-
Interface and Hardware Component Command Reference for the Cisco NCS 6000 Series Routers
-
Preface
-
Ethernet Interface Commands \n\t
-
Ethernet OAM Commands
-
Global Interface Commands
-
Link Bundling Commands
-
Management Ethernet Interface Commands
-
Null Interface Commands
-
Packet-over-SONET Interface Commands
-
PPP Commands
-
VLAN Subinterface Commands
-
10-Gigabit Ethernet\n\t WAN PHY Controller Commands
-
Index
-
Feedback
Contents
Global Interface Commands
bandwidth (global)
To configure the bandwidth of an interface, use the bandwidth command in interface configuration mode.
Syntax Description
rate
Amount of bandwidth to be allocated on the interface, in Kilobits per second (kbps). Range is from 0 through 4294967295.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Note
To obtain the default bandwidth for a specific interface, use the show interfaces command after you first bring up the interface. The default interface bandwidth is displayed in the show interfaces command output.
Task ID
Examples
This example shows how to configure the bandwidth on a Gigabit Ethernet interface:
RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router# interface GigabitEthernet 0/4/1/0 RP/0/RP0/CPU0:router# bandwidth 4000000clear interface
Syntax Description
type
Interface type. For more information, use the question mark (?) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark (?) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
For the interface-path-id argument, use these guidelines:
- If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:
- If specifying a virtual interface, the number range varies, depending on interface type.
Task ID
Examples
This example shows how to use the clear interface command to clear the loopback interface 2:
RP/0/RP0/CPU0:router# clear interface loopback 2dampening
To limit propagation of transient or frequently changing interface states on Interface Manager (IM) clients, turn on event dampening by using the dampening command in interface configuration mode. To turn dampening off, use the no form of this command.
dampening [ half-life [ reuse suppress max-suppress-time ] ]
no dampening [ half-life [ reuse suppress max-suppress-time ] ]
Syntax Description
half-life
(Optional) Time (in minutes) after which a penalty is decreased. Once the interface has been assigned a penalty, the penalty is decreased by half after the half-life period. The process of reducing the penalty happens every 5 seconds. The range of the half-life period is 1 to 45 minutes. The default is 1 minute.
reuse
(Optional) Penalty value below which a stable interface is unsuppressed. Range is from 1 through 20000. Default value is 750.
suppress
(Optional) Limit at which an interface is suppressed when its penalty exceeds that limit. Range is from 1 through 20000, and must be greater than the reuse threshold. The default value is 2000.
max-suppress-time
(Optional) Maximum time (in minutes) that an interface can be suppressed. This value effectively acts as a ceiling that the penalty value cannot exceed. Default value is four times the half-life period.
Command Default
Dampening is turned off by default. When you use the dampening command, the following default values are enabled for any optional parameters that you do not enter:
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Event dampening suppresses a constantly unstable interface until it remains stable for a period of time. Enabling dampening on an interface that already has dampening configured has the effect of resetting the penalty associated with that interface to zero. The reuse threshold must always be less than the suppress threshold.
Consider the following guidelines when configuring event dampening:
- Configuring dampening on both a subinterface and its parent is usually unnecessary because their states are almost always the same and dampening would be triggered at the same time on each interface.
- If all subinterfaces require dampening, then apply dampening to the main interface only. Applying configuration to large numbers of subinterfaces requires an abundance of memory and increases the time required to process the configuration during boot and failover.
- When dampening is enabled, an interface has a penalty value associated with it. The value starts at 0 and is increased by 1000 whenever the underlying state of the interface changes from up to down.
- The penalty value decreases exponentially while the interface state is stable. If the penalty value exceeds a configured suppress threshold, then the state of the interface is suppressed and IM will not notify upper layers of further state transitions. The suppressed state remains until the penalty value decreases past a configured reuse threshold.
Task ID
Examples
This example shows how to enable dampening with default values on an interface:
RP/0/RP0/CPU0:router(config)# interface POS 0/4/0/0 RP/0/RP0/CPU0:router(config-if))# dampeningmtu
To adjust the maximum transmission unit (MTU) value for packets on the interface, use the mtu command in interface configuration mode. To return the interface to the default MTU for the interface type, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the mtu command to set a specific MTU value for an interface, or use the no mtu command to return the interface to the default MTU value for that interface type. The MTU value can be increased or decreased using the mtu command, subject to minimum and maximum MTU limits for the interface type.
