2vfimanual command in global configuration mode. To remove the Layer 2 VFI, use the
no form of this command.
l2vfinamemanual
nol2vfinamemanual
Syntax Description
name
Name of a new or existing Layer 2 VFI .
Command Default
The Layer 2 VFI is not configured.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.2(18)SXF
This command was introduced on the Supervisor Engine 720.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
15.0(1)M
This command was integrated into a release earlier than Cisco IOS Release 15.0(1)M.
Cisco IOS XE Release 3.7S
This command was integrated into Cisco IOS XE Release 3.7S.
Usage Guidelines
A VFI is a collection of data structures used by the data plane, software-based or hardware-based, to forward packets to one or more virtual circuits (VC). It is populated and updated by both the control plane and the data plane and also serves as the data structure interface between the control plane and the data plane.
Within the Layer 2 VFI manual configuration mode, you can configure the following parameters:
VPN ID of a Virtual private LAN service (VPLS) domain
Addresses of other PE routers in this domain
Type of tunnel signaling and encapsulation mechanism for each peer
Within the Layer 2 VFI manual configuration mode, the following commands are available:
This example shows how to create a Layer 2 VFI, enter Layer 2 VFI manual configuration mode, and configure a VPN ID:
Router(config)# l2 vfi vfitest1 manual
Router(config-vfi)# vpn id 303
Related Commands
Command
Description
l2vfipoint-to-point
Establishes a point-to-point Layer 2 VFI between two separate networks.
vpnid
Configures a VPN ID in RFC 2685 format. You can change the value of the VPN ID only after its configuration, and you cannot remove it.
neighbor
Specifies the type of tunnel signaling and encapsulation mechanism for each peer.
l2protocol-tunnel
To enable the protocol tunneling on an interface and specify the type of protocol to be tunneled, use the
l2protocol-tunnel command in global or interface configuration mode. To disable protocol tunneling, use the
no form of this command.
Global Configuration
l2protocol-tunnel
[ coscos-value | global | mac-address ]
nol2protocol-tunnel
Interface Configuration
l2protocol-tunnel
[ cdp | lldp | stp | vtp ]
nol2protocol-tunnel
Syntax Description
cos cos-value
(Optional) Specifies a class of service (CoS) value globally on all ingress Layer 2 protocol tunneling ports.
PortFast BPDU filtering is enabled automatically on tunnel ports.
If you do not specify a protocol, all protocols are tunneled.
You can configure protocol tunneling on VLAN and trunk interfaces.
You must enter the
switchport command once without any keywords to configure the LAN port as a Layer 2 interface before you can enter additional
switchport commands with keywords. This action is required only if you have not entered the
switchport command for the interface.
Examples
This example shows how to enable a tunneling protocol on an interface:
This example shows how to disable a tunneling protocol on an interface:
Router> enable
Router# configure terminal
Router#(config)interface fastEthernet 4/0
Router(config-if)# no l2protocol-tunnel
Protocol tunneling disabled on interface fastEthernet 4/1
Related Commands
Command
Description
showl2protocol-tunnel
Displays the protocols that are tunneled on an interface or on all interfaces.
switchport
Modifies the switching characteristics of the Layer 2-switched interface.
l2protocol-tunnel cos
To specify a class of service (CoS) value globally on all ingress Layer-2 protocol tunneling ports, use the
l2protocol-tunnelcoscommand in global configuration mode. To return to the default , use the
no form of this command.
l2protocol-tunnelcoscos-value
nol2protocol-tunnelcos
Syntax Description
cos-value
CoS value; valid values are from 0 to 7.
Command Default
The
cos-value is
5
Command Modes
Global configuration
Command History
Release
Modification
12.2(14)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
The
cos-value is the CoS value that you assign to the PDUs on a Layer 2-protocol tunnel port before tunneling the PDUs through the service-provider network.
You can specify a CoS value globally on all ingress Layer 2-protocol tunneling ports. Because the CoS value applies to all ingress tunneling ports, all encapsulated PDUs that are sent out by the Cisco 7600 series router have the same CoS value.
On all the service-provider edge switches, you must enable PortFast BPDU filtering on the 802.1Q tunnel ports by entering these commands:
PortFast BPDU filtering is enabled automatically on tunnel ports.
Examples
This example shows how to specify a CoS value on all ingress Layer 2-protocol tunneling ports:
Router(config)# l2protocol-tunnel cos 6
Router(config)#
Related Commands
Command
Description
showl2protocol-tunnel
Displays the protocols that are tunneled on an interface or on all interfaces.
l2protocol-tunnel drop-threshold
To specify the maximum number of packets that can be processed for
the specified protocol on that interface before being dropped, use the
l2protocol-tunneldrop-threshold command in interface configuration
mode. To reset all the threshold values to 0 and disable the drop threshold,
use the
no form of this command.
PortFast BPDU filtering is enabled automatically on tunnel ports.
If you do not specify a protocol, the threshold applies to all
protocols.
You can configure protocol tunneling on switch ports only. You must
enter the
switchport command once without any keywords
to configure the LAN port as a Layer 2 interface before you can enter
additional
switchport commands with keywords. This
action is required only if you have not entered the
switchport command for the interface.
Refer to the “Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol
Tunneling” chapter of the Cisco 7600 Series Router Cisco IOS Software
Configuration Guide for additional information on setting the drop threshold
value.
Enables the protocol tunneling on an interface and
specifies the type of protocol to be tunneled.
l2protocol-tunnelcos
Specifies a CoS value globally on all ingress Layer-2
protocol tunneling ports.
l2protocol-tunnelglobaldrop-threshold
Enables rate limiting at the software level.
l2protocol-tunnelshutdown-threshold
Specifies the maximum number of packets that can be
processed for the specified protocol on that interface in 1 second.
showl2protocol-tunnel
Displays the protocols that are tunneled on an interface or
on all interfaces.
switchport
Modifies the switching characteristics of the Layer
2-switched interface.
l2protocol-tunnel global drop-threshold
To enable rate limiting at the software level, use the
l2protocol-tunnelglobaldrop-threshold command in global configuration
mode. To disable the software rate limiter on the Cisco 7600 series routers,
use the
no form of this command.
l2protocol-tunnelglobaldrop-thresholdthreshold
nol2protocol-tunnelglobaldrop-threshold
Syntax Description
threshold
Maximum rate of incoming PDUs before excessive PDUs are
dropped; valid values are from 100 to 20000 PDUs.
Command Default
Global thresholds are not configured.
Command Modes
Global configuration
Command History
Release
Modification
12.2(17a)SX
Support for this command was introduced on the Supervisor
Engine 720.
12.2(33)SRA
This command was integrated into Cisco IOS Release
12.2(33)SRA.
Usage Guidelines
This command is not supported on Cisco 7600 series routers that are
configured with a Supervisor Engine 2.
All three PDUs (normal BPDU, CDP, and VTP packets) that arrive on
Layer 2-protocol tunnel-enabled ports are rate limited. Rate limiting occurs in
the ingress direction in Layer 2-protocol tunneling. If the rate of the
incoming PDUs exceeds the configured threshold , the excessive PDUs are
dropped.
Examples
This example shows how to enable rate limiting globally:
Router(config)# l2protocol-tunnel global drop-threshold 3000
Router(config)#
Related Commands
Command
Description
l2protocol-tunnel
Enables the protocol tunneling on an interface and
specifies the type of protocol to be tunneled.
l2protocol-tunnelcos
Specifies a CoS value globally on all ingress Layer-2
protocol tunneling ports.
l2protocol-tunneldrop-threshold
Specifies the maximum number of packets that can be
processed for the specified protocol on that interface before being dropped.
l2protocol-tunnelshutdown-threshold
Specifies the maximum number of packets that can be
processed for the specified protocol on that interface in 1 second.
showl2protocol-tunnel
Displays the protocols that are tunneled on an interface or
on all interfaces.
l2protocol-tunnel point-to-point
To enable point-to-point protocol tunneling, use the l2protocol-tunnel point-to-point command in interface configuration mode. To disable, use the no form of this command.
To specify the maximum number of packets that can be processed for
the specified protocol on that interface in 1 second, use the
l2protocol-tunnelshutdown-thresholdcommand in interface configuration mode. To reset all the
threshold values to 0 and disable the shutdown threshold, use the
no form ofthis command.
PortFast BPDU filtering is enabled automatically on tunnel ports.
If you do not specify a protocol, the
packets value applies to all protocols.
You can configure protocol tunneling on switch ports only. You must
enter the
switchport command once without any keywords
to configure the LAN port as a Layer 2 interface before you can enter
additional
switchport commands with keywords. This
action is required only if you have not entered the
switchport command for the interface.
Refer to the “Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol
Tunneling” chapter of the Cisco 7600 Series Router Cisco IOS Software
Configuration Guide for additional information on setting the drop threshold
value.
Examples
This example shows how to specify the maximum number of CDP packets
that can be processed on that interface in 1 second:
Enables the protocol tunneling on an interface and
specifies the type of protocol to be tunneled.
showl2protocol-tunnel
Displays the protocols that are tunneled on an interface or
on all interfaces.
switchport
Modifies the switching characteristics of the Layer
2-switched interface.
l3vpn encapsulation ip
To configure an L3VPN encapsulation profile, use the l3vpnencapsulationip command in global configuration mode. To remove the encapsulation profile, use the no form of this command.
l3vpnencapsulationipprofilename
nol3vpnencapsulationipprofilename
Syntax Description
profilename
Name of the Layer 3 encapsulation profile.
Command Default
The L3VPN encapsulation profile is not configured.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.2(33)SRE
This command was introduced.
Usage Guidelines
When you use the l3vpnencapsulationip command you enter into L3VPN encapsulation configuration mode. You can then specify the transport source mode and interface using thetransportipv4 command, set the GRE key using the protocolgre command, and configure the L3VPN encapsulation profile.
Examples
The following example shows how to configure an L3VPN encapsulation profile:
Router(config)# l3vpn encapsulation ip tunnelencap
Related Commands
Command
Description
showl3vpnencapsulationip
Displays the profile health and the underlying tunnel interface.
transportipv4
Specifies IPv4 transport source mode and the transport source interface.
protocolgre
Specifies GRE as the tunnel mode and sets the GRE key.
lacp active-port distribution automatic
To have an effective auto interleaved port priority distribution of active and bundled ports across different slots that are part of the same port channel distributed EtherChannel (DEC) and multichassis EtherChannel (MEC), use the lacpactive-portdistributionautomaticcommand in port channel configuration mode.
lacpactive-portdistributionautomatic
nolacpactive-portdistributionautomatic
Syntax Description
This command has no keywords or arguments.
Command Default
Auto interleaved port priority is disabled.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
12.2(33)SXI4
This command was introduced.
Usage Guidelines
The auto interleaved port-priority feature automatically distributes active and bundled ports based on the position of a port link when it comes up and is effective only if you configure it on the system that has the higher LACP system priority.
The port priority per port that you configured continues to take precedence over a dynamic port number. You need to perform a shutdown and no shutdown on the interface port channel to enable the auto interleaved port priority feature on all ports.
Examples
This example shows how to configure interleaved port priority:
Router(config)# interface port23
Router(config-if)# lacp active-port distribution automatic
Please shut/no shut the port-channel for configuration to take effect immediately.
Router(config-if)# shutdown
Router(config-if)# no shutdown
Router(config-if)# end
This example shows how to verify that interleaved port priority is configured:
Router# show running interface port23
Building configuration...
Current configuration : 81 bytes
!
interface Port-channel23
no switchport
no ip address
lacp max-bundle 4
lacp active-port distribution automatic
end
Router# show etherchannel 23 summary
Flags: D - down P - bundled in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
U - in use N - not in use, no aggregation
f - failed to allocate aggregator
M - not in use, no aggregation due to minimum links not met
m - not in use, port not aggregated due to minimum links not met
u - unsuitable for bundling
d - default port
w - waiting to be aggregated
Number of channel-groups in use: 9
Number of aggregators: 9
Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
23 Po23(RU) LACP Gi1/1/21(P) Gi1/1/22(P) Gi1/1/23(P)
Gi1/1/24(P) Gi2/1/17(H) Gi2/1/18(H)
Gi2/1/19(H) Gi2/1/20(H)
Last applied Hash Distribution Algorithm: Fixed
Note
The four active and bundled ports are from the same chassis and slot.
Related Commands
Command
Description
showetherchannel
Displays EtherChannel information for a port channel.
lacp fast-switchover
To enable Link Aggregation Control Protocol (LACP) 1:1 link redundancy, use the lacpfast-switchover command in interface configuration mode. To dis
able LACP 1:1 link redundancy,
use the no form of this command.
lacpfast-switchover
nolacpfast-switchover
Syntax Description
This command has no arguments or keywords.
Command Default
LACP 1:1 link redundancy is disabled by default.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
12.2(33)SXH
This command was introduced.
12.2(33)SRC
This command was integrated into Cisco IOS Release 12.2(33)SRC.
12.2(33)SB
Support for this command was implemented on the Cisco 10000 series router and integrated into Cisco IOS Release 12.2(33)SB. The time allowed for a link switchover was modified from the default of 2 seconds to 250 milliseconds.
Cisco IOS XE Release 2.5
This command was integrated into Cisco IOS XE Release 2.5
Usage Guidelines
Prior to entering the lacpfast-switchover command, you must ensure the following:
The port channel protocol type is LACP.
Thelacpmax-bundle1command has been entered on the port channel. Thelacpfast-switchover command will not affect the lacpmax-bundle command.
When you enable LACP 1:1 link redundancy, based on the system priority and port priority, the port with the higher system priority chooses the link as the active link and the other link as the standby link. When the active link fails, the standby link is selected as the new active link without taking down the port channel. When the original active link recovers, it reverts to its active link status. During this change-over, the port channel is also up.
Note
We recommend that you configure two ports only (one active and one hot-standby) in the bundle for optimum performance.
You can enter this command on any port channels with different EtherChannel protocol types of LACP, Port Aggregation Protocol (PAgP), or Fast EtherChannel (FEC).
Examples
This example shows how to enable LACP 1:1 link redundancy:
Router(config-if)# lacp fast-switchover
This example shows how to disable LACP 1:1 link redundancy:
Router(config-if)# no lacp fast-switchover
Related Commands
Command
Description
lacpmax-bundle
Assigns and configures an EtherChannel interface to an EtherChannel group.
showetherchannel
Displays the EtherChannel information for a channel.
lacp max-bundle
To define the maximum number of active bundled Link Aggregation
Control Protocol (LACP) ports allowed in a port channel, use the
lacpmax-bundle command in interface configuration
mode. To return to the default settings, use the
no form of this command.
lacpmax-bundlemax-bundles
nolacpmax-bundle
Syntax Description
max-bundles
Maximum number of active bundled ports allowed in the port
channel. Valid values are from 1 to 8. On the Cisco ASR 1000 series router,
valid values are 1 to 4.
The default settings are as follows:
Maximum of 8
bundled ports per port channel.
Maximum of 8
bundled ports and 8 hot-standby ports per port channel if the port channels on
both sides of the LACP bundle are configured in the same way.
On the Cisco
10000 series router, maximum of 8 bundled ports per port channel.
Command Default
A maximum number of active bundled ports is not configured.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
12.2(18)SXD
Support for this command was introduced on the Supervisor
Engine 720.
12.2(33)SRA
This command was integrated into Cisco IOS Release
12.2(33)SRA.
12.2(31)SB2
Support for this command was implemented on the Cisco 10000
series router and integrated into Cisco IOS Release 12.2(31)SB2.
12.2(33)SRB
Support for this command on the Cisco 7600 router was
integrated into Cisco IOS Release 12.2(33)SRB.
12.2(33)SB
On the Cisco 10000 series router, the maximum number of
bundled ports per port channel was increased from 4 to 8.
Cisco IOS XE Release 2.4
This command was integrated into Cisco IOS XE Release 2.4.
12.2(33)SRE
This command was integrated into Cisco IOS Release
12.2(33)SRE.
Usage Guidelines
The value specified in the
max-bundles argument determines the number of
active links that are bundled in the port channel. The remaining links are in
hot-standby mode.
On the Cisco 10000 series router, this command requires a Performance
Routing Engine 2 (PRE2) or PRE3.
Examples
This example shows how to set 3 ports to bundle in port channel 2:
Creates a port-channel virtual interface and puts the CLI
in interface configuration mode.
ipaddress
Sets a primary or secondary IP address on an interface.
showetherchannel
Displays the EtherChannel information for a channel.
showinterfacesport-channel
Displays traffic that is seen by a specific port channel.
lacp port-priority
To set the priority for a physical interface, use the
lacpport-priority command in interface configuration mode. To return to the default setting, use the
no form of this command.
lacpport-prioritypriority
nolacpport-priority
Syntax Description
priority
Integer from 1 to 65535 that indicates the priority for the physical interface. The default is 32768.
On the Cisco ASR 1000 series router, the range is 0 to 65535.
Command Default
The default port priority is set.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
12.1(13)EW
This command was introduced on the Cisco Catalyst 4500 series switches.
12.2(14)SX
Support for this command on the Supervisor Engine 720 was integrated into Cisco IOS Release12.2(14)SX.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was integrated into Cisco IOS Release12.2(17d) SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(31)SB2
This command was integrated into Cisco IOS Release 12.2(31)SB2.
12.2(33)SRB
Support for this command on the Cisco 7600 router was integrated into Cisco IOS Release 12.2(33)SRB.
Cisco IOS XE Release 2.4
This command was integrated into Cisco IOS XE Release 2.4.
15.1(2)SNG
This command was implemented on the Cisco ASR 901 Series Aggregation Services Router.
Usage Guidelines
You may assign a port priority to each port on a device running Link Aggregation Control Protocol (LACP). You can specify the port priority by using the
lacpport-priority command at the command-line interface (CLI) or use the default port priority (32768) that is carried as part of the LACP protocol data unit (PDU) exchanged with the partner. Port priority is used to decide which ports should be put in standby mode when a hardware limitation or the
lacpmax-bundle command configuration prevents all compatible ports from aggregating. Priority is supported only on port channels with LACP-enabled physical interfaces.