If the MTU value is not configured, then each interface will have a default MTU value that is specific to the interface type. The default MTU value is generally the largest Layer 2 frame size possible for the interface type.
The default/configured MTU value on an atm interface includes the L2 header.
The MTU size consists of L2 header that includes either SNAP(8bytes)/MUX(0)/NLPID(2) header or the AAL5 SDU. The AAL5 SDU includes the L3 datagram and the optional Logical Link Control/Subnetwork Access Protocol (LLC/SNAP) header.
The Ethernet interface is the Layer 3 datagram plus 14 bytes. For ATM main interface, the MTU is L3 datagram + 0 bytes.
For ATM L3 sub interface, mtu is as follows:
- SNAP - L3 datagram + 8 bytes
- NLPID - L3 datagram + 2 bytes
- MUX - L3datagram + 0 bytes
- When no pvc is configured under sub interface - L3datagram + 0 bytes
Note
All serial links in a Multilink Point-to-Point Protocol (MLPPP) bundle or a Multilink Frame Relay (MFR) bundle inherit the default MTU value from the multilink bundle. If a serial interface has a nondefault MTU value, the Cisco IOS XR software blocks that serial interface from being added to an MLPPP or MFR bundle. Therefore, you must not configure the MTU value on a serial interface until you have added that serial interface to an MLPPP or MFR bundle.
You can use the show interfaces command to determine if the MTU value has been changed. The show interfaces command output displays the MTU size for each interface in the MTU (byte) field.
Note
You can use the show interfaces command to determine if the MTU value has been changed. The show interfaces command output displays the MTU size for each interface in the MTU (byte) field. Note that the MTU size that is displayed includes the Layer 2 header bytes used for each encapsulation type.
Note
Changing the MTU on an interface triggers a change on the protocols and capsulations configured on that interface, although some protocol-specific configurations can override the interface MTU. For example, specifically changing the interface MTU configuration does not affect the IP MTU configuration, but may affect the resulting MTU on that node.
Task ID
Examples
In the following example, the MTU value for all interfaces is verified. The MTU value is shown in the next-to-last column:
RP/0/RP0/CPU0:router# show interfaces all brief Intf Intf LineP Encap MTU BW Name State State Type (byte) (Kbps) -------------------------------------------------------------------------------- Nu0 up up Null 1500 Unknown PO6/0/0/0 up up HDLC 4474 2488320 PO6/0/0/1 up up HDLC 4474 2488320 PO6/0/0/2 admin-down admin-down HDLC 4474 2488320 PO6/0/0/3 admin-down admin-down HDLC 4474 2488320 Mg0//CPU0/0 up up ARPA 1514 100000 RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router(config)# interface POS 6/0/0/0 RP/0/RP0/CPU0:router(config-if)# mtu 1000After the mtu command is used to decrease the MTU Layer 2 frame size for the POS interface on 6/0/0/0 to 1000 bytes, the show interfaces all brief command is used again to verify that the MTU Layer 2 frame size has been changed:
RP/0/RP0/CPU0:router# show interfaces all brief Intf Intf LineP Encap MTU BW Name State State Type (byte) (Kbps) -------------------------------------------------------------------------------- Nu0 up up Null 1500 Unknown PO6/0/0/0 up up HDLC 1000 2488320 PO6/0/0/1 up up HDLC 4474 2488320 PO6/0/0/2 admin-down admin-down HDLC 4474 2488320 PO6/0/0/3 admin-down admin-down HDLC 4474 2488320 Mg0//CPU0/0 up up ARPA 1514 100000show im dampening
To display the state of all interfaces on which dampening has been configured, use the show im dampening command in EXEC mode.
Syntax Description
interface type
(Optional) Interface type. For more information, use the question mark (?) online help function.
ifhandle handle
(Optional) Identifies the caps node whose Interface Manager (IM) dampening information you want to display.
Command Default
If you do not specify an interface, then the system displays brief details about all dampened interfaces.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
If you do not specify an interface, then the system displays brief details about all dampened interfaces.