Note
A high priority number means a low priority.
Port priority together with port number form a port identifier.
To verify the configured port priority, issue the
showlacp command.
Examples
This example shows how to set a priority of 23700 for an interface:
Assigns and configures an EtherChannel interface to an EtherChannel group.
debuglacp
Enables debugging of LACP activities.
lacpmax-bundle
Defines the maximum number of active bundled LACP ports allowed in a port channel.
lacpsystem-priority
Sets the priority of the system.
showlacp
Displays information about LACP activity on the device.
lacp rate
To set the rate at which Link Aggregation Control Protocol (LACP) control packets are ingressed to an LACP-supported interface, use thelacprate command in interface configuration mode. To return to the default settings, use the no form of this command.
lacprate
{ normal | fast }
nolacprate
Syntax Description
normal
Specifies that LACP control packets are ingressed at the normal rate, every 30 seconds after the link is bundled.
fast
Specifies that LACP control packets are ingressed at the fast rate, once every 1 second.
Command Default
The default ingressed rate for control packets is 30 seconds after the link is bundled.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
12.2(18)SXF2
This command was introduced on the Catalyst 6500 series switch.
12.2(33)SRC
This command was integrated into Cisco IOS Release 12.2(33)SRC.
Cisco IOS XE Release 3.6S
This command was implemented on Cisco ASR 1000 Series Aggregation Services Routers in Cisco IOS XE Release 3.6S.
Usage Guidelines
Use this command to modify the duration of a LACP timeout. The LACP timeout value is set on Cisco switches to a value of 90 seconds. Using the lacprate command, you can select the LACP timeout value for a switch to be either 30 seconds or 1 second.
This command is supported only on LACP-enabled interfaces.
Examples
This example shows how to specify the fast (1-second) ingress rate on interface Ethernet 0/1:
Router(config)# interface ethernet 0/1
Router(config-if)# lacp rate fast
Related Commands
Command
Description
showlacp
Displays LACP information.
lacp system-priority
To set the priority for a system, use the
lacpsystem-priority command in global configuration mode. To return to the default setting, use the
no form of this command.
lacpsystem-prioritypriority
nolacpsystem-priority
Syntax Description
priority
Integer from 1 to 65535 that indicates the priority for the system. The default is 32768.
On the Cisco ASR 1000 series router, the range is 0 to 65535.
Command Default
The default system priority is set.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.1(13)EW
This command was introduced on the Cisco Catalyst 4500 series switches.
12.2(14)SX
Support for this command on the Supervisor Engine 720 was integrated into Cisco IOS Release12.2(14)SX.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was integrated into Cisco IOS Release12.2(17d) SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(31)SB2
This command was integrated into Cisco IOS Release 12.2(31)SB2.
12.2(33)SRB
Support for this command on the Cisco 7600 router was integrated into Cisco IOS Release 12.2(33)SRB.
Cisco IOS XE Release 2.4
This command was integrated into Cisco IOS XE Release 2.4.
15.1(2)SNG
This command was implemented on the Cisco ASR 901 Series Aggregation Services Router.
Usage Guidelines
You can assign a system priority to each device running Link Aggregation Control Protocol (LACP). You can specify the system priority by using the
lacpsystem-priority command at the command-line interface (CLI) or use the default system priority (32768) that is carried as part of the LACP protocol data unit (PDU) exchanged with the partner. System priority is used with the MAC address of the device to form the system ID and also is used during negotiation with other systems. Priority is supported only on port channels with LACP-enabled physical interfaces.
Note
A high priority number means a low priority.
To verify the configured system priority, issue the
showlacp command.
Examples
The following example shows how to set a system priority of 25500 for a device:
Assigns and configures an EtherChannel interface to an EtherChannel group.
debuglacp
Enables debugging of LACP activities.
lacpport-priority
Sets the priority of a port.
showlacp
Displays information about LACP activity on the device.
lbo
To set a cable length longer than 655 feet for a DS-1 link, use thelbocommand in interface configuration mode on the interface for a T1 link. To delete the
lbovalue, use the
no form of this command.
Specifies the long-haul mode where the gain and line build out must be configured.
gain26
Specifies the decibel pulse gain at 26 decibels. This is the default pulse gain.
gain36
Specifies the decibel pulse gain at 36 decibels.
-15db
Specifies the decibel pulse rate at -15 decibels.
-22.5db
Specifies the decibel pulse rate at -22.5 decibels.
-7.5db
Specifies the decibel pulse rate at -7.5 decibels.
0db
Specifies the decibel pulse rate at 0 decibels. This is the default.
short
Specifies the short-haul mode where the cable length, in feet, must be configured.
133
Specifies a cable length from 0 to 133 feet.
266
Specifies a cable length from 134 to 266 feet.
399
Specifies a cable length from 267 to 399 feet.
533
Specifies a cable length from 400 to 533 feet.
655
Specifies a cable length from 534 to 655 feet.
Command Default
gain26 and0db
Command Modes
Interface configuration
Command History
Release
Modification
11.3MA
This command was introduced as a Cisco MC3810 controller configuration command.
12.0(5)XE
The command was introduced as an ATM interface command.
12.0(7)XE1
This command was implemented on Cisco 7100 series routers.
12.1(5)T
This command was integrated into Cisco IOS Release 12.1(5)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command is supported on T1 links only.
Each T1 port can operate in long-haul or short-haul mode. In long haul mode, the user must specify the gain and the line build out. In short-haul mode, the user must specify the cable length in feet.
The transmit attenuation value is best obtained by experimentation. If the signal received by the far-end equipment is too strong, reduce the transmit level by entering additional attenuation.
Examples
On Cisco 7100 or Cisco 7200 series routers, the following example specifies a pulse gain of 36 decibels and a decibel pulse rate of -7.5 decibels:
Router(config)# interface atm 1/2
Router(config-if)# lbo long gain36 -7.5db
lex burned-in-address
To set the
burned-in MAC address for a LAN Extender interface, use the lexburned-in-address command in interface configuration mode. To clear the burned-in MAC address, use the no form of this command.
lexburned-in-addressieee-address
nolexburned-in-addresslexburned-in-addresscommand
Syntax Description
ieee-address
48-bit IEEE MAC address written as a dotted triplet of 4-digit hexadecimal numbers.
Command Default
No burned-in MAC address is set.
Command Modes
Interface configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(15)T
This command is no longer supported in Cisco_IOS Mainline or Technology-based (T) releases. It may continue to appear in Cisco_IOS 12.2S-family releases.
Usage Guidelines
Use this command only on a LAN Extender interface that is not currently active (not bound to a serial interface).
Examples
The following example sets the burned-in MAC address on LAN Extender interface 0:
Router(config)# interface serial 4
Router(config-if)# encapsulation ppp
Router(config)# interface lex 0
Router(config-if)# lex burned-in-address 0000.0c00.0001
Router(config-if) ip address 10.108.172.21 255.255.255.0
lex input-address-list
To assign an
access list that filters on MAC addresses, use the lexinput-address-list command in interface configuration mode. To remove an access list from the interface, use the no form of this command.
Number of the access list assigned with the access-list global configuration command. It can be a number from 700 to 799.
Command Default
No access lists are preassigned to a LAN Extender interface.
Command Modes
Interface configuration
Command History
Release
Modification
10.0
This command was introduced.
12.2(15)T
This command is no longer supported in Cisco_IOS Mainline or Technology-based (T) releases. It may continue to appear in Cisco_IOS 12.2S-family releases.
Usage Guidelines
Use the lexinput-address-list command to filter the packets that are allowed to pass from the LAN Extender to the core router. The access list filters packets on the basis of the source MAC address.
The LAN Extender interface does not process MAC-address masks. Therefore, you should omit the mask from the access-list commands.
For LAN Extender interfaces, an implicit permit everything entry is automatically defined at the end of an access list. Note that this default differs from other access lists, which have an implicit deny everything entry at the end of each access list.
Examples
The following example applies access list 710 to LAN Extender interface 0. This access list denies all packets from MAC address 0800.0214.2776 and permits all other packets.
Configures the access list mechanism for filtering frames by protocol type or vendor code.
lex input-type-list
To assign an
access list that filters Ethernet packets by type code, use the lexinput-type-list command in interface configuration mode. To remove an access list from an interface, use the no form of this command.
lexinput-type-listaccess-list-number
nolexinput-type-listlexinput-type-listcommand
Syntax Description
access-list-number
Number of the access list that you assigned with the access-list command. It can be a number in the range 200 to 299.
Command Default
No access lists are preassigned to a LAN Extender interface.
Command Modes
Interface configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(15)T
This command is no longer supported in Cisco_IOS Mainline or Technology-based (T) releases. It may continue to appear in Cisco_IOS 12.2S-family releases.
Usage Guidelines
Filtering is done on the LAN Extender chassis.
The LAN Extender interface does not process masks. Therefore, you should omit the mask from the access-list commands.
For LAN Extender interfaces, an implicit permit everything entry is automatically defined at the end of an access list. Note that this default differs from other access lists, which have an implicit deny everything entry at the end of each access list.
Examples
The following example applies access list 220 to LAN Extender interface 0. This access list denies all AppleTalk packets (packets with a type field of 0x809B) and permits all other packets.
Configures the access list mechanism for filtering frames by protocol type or vendor code.
lex priority-group
To activate
priority output queueing on the LAN Extender, use the lexpriority-group command in interface configuration mode. To disable priority output queueing, use the no form of this command.
lexpriority-groupgroup
nolexpriority-group
Syntax Description
group
Number of the priority group. It can be a number in the range 1 to 10.
Command Default
Disabled
Command Modes
Interface configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(15)T
This command is no longer supported in Cisco_IOS Mainline or Technology-based (T) releases. It may continue to appear in Cisco_IOS 12.2S-family releases.
Usage Guidelines
To define queueing priorities, use the priority-listprotocol global configuration command. Note that you can use only the following forms of this command:
priority-list
list
protocol
protocol
{
high
|
medium
|
normal
|
lowpriority-list
list
protocolbridge
{
high
|
medium
|
normal
|
low
}
list
list-number
If you specify a protocol that does not have an assigned Ethernet type code, such as x25, stun, or pad, it is ignored and will not participate in priority output queueing.
Examples
The following example activates priority output queueing on LAN Extender interface 0:
Router(config-if)# priority-list 5 protocol bridge medium list 701
Router(config-if)# lex interface 0
Router(config-if)# lex priority-group 5
Related Commands
Command
Description
priority-listprotocol
Establishes queueing priorities based on the protocol type.
lex retry-count
To define the number of times to
resend commands to the LAN Extender chassis, use the lexretry-count command in interface configuration mode. To return to the default value, use the no form of this command.
lexretry-countnumber
nolexretry-countnumberlexretry-countcommand
Syntax Description
number
Number of times to retry sending commands to the LAN Extender. It can be a number in the range 0 to 100. The default is 10.
Command Default
10 retries
Command Modes
Interface configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(15)T
This command is no longer supported in Cisco_IOS Mainline or Technology-based (T) releases. It may continue to appear in Cisco_IOS 12.2S-family releases.
Usage Guidelines
After the router has sent a command the specified number of times without receiving an acknowledgment from the LAN Extender, it stops sending the command altogether.
Examples
The following example resends commands 20 times to the LAN Extender:
Defines the amount of time to wait for a response from the LAN Extender.
lex timeout
To define the amount of time to wait for a response from the
LAN Extender, use the lextimeout command in interface configuration mode. To return to the default time, use the no form of this command.
lextimeoutmilliseconds
nolextimeout [milliseconds] lextimeoutcommand
Syntax Description
milliseconds
Time, in milliseconds, to wait for a response from the LAN Extender before resending the command. It can be a number in the range 500 to 60,000. The default is 2000 ms.
Command Default
2000 ms (2 seconds)
Command Modes
Interface configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(15)T
This command is no longer supported in Cisco_IOS Mainline or Technology-based (T) releases. It may continue to appear in Cisco_IOS 12.2S-family releases.
Usage Guidelines
The lextimeout command defines the amount of time that the router waits to receive an acknowledgment after having sent a command to the LAN Extender.
Examples
The following example causes unacknowledged packets to be resent at 4-second intervals:
Defines the number of times to resend commands to the LAN Extender chassis.
linecard-group y-cable
To create a line card group for one-to-one line card redundancy, use the linecard-group y-cable command in redundancy mode. To remove the line card redundancy group, use the no form of this command.
linecard-grouplinecard-groupIdy-cable
nolinecard-grouplinecard-groupIdy-cable
Syntax Description
linecard-groupId
An unsigned integer in the range 0 to the (maximum number of chassis line card subslots/2) -1.
y-cable
The link protection type for the line card group.
Command Default
Nodefaultbehaviororvalues.
Command Modes
Redundancy
Command History
Release
Modification
12.2(28)SB
This command was introduced on the Cisco 10000 series router.
Usage Guidelines
The no linecard-group y-cable command removes the line card redundancy group and frees the linecard-groupIdfor reuse. The no linecard-group y-cable command succeeds only if there are no subslot members in the line card redundancy group.
Examples
The following example creates
line card group number 1 for one-to-one line card redundancy:
Configures the redundancy role of a line card in the line card group.
redundancy
Enters redundancy mode.
showredundancylinecard
Displays information about a redundant line card or line card group.
linecode
To select the
line-code type for T1 or E1 lines, use the linecode command in controller configuration mode.
linecode
{ ami | b8zs | hdb3 }
Syntax Description
ami
Specifies alternate mark inversion (AMI) as the line-code type. Valid for T1 or E1 controllers. This is the default for T1 lines.
b8zs
Specifies B8ZS as the line-code type. Valid for T1 controller only.
hdb3
Specifies high-density bipolar 3 (hdb3) as the line-code type. Valid for E1 controller only. This is the default for E1 lines.
Command Default
AMI is the default for T1 lines.
High-density bipolar 3
is the default for E1 lines.
Command Modes
Controller configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Use this command in configurations in which the router or access server must communicate with T1 fractional data lines. The T1 service provider determines which line-code type, either ami or b8zs, is required for your T1 circuit. Likewise, the E1 service provider determines which line-code type, either ami or hdb3, is required for your E1 circuit.
This command does not have a no form.
Examples
The following example specifies B8ZS as the line-code type:
Router(config-controller)# linecode b8zs
line-mode
To configure the mode of the controller for the Symmetrical High-Speed Digital Subscriber Line (SHDSL) port, use the
line-mode command in controller configuration mode. To return to the default two-wire mode, use the
no form of this command.
line-mode
[ 2-wire | 4-wire
[ enhanced | standard ] | auto ]
noline-mode
Syntax Description
2-wire
(Optional) Configures the controller to operate in two-wire mode.
4-wire
(Optional) Configures the controller to operate in four-wire mode.
enhanced
(Optional) Configures 4-wire mode to exchange handshake status on both wire pairs. This is the default if the handshake mode is not specified.
standard
(Optional) Configures 4-wire mode to exchange handshake status on the master wire pair only.
auto
(Optional) Configures the controller to automatically operate in the mode to match the other line termination. This mode is compatible with a remote host that is in one of the following modes:
line-mode 2-wire line 0
line-mode 2-wire line 1
line-mode 4-wire enhanced
Command Default
The default is two-wire mode if this command is omitted or if the
4-wire keyword is omitted.
Command Modes
Controller configuration
Command History
Release
Modification
12.3(4)XD
This command was introduced on Cisco 2600 series and Cisco 3700 series routers.
12.3(7)T
This command was integrated into Cisco IOS Release 12.3(7)T on Cisco 2600 series and Cisco 3700 series routers.
12.3(11)T
This command was implemented on Cisco 2800 and Cisco 3800 series routers.
12.3(14)T
This command was implemented on Cisco 1800 series routers.
12.4(2)XA
The
enhanced and
standard keywords were added to four-wire mode.
12.4(5)A
Modified
auto keyword to to disallow use of
line-rate command
12.4(4)T
Modified
auto keyword to to disallow use of
line-rate command
Usage Guidelines
This command is used to configure the controller for two-wire or four-wire mode.
Note
To operate in four-wire mode for SHDSL, the
line-mode4-wirecommand must be set.
Note
When the
line-mode command is set to
auto, the
line-rate command is not available.
Examples
Examples
The following example shows how to configure the controller mode of DSL on the controller in slot 4 and port 0 to operate in four-wire mode:
The following example configures the controller in slot 1 and port 0. The router is set to terminate as CPE with the line mode automatically selecting between two-wire mode and four-wire mode.
Router(config)# controller dsl 1/0
Router(config-controller)# line-mode auto
Router(config-controller)# line-term cpe
Related Commands
Command
Description
line-rate
Specifies a line rate for the DSL controller.
line-term
Specifies a termination for a line.
line-rate
To specify a line rate for the DSL controller, use the line-rate command in controller configuration mode.
line-rate
{ auto | rate }
Syntax Description
auto
Allows the controller to select the rate. This option is available only in two-wire mode.
rate
DSL line rate, in kbps. The line will train at the selected rate plus 8 kbps of DSL framing overhead. The supported line rates are as follows:
This command was introduced on Cisco 2600 series and Cisco 3700 series routers.
12.3(4)XG
This command was implemented on Cisco 1700 series routers.
12.3(7)T
This command was integrated into Cisco IOS Release 12.3(7)T on Cisco 2600 series and Cisco 3700 series routers.
12.(11)T
This command was implemented on Cisco 2800 and Cisco 3800 series routers.
12.3(14)T
This command was implemented on Cisco 1800 series routers.
12.4(5)A
Modified line-rate command to be disallowed when line-modecommand is set to auto.
12.4(4)T
Modified line-rate command to be disallowed when line-modecommand is set to auto.
Usage Guidelines
This command does not have a no form.