The physical hardware (layer 1) is not the only part of an interface that can change state. L2 keepalive failure event is one of the many instances that can have a similar impact on routing protocols despite the underlying interface state staying UP. To take account of such events, when dampening is configured on an interface, it is applied independently to every layer. They all use the same parameters as the interface but they have their own penalty value which is incremented when that layer changes state.
Capsulations that may be dampened in this way include these:
- L2 basecaps, such as HDLC and PPP, which may flap if keepalives are not received due to events such as intermittent packet loss.
- L3 capsulations (for example ipv4, ipv6). These may be brought down if another link has a conflicting IP address configured.
- Other locations where negotiation takes place with a peer router, as in the case of PPP control protocols such as IPCP. If the negotiation fails, then the caps is brought down.
Task ID
Examples
The following example shows the output from the show im dampening command issued with default values:
RP/0/RP0/CPU0:router(config)# interface POS 0/4/0/3 RP/0/RP0/CPU0:router(config-if)# no shutdown RP/0/RP0/CPU0:router(config-if)# dampening RP/0/RP0/CPU0:router# show im dampening Interface Proto Caps Penalty Suppressed --------- ----- ---- ---------------- POS0/4/0/3 0 0 0 NO RP/0/RP0/CPU0:router# show im dampening interface POS 0/4/0/3 POS0/4/0/3 (0x05000d00) Dampening enabled: penalty 0, not suppressed underlying state: Up half_life: 1 reuse: 750 suppress: 3000 max-suppress-time: 4 restart-penalty: 0 RP/0/RP0/CPU0:router# show interfaces POS 0/4/0/3 POS0/4/0/3 is up, line protocol is down Dampening enabled: penalty 0, not suppressed half_life: 1 reuse: 750 suppress: 3000 max-suppress-time: 4 restart-penalty: 0 Hardware is Packet-over-SONET Description: ensoft-gsr5 POS 4\2 Internet address is Unknown MTU 4474 bytes, BW 155520 Kbit reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, crc 16, controller loopback not set, keepalive set (10 sec) Last clearing of "show interface" counters never 30 second input rate 0 bits/sec, 0 packets/sec 30 second output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 total input drops 0 drops for unrecognized upper-level protocol Received 0 broadcast packets, 0 multicast packets 0 runts, 0 giants, 0 throttles, 0 parity 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 48 packets output, 1504 bytes, 0 total output drops Output 0 broadcast packets, 0 multicast packets 0 output errors, 0 underruns, 0 applique, 0 resets 0 output buffer failures, 0 output buffers swapped outThis sample output shows a POS interface with PPP basecaps and IPCP. The subsequent output for show im dampening interface <ifname> contains a table of any capsulations which have their own penalty as shown below:
RP/0/RP0/CPU0:router# show im dampening Interface Protocol Capsulation Pen Sup --------------------------- ------------------ -------------------- ----- --- GigabitEthernet0/0/0/0 629 NO GigabitEthernet0/0/0/1 2389 YES POS0/2/0/0 0 NO POS0/2/0/0 <base> ppp 0 NO POS0/2/0/0 ipv4 ipcp 0 NO RP/0/RP0/CPU0:router# show im dampening interface TenGigaE 0/1/0/0 TenGigE 0/1/0/0 (0x01180020) Dampening enabled: Penalty 1625, SUPPRESSED (42 secs remaining) Underlying state: Down half-life: 1 reuse: 1000 suppress: 1500 max-suppress-time: 4 restart-penalty: 0 Protocol Capsulation Pen Suppression U-L State -------------- ------------------ ----- --------------------- ------------- ipv6 ipv6 1625 YES 42s remaining Down
Note
When dampening is configured on an interface it is also applied independently to all capsulations on that interface. For example, the ppp or hdlc basecaps state can flap even while the interface stays up and if keepalives fail. The show im dampening interface command contains one line for each such capsulation as well as the interface itself as shown for the POS interface in the previous example.