This command specifies the DSL line rate for the Symmetrical High-Speed Digital Subscriber Line (SHDSL) port. Use this command to configure the line rate in two-wire or four-wire mode. The SHDSL rate is in kbps, but the line trains at the selected rate plus two times the 8 kbps of DSL framing overhead.
Note
Automatic rate mode (auto) is used only in two-wire mode. It is not available in four-wire mode.
Note
If different DSL line rates are configured at opposite ends of the DSL uplink, the actual DSL line
rate is always the lower rate.
Note
The maximum peak cell rate is 8 kbps less than the line rate.
Note
When the line-mode command is set to auto, the line-rate command is not available.
Examples
The following example displays the line-mode command selecting four-wire mode, which is different from the previous line mode of the router as indicated by the router output, and then the line rate is selected. The rate of 4608 is selected, and the output of the router is shown.
Router(config)# controller dsl 1/0
Router(config-controller)# line-mode4-wire
Router(config-controller)#
*Jun 15 18:00:48.159: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn
*Jun 15 18:00:50.159: %LINK-3-UPDOWN: Interface ATM1/0, changed state to down
*Jun 15 18:00:51.159: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM1/0, cn
Router(config-controller)# line-rate4608
Router(config-controller)#
*Jun 15 18:01:36.627: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn
*Jun 15 18:01:36.967: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn
Router(config-controller)# exit
Related Commands
Command
Description
line-mode
Configures the mode of the controller.
line-term
Specifies a termination for a line.
line-term
To specify a termination for a line, use the line-term command in controller configuration mode.
line-term
{ co | cpe }
Syntax Description
co
Central office.
cpe
Customer premises equipment. This is the default.
Command Default
The default value is cpe.
Command Modes
Controller configuration
Command History
Release
Modification
12.3(4)XD
This command was introduced on Cisco 2600 series and Cisco 3700 series routers.
12.3(7)T
This command was integrated into Cisco IOS Release 12.3(7)T on Cisco 2600 series and Cisco 3700 series routers.
12.3(11)T
This command was implemented on Cisco 2800 and Cisco 3800 series routers.
12.3(14)T
This command was implemented on Cisco 1800 series routers.
Usage Guidelines
This command does not have a no form.
This command is used to configure the line termination for use as either the central office (CO) or the customer premises equipment (CPE).
Examples
The following example shows how to configure the controller in slot 1 and port 0. The router is set to terminate as CPE with the line mode automatically selecting between two-wire mode and four-wire mode.
Router(config)# controller dsl 1/0
Router(config-controller)# line-termcpe
Router(config-controller)# line-mode auto
No change in line mode
Related Commands
Command
Description
line-mode
Configures the mode of the controller.
line-rate
Specifies a line rate for the DSL controller.
line-termination
To set the line termination on an E1 controller, use the
line-terminationcommand in controller configuration mode. To return to the default line termination, use the
no form of this command.
line-termination
{ 75-ohm | 120-ohm }
noline-termination
Syntax Description
75-ohm
Specifies 75-ohm unbalanced termination.
120-ohm
Specifies 120-ohm balanced termination. This is the default.
Command Default
120-ohms
Command Modes
Controller configuration
Command History
Release
Modification
11.3(2)AA
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command applies only to E1 controllers. To determine the line termination setting for the controller, use the
showcontrollerse1command.
Examples
In the following example, the line termination is set to 75 ohms for the E1 port located in shelf 6, slot 0, port 0:
Displays information about the E1 links supported by the NPM (Cisco 4000) or MIP (Cisco 7500 series).
link debounce
To enable the debounce timer on an interface, use the
linkdebounce command in interface configuration mode. To disable the timer, use the
no form of this command.
linkdebounce
[ timetime ]
nolinkdebounce
Syntax Description
timetime
(Optional) Specifies the extended debounce timer; va lid values are from 100 to 5000 milliseconds.
Command Default
The table below lists the debounce timer defaults.
Table 1 Port Debounce Timer Delay Time
Port Type
Debounce Timer Disabled
Debounce Timer Enabled
10BASE-FL ports
300 milliseconds
3100 milliseconds
10/100BASE-TX ports
300 milliseconds
3100 milliseconds
100BASE-FX ports
300 milliseconds
3100 milliseconds
10/100/1000BASE-TX ports
300 milliseconds
3100 milliseconds
1000BASE-TX ports
300 milliseconds
3100 milliseconds
Fiber Gigabit ports
10 milliseconds
100 milliseconds
10-Gigabit ports except WS-X6501-10GEX4 and WS-X6502-10GE
10 milliseconds
100 milliseconds
WS-X6501-10GEX4 and WS-X6502-10GE 10-Gigabit ports
1000 milliseconds
3100 milliseconds
Command Modes
Interface configuration
Command History
Release
Modification
12.2(14)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(17a)SX
This command was changed to remove support for the following modules:
WS-X6501-10GEX4
WS-X6502-10GE
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
The
timetime keyword and argument are supported on Gigabit Ethernet and 10-Gigabit Ethernet interfaces only.
The
linkdebounce command is not supported on the following modules in releases prior to Release 2.2(17a)SX:
WS-X6501-10GEX4
WS-X6502-10GE
The debounce timer sets the amount of time that the firmware waits before it notifies the software that the link is down. The debounce timer does not apply to linkup because the linkup is immediately notified by the firmware.
The default debounce time applies when you enter the
linkdebounce command with no arguments. For example, when you enter the
linkdebouncetime100 command, it is equivalent to entering the
linkdebounce command with no arguments and you will see the following link debounce entry in the configuration:
interface GigabitEthernet1/1
no ip address
link debounce
Enter the
showinterfacesdebounce command to display the debounce configuration of an interface.
Examples
This example shows how to configure the debounce timer on a Gigabit Ethernet fiber interface:
Router(config-if)# link debounce time 100
Router(config-if)#
Related Commands
Command
Description
showinterfacesdebounce
Displays the status and configuration for the debounce timer.
link state group
To configure the link state group, use the linkstategroup command in interface configuration mode.
linkstategroup [number]
{ upstream | downstream }
Syntax Description
number
Specifies a link-state group. The acceptable range of group number is between 1 to 10 and the default value is 1.
upstream
Configures the interface as an upstream interface in the group.
downstream
Configures the interface as a downstream interface in the group.
Command Default
The default linkstategroupnumber is 1.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
15.1(1)S
This command was introduced.
Usage Guidelines
Link State Ttracking (LST), also known as trunk failover, is a feature that binds the link state of multiple interfaces. When you configure LST for the first time, add upstream interfaces to the link state group before adding the downstream interface, otherwise the downstream interfaces would move into error-disable mode. The maximum number of link state groups configurable is 10. These are the limitations:
An interface can only be an upstream or downstream interface.
An interface cannot be part of more than one link state tracking group.
Examples
The following example shows how to configure the link state group number.
Router# configure terminal
Router(config)# link state track 1
Router(config)# interface gigabitethernet3/1
Router(config-if)# link state group 1 upstream
Router(config-if)# interface gigabitethernet3/3
Router(config-if)# link state group 1 upstream
Router(config-if)# interface gigabitethernet3/5
Router(config-if)# link state group 1 downstream
Router(config-if)# interface gigabitethernet3/7
Router(config-if)# link state group 1 downstream
Related Commands
Command
Description
linkstatetrack
Configures the link-state track number.
showlinkstategroup
Displays the link-state group information.
link state track
To configure a link state tracking number, use the linkstatetrack command in global configuration mode. To restore the default linkstatetracknumber, use the no form of this command.
linkstatetracknumber
nolinkstatetracknumber
Syntax Description
number
Specifies the link state tracking number. The acceptable range is between 1 and 10 and the default value is 1.
Command Default
The default link state track number is 1.
Command Modes
Global configuration (config)
Command History
Release
Modification
15.1(1)S
This command was introduced.
Usage Guidelines
Link State Ttracking (LST), also known as trunk failover, is a feature that binds the link state of multiple interfaces. When you configure LST for the first time, add upstream interfaces to the link state group before adding the downstream interface, otherwise the downstream interfaces would move into error-disable mode.
Examples
The following example shows how to configure the link state tracking number.
Router# configure terminal
Router(config)# link state track 1
Related Commands
Command
Description
linkstategroup
Configures the link state group and the interface as either an upstream or downstream interface in the group.
showlinkstategroup
Displays the link state group information.
li-slot rp rate
To apply the user specified Packets Per Second (PPS) value when an Lawful Intercept (LI) is provisioned in RP mode, use the
li-slotrprate command in global configuration mode. To disable the user specified value, use the no form of this command .
li-slotrpratepps
Syntax Description
pps
Packets per second (pps). The range is from 10 to 8500 for SUP720, 10 to 6000 for SUP32, and 10 to 12000 for RSP720.
Command Default
No default behavior or values.
Command Modes
Global configuration (config)
Command History
Release
Modification
15.0(1)S5
This command was introduced on the Cisco 7600 series routers.
Examples
This example shows how to apply PPS value when an LI is provisioned in RP mode:
router# configure terminal
router(config)# li-slot rp rate 5000
Related Commands
Command
Description
showmlsrate-limit
Displays information about the configured rate limiters.
link-test
To reenable the
link-test function on a port on an Ethernet hub of a Cisco 2505 or Cisco 2507 router, use the link-test command in hub configuration mode. To disable this function, use the no form of this command.
link-testcommandlink-test
nolink-test
Syntax Description
This command has no arguments or keywords.
Command Default
Enabled
Command Modes
Hub configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command applies to a port on an Ethernet hub only. Disable this feature if a 10Base-T twisted-pair device at the other end of the hub does not implement the link test function.
Examples
The following example disables the link test function on hub 0, ports 1 through 3:
Router(config)#
hub ethernet 0 1 3
Router(config-hub)#
no link-test
Related Commands
Command
Description
hub
Enables and configures a port on an Ethernet hub of a Cisco 2505 or Cisco 2507 router.
load-balancing
To apply a load-balancing method to a Gigabit EtherChannel (GEC) interface, use the load-balancing command in interface configuration mode. To reset to the default, use the no form of this command.
load-balancing
{ flow | vlan }
noload-balancing
Syntax Description
flow
Flow-based load balancing is used.
vlan
VLAN-manual load balancing is used.
Command Default
The port channel uses the global load-balancing configuration.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
Cisco IOS XE Release 2.5
This command was introduced.
Usage Guidelines
The load-balancing command sets the load-balancing method on a specific port channel. The load-balancing method configured with this command takes precedence over the global configuration defined with the port-channelload-balancingvlan-manual command.
If you do not explicitly configure load balancing either globally or on the port channel, the load-balancing method on the port channel is set to flow-based.
Load balancing uses the concept of buckets to map traffic flows to the member links of the port channel. The different traffic flows are mapped to the buckets and each bucket has one active member link associated with it. All flows that are mapped to a bucket use the member link associated with that bucket.
There are two methods of load balancing on a GEC interface:
VLAN-manual--All packets forwarded over the same VLAN subinterface are considered part of the same flow and are mapped to the member link specified in the configuration.
Flow-based--Traffic flows are mapped to different member links based on the packet header.
Examples
This example shows how to set the load-balancing method to VLAN-manual:
Applies the VLAN-manual load-balancing method globally to all GEC interfaces.
showinterfacesport-channeletherchannel
Displays the load-balancing bucket distribution currently in use for a GEC interface.
showetherchannelload-balancing
Displays the load-balancing method applied to GEC interfaces.
load-interval
To change the length of time for which data is used to compute load statistics, use theload-interval command in interface configuration mode or Frame Relay DLCI configuration mode. To revert to the default setting, use the
noform of this command.
load-intervalseconds
noload-intervalseconds
Syntax Description
seconds
Length of time for which data is used to compute load statistics. Value is a multiple of 30, from 30 to 600 (30, 60, 90, 120, and so on). The default is 300 seconds.
This command was made available in Frame Relay DLCI configuration mode.
12.2(18)SXF
Support for this command was introduced on the Supervisor Engine 720.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
15.1(2)SNG
This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.
Usage Guidelines
To make computations more reactive to short bursts of traffic, you can shorten the length of time over which load averages are computed.
If the load interval is set to 30 seconds, new data is used for load calculations over a 30-second period. This data is used to compute load statistics, including the input rate in bits and packets per second, the output rate in bits and packets per second, the load, and reliability.
Load data is gathered every five seconds. This data is used for a weighted-average calculation in which recent load data has more weight in the computation than older load data. If the load interval is set to 30 seconds, the average is computed for the last 30 seconds of load data.
If you change the calculation interval from the default of five minutes to a shorter period of time, the input and output statistics that are displayed by theshowinterface command or the
showframe-relaypvc command will be more current and will be based on more nearly instantaneous data, rather than reflecting the average load over a longer period of time.
This command is often used for dial backup purposes to increase or decrease the likelihood of implementation of a backup interface, but it can be used on any interface.
Examples
Examples
In the following example, the default average of five minutes is changed to a 30-second average. A burst in traffic that would not trigger a dial backup for an interface configured with the default five-minute interval might trigger a dial backup for this interface, which is set for the shorter 30-second interval.
Router(config)# interface serial 0
Router(config-if)# load-interval 30
Examples
In the following example, the load interval is set to 60 seconds for a Frame Relay PVC with the DLCI 100:
Displays statistics for all interfaces configured on the router or access server.
local ip address
To define an IP address to identify a local circuit emulation (CEM) channel, use the localipaddresscommand in CEM xconnect configuration mode.
localipaddressip-address
Syntax Description
ip-address
IP address of a regular or loopback interface in the local router. Default is 0.0.0.0
Command Default
The default local IP address is 0.0.0.0 for a CEM channel.
Command Modes
CEM xconnect configuration
Command History
Release
Modification
12.3(7)T
This command was introduced.
Usage Guidelines
This command does not have a no form. To remove a local IP address, either configure a new local IP address or enter the noxconnect command to disable the connection and all its parameters.
The local IP address used to identify the local end of a CEM connection must be the same as the IP address defined by the remote-ip-addressargument used in the xconnect command to identify the CEM channel at the other end of the CEM connection.
Note
If there are multiple CEM connections that originate from the same router, they may share the same
local IP address provided that each local IP address defines a unique UDP port number using thelocaludpport command.
Examples
The following example demonstrates how to configure the IP address of the local endpoint of the CEM over IP (CEoIP) connection.
Router(config-cem-xconnect)# local ip address 10.0.5.1
Related Commands
Command
Description
clearcem
Clears CEM statistics.
localudpport
Defines the UDP port at the local end of a CEM connection.
showcem
Displays CEM statistics.
xconnect(CEM)
Builds one end of a CEM connection and enters CEM xconnect configuration mode.
local udp port
To define the User Datagram Protocol (UDP) port of the local endpoint of a circuit emulation (CEM) connection, use the localudpportcommand in CEM xconnect configuration mode.
localudpportport
Syntax Description
port
Number of the CEM local UDP port. Possible values are 0, 2141, and 15872 through 16383. The default is 0.
Command Default
The default local UDP port number is 0 for the local endpoint of a CEM connection.
Command Modes
CEM xconnect configuration
Command History
Release
Modification
12.3(7)T
This command was introduced.
Usage Guidelines
This command does not have a no form. To remove a local UPD port number, either configure a new UPD port number or enter the noxconnect command to disable the connection and all its parameters.
Examples
The following example demonstrates how to configure the UDP port of the local endpoint of the CEM over IP (CEoIP) connection.
Router(config-cem-xconnect)# local udp port 2141
Related Commands
Command
Description
remoteudpport
Defines the UDP port of the remote endpoint of a CEM connection.
showcem
Displays CEM channel statistics.
xconnect(CEM)
Builds one end of a CEM connection and enters CEM xconnect configuration mode.
local-lnm
To enable
Lanoptics Hub Networking
Management of a PCbus Token Ring interface, use the local-lnm command in interface configuration mode. To disable Lanoptics Hub Networking Management, use the no form of this command.
local-lnmcommandlocal-lnm
nolocal-lnm
Syntax Description
This command has no arguments or keywords.
Command Default
Management is not enabled.
Command Modes
Interface configuration
Command History
Release
Modification
10.3
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
The Token Ring interface on the AccessPro PC card can be managed by a remote LAN manager over the PCbus interface. At present, the Lanoptics Hub Networking Management software running on an IBM compatible PC is supported.
Examples
The following example enables Lanoptics Hub Networking Management:
Router(config-if)# local-lnm
logging event
To enable notification of interface, subinterface, and Frame Relay data link connection identifier (DLCI) data link status changes, use the
loggingevent command in interface configuration mode. To disable notification, use the
no form of this command.
Enables notification of Frame Relay DLCI status changes.
Note
This option is supported only when the encapsulation on the interface is Frame Relay.
link-status
Enables notification of interface data link status changes.
subif-link-status
Enables notification of subinterface data link status changes.
ignore-bulk
Suppresses link status messages for subinterfaces when they are caused by a state change of the main interface.
Command Default
For system images, notification of interface, subinterface, and Frame Relay DLCI data link status changes is enabled by default.
For boot images, notification of Frame Relay subinterface and DLCI data link status changes is disabled by default. Notification of interface data link status changes is enabled by default.
Command Modes
Interface configuration
Command History
Release
Modification
12.0
This command was introduced.
12.2(32)S
The
ignore-bulk keyword was integrated into the Cisco IOS Release 12.2(32)S.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.3(7)T
The
ignore-bulk keyword was integrated into Cisco IOS Release 12.3(7)T.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Examples
The following example shows how to enable notification of subinterface link status changes:
The following are examples of Frame Relay DLCI and subinterface status change notification messages filtered by the
loggingevent command:
00:16:22: %FR-5-DLCICHANGE: Inteface Serial3/0/0:1 - DLCI 105 state changed to INACTIVE
00:16:22: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial3/0/0:1.5, changed state to down
logging source-interface
To specify the source IPv4 or IPv6 address of system logging packets, use the loggingsource-interface
command in global configuration mode
. To remove the source designation, use the no form of this command.
loggingsource-interfacetypenumber
nologgingsource-interface
Syntax Description
typenumber
Interface type and number.