Table 1 show im dampening Field Descriptions Field
Description
Dampening
Indicates the dampening state and penalty value: not suppressed, suppressed.
underlying state
Underlying state of the interface: up, down, administratively down (if an interface has been configured to be “shutdown”).
half_life
This is the time (in minutes) at which the penalty on the interface would be half that of the original penalty (of 1000) when the interface transitions from UP to DOWN. It ranges from 1 to 45 minutes and the default is 1 minute.
reuse
Penalty value below which a stable interface is unsuppressed. It ranges from 1 to 20000 and the default value is 750.
suppress
Limit at which an unstable interface is suppressed when the penalty value exceeds the suppress value. It ranges from 1 to 20000 and the default value is 2000.
max-suppress-time
Maximum time (in minutes) that an interface can be suppressed. The default is 4 minutes.
restart-penalty
Penalty assigned to the interface when it flaps.
show interfaces
To display statistics for all interfaces configured on the router or for a specific node, use the show interfaces command in EXEC mode.
show interfaces [ type interface-path-id | all | local | location node-id ] [ accounting | brief | description | detail | summary ]
Syntax Description
type
(Optional) Specifies the type of interface for which you want to display statistics. For more information, use the question mark (?) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark (?) online help function.
all
(Optional) Displays interface information for all interfaces This is the default.
local
(Optional) Displays interface information for all interfaces in the local card.
location node-id
(Optional) Displays information about all interfaces on the specified node. The node-id argument is entered in the rack/slot/module notation.
accounting
(Optional) Displays the number of packets of each protocol type that have been sent through the interface.
brief
(Optional) Displays brief information of each interface (one line per interface).
description
(Optional) Displays the status, protocol, and description of each interface (one line per interface).
detail
(Optional) Displays detailed information about each interface. This is the default.
summary
(Optional) Displays a summary of interface information by interface type.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
For the interface-path-id argument, use the following guidelines:
- If specifying a physical interface, the naming notation is rack/slot/module/port. The slash between values is required as part of the notation. An explanation of each component of the naming notation is as follows:
- If specifying a virtual interface, the number range varies, depending on interface type.
The show interfaces command displays statistics for the network interfaces. The resulting display shows the interface processors in slot order.
For example, if you type the show interfaces command without an interface type, you receive information for all the interfaces installed in the networking device. Only by specifying the interface type, slot, and port arguments can you display information for a particular interface.
If you enter a show interfaces command for an interface type that has been removed from the networking device, an error message is displayed: “Interface not found.”
The output displayed depends on the network for which an interface has been configured.
Note
The 5-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average is within 2 percent of the instantaneous rate of a uniform stream of traffic over that period.
Task ID
Examples
The following example shows the output from the show interfaces command. The output displayed depends on the type and number of interface cards in the networking device.
RP/0/RP0/CPU0:router# show interfaces tenGigE 0/0/0/1 TenGigE0/0/0/1 is administratively down, line protocol is administratively down Hardware is TenGigE, address is 0800.4539.d909 (bia 0800.4539.d909) Description: user defined string Internet address is Unknown MTU 1514 bytes, BW 10000000 Kbit reliability 255/255, txload 0/255, rxload 0/255 Encapsulation ARPA, Full-duplex, 10000Mb/s, LR output flow control is off, input flow control is off loopback not set ARP type ARPA, ARP timeout 01:00:00 Last clearing of "show interface" counters never 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 total input drops 0 drops for unrecognized upper-level protocol Received 0 broadcast packets, 0 multicast packets 0 runts, 0 giants, 0 throttles, 0 parity 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 0 packets output, 0 bytes, 0 total output drops Output 0 broadcast packets, 0 multicast packets 0 output errors, 0 underruns, 0 applique, 0 resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitionsIn the following sample output, instance 1 is specified on a Packet-over-SONET/SDH (POS) card:
RP/0/RP0/CPU0:router# show interfaces POS 0/1/0/1 POS0/1/0/1 is administratively down, line protocol is administratively down Hardware is Packet over SONET Internet address is n.n.n.n/n MTU 4474 bytes, BW 9953280 Kbit reliability 255/255, txload 0/255, rxload 0/255 Encapsulation HDLC, crc 32, controller loopback not set, keepalive not set Last clearing of "show interface" counters never 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 total input drops 0 drops for unrecognized upper-level protocol Received 0 broadcast packets, 0 multicast packets 0 runts, 0 giants, 0 throttles, 0 parity 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 0 packets output, 0 bytes, 0 total output drops Output 0 broadcast packets, 0 multicast packets 0 output errors, 0 underruns, 0 applique, 0 resets 0 output buffer failures, 0 output buffers swapped outThe following example shows sample output for ATM subinterface 0/4/2/0/1.1:
RP/0/RP0/CPU0:router# show interfaces ATM0/4/2/0/1.1 ATM0/4/2/0/1.1 is up, line protocol is up Interface state transitions: 1 Hardware is ATM network sub-interface(s) Description: Connected to PE22_C12406 ATM 0/4/0/0/1.1 Internet address is 10.212.4.21/24 MTU 4486 bytes, BW 1544 Kbit reliability Unknown, txload Unknown, rxload Unknown Encapsulation AAL5/SNAP, controller loopback not set, Last clearing of "show interface" counters Unknown Datarate information unavailable. Interface counters unavailable.The following example shows bundle member links whose link interface status is “err-disable” and line protocol state is “admin-down” after the bundle interface has been administratively shut down using the shutdown command:
RP/0/RP0/CPU0:router# show interfaces brief Thu May 6 06:30:55.797 DST Intf Intf LineP Encap MTU BW Name State State Type (byte) (Kbps) -------------------------------------------------------------------------------- BE16 admin-down admin-down ARPA 9216 1000000 BE16.160 up up 802.1Q VLAN 9220 1000000 BE16.161 up up 802.1Q VLAN 9220 1000000 BE16.162 up up 802.1Q VLAN 9220 1000000 BE16.163 up up 802.1Q VLAN 9220 1000000 Lo0 up up Loopback 1500 Unknown Nu0 up up Null 1500 Unknown tt44190 up up TUNNEL 1500 Unknown tt44192 up up TUNNEL 1500 Unknown tt44194 up up TUNNEL 1500 Unknown tt44196 up up TUNNEL 1500 Unknown Gi0/1/0/0 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/1 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/2 up up ARPA 9014 1000000 Gi0/1/0/3 up up ARPA 9014 1000000 Gi0/1/0/3.160 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/3.161 up up 802.1Q VLAN 9018 1000000 Gi0/1/0/3.185 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/3.189 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/3.215 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/4 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/5 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/6 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/7 up up ARPA 9014 1000000 Gi0/1/0/7.185 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/7.187 up up 802.1Q VLAN 9014 1000000 Gi0/1/0/7.189 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/7.210 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/7.211 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/7.215 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/8 up up ARPA 9014 1000000 Gi0/1/0/9 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/10 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/11 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/12 up up ARPA 9216 1000000 Gi0/1/0/13 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/14 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/15 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/16 up up ARPA 9216 1000000 Gi0/1/0/17 up up ARPA 1514 1000000 Gi0/1/0/18 up up ARPA 9216 1000000 Gi0/1/0/19 up up ARPA 9014 1000000 Gi0/1/0/19.2127 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/19.2130 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/20 up up ARPA 9014 1000000 Gi0/1/0/20.2125 up up 802.1Q VLAN 9022 1000000 Gi0/1/0/21 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/22 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/23 up up ARPA 9216 1000000 Gi0/1/0/24 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/25 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/26 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/27 up up ARPA 1514 1000000 Gi0/1/0/28 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/29 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/30 up up ARPA 9014 1000000 Gi0/1/0/30.215 up up 802.1Q VLAN 9018 1000000 Gi0/1/0/31 up up ARPA 9014 1000000 Gi0/1/0/32 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/33 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/34 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/35 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/36 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/37 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/38 admin-down admin-down ARPA 1514 1000000 Gi0/1/0/39 admin-down admin-down ARPA 1514 1000000 Te0/4/0/0 err-disable admin-down ARPA 1514 10000000 Te0/4/0/1 err-disable admin-down ARPA 1514 10000000 Te0/4/0/2 err-disable admin-down ARPA 1514 10000000 Te0/4/0/3 err-disable admin-down ARPA 1514 10000000 Te0/4/0/4 err-disable admin-down ARPA 1514 10000000 Te0/4/0/5 err-disable admin-down ARPA 1514 10000000 Te0/4/0/6 err-disable admin-down ARPA 1514 10000000 Te0/4/0/7 err-disable admin-down ARPA 1514 10000000 Te0/6/0/0 admin-down admin-down ARPA 1514 10000000 Te0/6/0/1 admin-down admin-down ARPA 1514 10000000 Te0/6/0/2 admin-down admin-down ARPA 1514 10000000 Te0/6/0/3 admin-down admin-down ARPA 1514 10000000
Table 2 show interfaces Field Descriptions Field
Description
Interface name
Displays the name of the current interface. For example, POS0/1/0/1.