Command Default
The wildcard interface address is used.
Command Modes
Global configuration (config)
Command History
Release
Modification
11.2
This command was introduced.
12.4(4)T
This command was modified. IPv6 support was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command can be configured on the Virtual Routing and Forwarding (VRF) and non-VRF interfaces. Normally, a syslog message contains the IPv4 or IPv6 address of the interface used to leave the router. The loggingsource-interface command configures the syslog packets contain the IP or IPv6 address of a particular interface, regardless of which interface the packet uses to exit the router.
When no specific interface is configured, a wildcard interface address of 0.0.0.0 (for IPv4) or :: (for IPv6) is used, and the IP socket selects the best outbound interface.
Examples
In the following example, the user specifies that the IP address of Ethernet interface 0 is the source IP address for all syslog messages:
The following sample output displays that the loggingsource-interface command is configured on a VRF source interface:
Router# show running interface loopback49
Building configuration...
Current configuration : 84 bytes
!
interface Loopback49
ip vrf forwarding black
ip address 49.0.0.1 255.0.0.0
end
Router# show running | includes logging
logging source-interface Loopback49 vrf black
logging host 130.0.0.1 vrf black
Related Commands
Command
Description
logging
Logs messages to a syslog server host.
logging event link-status (global configuration)
To change the default or set the link-status event messaging during system initialization, use the
loggingeventlink-status command in global configuration mode. To disable the link-status event messaging, use the
no form of this command.
loggingeventlink-status
{ default | boot }
nologgingeventlink-status
{ default | boot }
Syntax Description
default
Enables system logging of interface state-change events on all interfaces in the system.
boot
Enables system logging of interface state-change events on all interfaces in the system during system initialization.
Command Default
Interface state-change messages are not sent.
Command Modes
Global configuration
Command History
Release
Modification
12.2(14)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
You do not have to enter the
loggingeventlink-statusboot command to enable link-status messaging during system initialization. The
loggingeventlink-statusdefault command logs system messages even during system initialization.
If you enter both the
loggingeventlink-statusdefault and the
nologgingeventlink-statusbootcommands, the interface state-change events are logged after all modules in the Cisco 7600 series router come online after system initialization. The
loggingeventlink-statusdefault and the
nologgingeventlink-statusboot commands are saved and retained in the running configuration of the system.
When both the
loggingeventlink-statusdefault and the
nologgingeventlink-statusbootcommands are present in the running configuration and you want to display the interface state-change messages during system initialization, enter the
loggingeventlink-statusboot command.
Examples
This example shows how to enable the system logging of the interface state-change events on all interfaces in the system:
To enable link-status event messaging on an interface, use the
loggingeventlink-status command in interface configuration mode. To disable link-status event messaging, use the
no form of this command.
(Optional) Logs B-channel status messages. This keyword is available only for integrated services digital network (ISDN) serial interfaces.
dchan
(Optional) Logs D-channel status messages. This keyword is available only for ISDN serial interfaces.
nfas
(Optional) Logs non-facility associated signaling (NFAS) D-channel status messages. This keyword is available only for ISDN serial interfaces.
Command Default
Interface state-change messages are not sent.
Command Modes
Interface configuration (config-if)
Command History
Release
Modification
12.2(14)SX
This command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
This command was modified to support the Supervisor Engine 2.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
To enable system logging of interface state-change events on a specific interface, enter the
loggingeventlink-status command.
Examples
The following example shows how to enable link-status event messaging on an interface:
Router(config-if)# logging event link-status
This example shows how to disable link-status event messaging on an interface:
Router(config-if)# no logging event link-status
logging event subif-link-status
To enable the link-status event messaging on a subinterface, use the
loggingeventsubif-link-status command in interface configuration mode. To disable the link-status event messaging on a subinterface, use the
no form of this command.
loggingeventsubif-link-status
nologgingeventsubif-link-status
Syntax Description
This command has no arguments or keywords.
Command Default
Subinterface state-change messages are not sent.
Command Modes
Interface configuration
Command History
Release
Modification
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
This command is not supported on Cisco 7600 series routers that are configured with a Supervisor Engine 720.
To enable system logging of interface state-change events on a specific subinterface, enter the
loggingeventsubif-link-status command.
To enable system logging of interface state-change events on a specific interface, enter the
loggingeventlink-status command.
To enable system logging of interface state-change events on all interfaces in the system, enter the
loggingeventlink-status command.
Examples
This example shows how to enable the system logging of the interface state-change events on a subinterface:
This example shows how to disable the system logging of the interface state-change events on a subinterface:
Router(config-if)# no logging event subif-link-status
Router(config-if)#
Related Commands
Command
Description
showrunning-config
Displays the status and configuration of the module or Layer 2 VLAN.
logging-events
toprinttypicalT3controllerUpandDownmessageson a Channelized T3 Port Adapter,use the logging-eventscommandin T3 controller configuration mode.UsethenoformofthiscommandtodisableprintingoftheT3controllerUpandDownmessages.
logging-events [detail]
[no] logging-events
Syntax Description
detail
(Optional) Enables printing the reason code when a T3 controller changes from the Up to Down state.
The following example uses the logging-events [detail] command to show the Out-of-Frame (OOF) reason code when the T3 controller changes from an Up state to a Down state:
Router(config-controller)# logging-events detail
*Jun 19 17:47:50: %CONTROLLER-5-DOWNDETAIL: Controller T3 4/1, changed state to down due to OOF
Related Commands
Command
Description
t1logging-events
PrintsthetypicalT1controllerUpandDownmessages on a channelized T3 port adapter.
logging-events (T1-E1 controller)
To show the controller state change and alarms on a controller, use the
logging-eventscommand in controller configuration mode. To turn off controller state change reporting, use the
no form of the command.
logging-eventsdetail
nologging-events
Syntax Description
detail
Alarm along with the controller state change.
Command Default
Logging-events is the default.
Command Modes
Controller configuration
Command History
Release
Modification
12.2(18)SXE
This command was introduced to support SPAs on the Cisco 7600 series router and Catalyst 6500 series switch.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
Use the
logging-eventscommand to show the state change and alarms on a controller on an 8-Port Channelized T1/E1 Serial SPA.
Examples
The following shows enabling the logging-events command.
Configures a T1, E1, or T3 controller and enters controller configuration mode.
showcontroller
Displays controller configuration.
loopback (CEM)
To set the loopback method for testing a T1, E1, or serial CEM interface, use the loopback command in controller configuration or CEM configuration mode. To remove any existing loopback, use the no form of this command.
Cisco NM-CEM-4SER
loopback
{ local | network }
noloopback
Cisco NM-CEM-4TE1
loopback
{ local
{ payload | line } | network }
noloopback
Syntax Description
local
Places the interface into local loopback mode and creates a loopback wherein information received from the locally-attached customer premises equipment (CPE) is transmitted back to the locally-attached CPE.
payload--(Used only if a local loopback is specified for a T1/E1 channel) Creates a loopback of only the data in individual time slots. In this mode, framing bits are terminated and then regenerated instead of being looped back. This mode is not available if the port is configured for framingunframed.
line--(Used only if a local loopback is specified for a T1/E1 channel) Creates a full physical layer loopback of all bits, including data and framing bits.
network
Creates a loopback wherein data received over the network from the remote CPE is transmitted back to the remote CPE.
Command Default
No loopback is configured for a CEM interface.
Cisco NM-CEM-4SER
CEM configuration
Controller configuration
Command History
Release
Modification
12.3(7)T
This command was introduced.
Usage Guidelines
Use this command to create a loopback for a CEM interface. You can use a loopback to test for equipment malfunction caused by the interface.
The NM-CEM-4TE1 does not respond to loopback requests initiated by the CPE, locally attached or remote, using the extended super frame (ESF) Facility Data Link (FDL) mechanism or by any other mechanism.
The NM-CEM-4SER does not respond to any form of loopback request initiated by the locally attached or remote CPE on the Local Loop (LL) or Remote Loop (RL) control leads. Nor does the NM-CEM-4SER respond to any form of loopback request initiated by the locally attached or remote CPE using in-band loopback codes.
Examples
The following example shows how to create a loopback on a CEM T1/E1 interface so that data received from a remote CPE is transmitted back to the remote CPE on the network.
Router(config-controller)# loopback network
The following example shows how to create a loopback of data in individual time slots on a CEM T1/E1 interface. Data received from a locally attached CPE will be sent back to the locally attached CPE.
Router(config-controller)# loopback local payload
The following example shows how to create a loopback on a serial CEM channel so that data received from a remote CPE is transmitted back to the remote CPE on the network.
Router(config-cem)# loopback network
Related Commands
Command
Description
cem
Enters circuit emulation configuration mode.
controller
Enters controller configuration mode.
loopback (DSL controller)
To test the controller and configure the core loopback, use the loopback(DSLController)command in controller configuration mode. To remove the loopback interface, use the no form of this command.
loopback
{ analog | digital }
noloopback
Syntax Description
analog
Loops the circuit at the analog hybrid to verify the analog loopback hardware to the analog hybrid.
digital
Loops the circuit at the framer to verify the hardware to the framer.
Command Default
No default behavior or values.
Command Modes
Controller configuration
Command History
Release
Modification
12.3(4)XD
This command was introduced on Cisco 2600 series and Cisco 3700 series routers.
12.3(4)XG
This command was integrated into Cisco IOS Release 12.3(4)XG on the Cisco 1700 series routers.
12.3(7)T
This command was integrated in Cisco IOS Release 12.3(7)T on Cisco 2600 series, Cisco 3631, and Cisco 3700 series routers.
12.3(11)T
This command was integrated into Cisco IOS Release 12.3(11)T on Cisco 2800 series and Cisco 3800 series routers.
12.3(14)T
This command was integrated into Cisco IOS Release 12.3(14)T on Cisco 1800 series routers.
Usage Guidelines
Analog and digital loopbacks are local loopbacks. Digital loopbacks loop the circuit at the framer to verify the hardware to the framer, and analog loopbacks loop the circuit at the analog hybrid to verify the analog loopback hardware to the analog hybrid. The controller must be shut down before loopback can be configured.
Examples
If the controller is still up, the router will prompt you to turn the controller off as shown in this example:
Router(config-controller)# loopbackanalog
Please shut down the xDSL controller
Router(config-controller)# loopbackdigital
Please shut down the xDSL controller
The following example shows the configuration of a loopback digital interface:
Router(config-controller)# loopback digital
Please shut down the xDSL controller
Router(config-controller)# shutdown
Router(config-controller)#
00:59:50: %CONTROLLER-5-UPDOWN: Controller DSL 0/0, changed state to
administratively down
Router(config-controller)#
Router(config-controller)# loopback digital
Router(config-controller)# no shutdown
Apr 23 06:59:01.435: DSL 0/0 controller Link up! line rate: 4608 Kbps
o
00:59:59: %CONTROLLER-5-UPDOWN: Controller DSL 0/0, changed state to up
Router(config-controller)#end
Router# show controllers dsl 0/0
DSL 0/0 controller UP
Local Digital loopback is running
Globespan xDSL controller chipset
DSL mode: SHDSL Annex B
Frame mode: Utopia
Configured Line rate: 4608Kbps
Line Re-activated 4 times after system bootup
LOSW Defect alarm: ACTIVE
CRC per second alarm: ACTIVE
Line termination: CO
FPGA Revision: 0xA7
Line 0 statistics
Current 15 min CRC: 679
Current 15 min LOSW Defect: 8
Current 15 min ES: 5
Current 15 min SES: 5
Current 15 min UAS: 397
Previous 15 min CRC: 0
Previous 15 min LOSW Defect: 0
Previous 15 min ES: 0
Previous 15 min SES: 0
Previous 15 min UAS: 0
Line 1 statistics
Current 15 min CRC: 577
Current 15 min LOSW Defect: 8
Current 15 min ES: 7
Current 15 min SES: 4
Current 15 min UAS: 411
Previous 15 min CRC: 0
Previous 15 min LOSW Defect: 0
Previous 15 min ES: 0
Previous 15 min SES: 0
Previous 15 min UAS: 0
Line-0 status
Chipset Version: 1
Firmware Version: A29733
Modem Status: un checked mode, Status 83
Last Fail Mode: No Failure status:0x0
Line rate: 2312 Kbps
Framer Sync Status: In Sync
Rcv Clock Status: In the Range
Loop Attenuation: 0.0 dB
Transmit Power: 13.5 dB
Receiver Gain: 936.8420 dB
SNR Sampling: 16.960 dB
Line-1 status
Chipset Version: 1
Firmware Version: A29733
Modem Status: un checked mode, Status 83
Last Fail Mode: No Failure status:0x0
Line rate: 2312 Kbps
Framer Sync Status: In Sync
Rcv Clock Status: In the Range
Loop Attenuation: 0.0 dB
Transmit Power: 13.5 dB
Receiver Gain: 936.8420 dB
SNR Sampling: 16.3590 dB
Dying Gasp: Present
Related Commands
Command
Description
show interfaces loopback
Displays information about the loopback interface.
loopback (E3 controller)
To loop an entire E3 line toward the line and back toward the router, use the loopbackcommand in controller configuration mode. To remove the loop, use the no form of this command.
loopback
{ local | network
{ line | payload } }
noloopback
Syntax Description
local
Loops the data back toward the router and sends an AIS signal out toward the network. This is the default.
networklinepayload
Sets the loopback toward the network either before going through the framer (line) or after going through the framer (payload).
Command Default
local
Command Modes
Controller configuration
Command History
Release
Modification
11.3
This command was introduced.
12.2(11)YT
This command was integrated into Cisco IOS Release 12.2(11)YT and implemented on the following platforms for E3: Cisco 2650XM, Cisco 2651XM, Cisco 2691, Cisco 3660 series, Cisco 3725, and Cisco 3745 routers.
12.2(15)T
This command was integrated into Cisco IOS Release 12.2(15)T.
Usage Guidelines
Use this command for troubleshooting purposes. To verify that a loopback is configured on the interface, use the showcontrollerse3EXEC command. Note that line loopback is available only in C-bit parity mode.
Examples
The following example shows how to configure the controller located in slot 1, port 0 for a local loopback:
Router(config)# controller e3 1/0
Router(config-controller)# loopback local
Related Commands
Command
Description
showcontrollerse3
Displays information about the E3 controllers.
loopback (interface)
To diagnose equipment malfunctions between the interface and device, use the
loopbackcommand in interface configuration mode. To disable the test, use the
no form of this command.
loopback
noloopback
Syntax Description
This command has no arguments or keywords.
Command Default
Disabled
Command Modes
Interface configuration
Command History
Release
Modification
10.0
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Loopback on HSSI Cards
On High-Speed Serial Interface (HSSI) cards, the loopback function configures a two-way internal and external loop on the HSA applique of the specific interface.
Loopback on MCI and SCI Serial Interface Cards
On MCI and SCI serial interface cards, the loopback functions when a CSU/DSU or equivalent device is attached to the router or access server. Theloopback command loops the packets through the CSU/DSU to configure a CSU loop, when the device supports this feature.
Loopback on MCI and MEC Ethernet Cards
On the MCI and MEC Ethernet cards, the interface receives back every packet it sends when the
loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Loopback on CSC-FCI FDDI Cards
On the CSC-FCI FDDI card, the interface receives back every packet it sends when the
loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Loopback on Token Ring Interface Cards
On all Token Ring interface cards (except the 4-megabit CSC-R card), the interface receives back every packet it sends when the
loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Active Loopback Interfaces
To show interfaces currently in loopback operation, use the
showinterfacesloopback EXEC command.
Note
Loopback does not work on an X.21 DTE because the X.21 interface definition does not include a loopback definition.
Examples
The following example configures the loopback test on Ethernet interface 4:
Configures an interface to inform the system it is down when loopback is detected.
showinterfacesloopback
Displays information about the loopback interface.
loopback (J1 controller )
To set the loopback method for testing the J1 interface, use the loopback command in controller configuration mode. To turn off loopback, use the no form of this command. This command should be used for testing purposes only.
loopback
{ local | line | isolation }
noloopback
{ local | line | isolation }
Syntax Description
local
Places the interface into local loopback mode.
line
Places the interface into external loopback mode at the line level.
isolation
Places the interface into both local and line loopback mode.
Command Default
No loopback is configured.
Command Modes
Controller configuration
Command History
Release
Modification
11.3 MA
This command was implemented on the Cisco MC3810.
12.0(5)T and 12.0(7)XR
The command was implemented on the Cisco 2600 and Cisco 3600 series.
12.0(5)XE
The command was implemented on the Cisco 7200 and Cisco 7500 series.
12.1(1)T
The command was implemented on the Cisco 2600 series.
12.2(8)T
The command was implemented on the Cisco 2600 and Cisco 3600 series.
Examples
The following example establishes a loopback of the incoming J1 signal on controller J1 3/0:
Router(config)# controller j1 3/0
Router(config-controller)# loopback line
loopback (PA-MC-8TE1+ port adapter)
To enable loopback testing of data for the PA-MC-8TE1+ port adapter, use the loopback command in interface configuration mode. To disable loopback testing, use the no form of this command.
loopback
[ internal | line ]
noloopback
[ internal | line ]
Syntax Description
internal
(Optional) Loops any data received at the PA-MC-8TE1+ port adapter’s network interface back into the PA-MC-8TE1+ port adapter.
line
(Optional) Loops any data received at the PA-MC-8TE1+ port adapter’s network interface back into the network.
Command Default
Loopback mode is not enabled.
Command Modes
Interface configuration
Command History
Release
Modification
12.2(13)T
This command was introduced.
Examples
In the following example, a loopback is set for the PA-MC-8TE1+ port adapter in slot 2:
Router(config)# interface 2/0
Router(config-if)# loopback line