Interface state
Displays the state of the interface. For example, the interface is in the administratively up state.
Interface state transitions
Displays the number of times since the last reload that the interface transitioned from the administratively up state to the administrative down state and from the administratively down state to the administratively up state.
line protocol state
Displays the state of the Layer 2 line protocol. This field may be different from the interface state if, for example, a keepalive failure has brought down the Layer 2.
Note The line protocol state is not the same as the protocol state displayed in the show ip interfaces command, because it is the state of Layer 2 (media) rather than Layer 3 (IP protocol).
Hardware
Displays the current hardware type.
Internet address is n.n.n.n/n
Displays the Layer 2 address (MAC address for Ethernet interfaces).
Note Enter the mac-address command to configure the hardware address.
bia
Displays the burned-in address (BIA) for the interface. The BIA is the default L2 (MAC) address for the interface.
Note The BIA is not configurable.
description
Displays the user-defined string that is associated with the interface.
Note Enter the description command to configure the description associated with the interface.
Internet Address
Displays the Layer 3 (IP) address for the interface.
Note Enter the ipv4 address command to configure the internet address for the interface.
MTU
Displays the maximum transmission unit (MTU) for the interface. The MTU is the maximum packet size that can be transmitted over the interface.
Note The MTU field indicates the interface MTU. Enter the mtu command to configure a lower MTU value at the Layer 3 level.
BW
Displays the bandwidth of the interface in kbps.
reliability
Displays the proportion of packets that are not dropped and do not have errors.
Note The reliability is shown as a fraction of 255.
txload
Indicates the traffic flowing out of the interface as a proportion of the bandwidth.
Note The txload is shown as a fraction of 255.
rxload
Indicates the traffic flowing into the interface as a proportion of the bandwidth.
Note The rxload is shown as a fraction of 255.
Encapsulation
Layer 2 encapsulation installed on the interface.
CRC
Indicates the length of the cyclic redundancy check (CRC), in bytes.
Note The CRC is not present for all interface types.
Note Enter the pos crc command to configure the CRC.
loopback or controller loopback
Indicates whether the hardware has been configured to be looped back.
Note Enter the loopback command to configure the loopback or controller loopback.
keepalive
Displays the configured keepalive value, in seconds.
Note Enter the keepalive command to configure the value of the keepalive field.
Note The keepalive field may not be present if it is not applicable to the interface type.
Duplexity
Displays the duplexity of the link.
Note This field is present only for shared media.
Note For some interface types, you can configure the duplexity by entering the full-duplex and half-duplex commands.
Speed
Speed and bandwidth of the link in Mbps. This field is present only when other parts of the media info line are also displayed (see duplexity and media type).
Media Type
Media type of the interface.
output flow control
Whether output flow control is enabled on the interface.
input flow control
See output flow control.
ARP type
Address Resolution Protocol (ARP) type used on the interface. This value is not displayed on interface types that do not use ARP.
ARP timeout
ARP timeout in hours:mins:secs. This value is configurable using the arp timeout command.
Last clearing of counters
Time since the following counters were last cleared using the clear counters exec command in hours:mins:secs.
5 minute input rate
Average number of bits and packets received per second in the last 5 minutes. If the interface is not in promiscuous mode, it senses network traffic that it sends and receives (rather than all network traffic).
Note The 5-minute period referenced in the command output is a load interval that is configurable under the interface. The default value is 5 minutes.
Note The 5-minute input should be used only as an approximation of traffic per second during a given 5-minute period. This rate is exponentially weighted average with a time constant of 5 minutes. A period of four time constants must pass before the average is within two percent of the instantaneous rate of a uniform stream of traffic over that period.
5 minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes. If the interface is not in promiscuous mode, it senses network traffic that it sends and receives (rather than all network traffic).
Note The 5-minute period referenced in the command output is a load interval that is configurable under the interface. The default value is 5 minutes.
Note The 5-minute output should be used only as an approximation of traffic per second during a given 5-minute period. This rate is exponentially weighted average with a time constant of 5 minutes. A period of four time constants must pass before the average is within two percent of the instantaneous rate of a uniform stream of traffic over that period.
packets input
Number of packets received on the interface that were successfully delivered to higher layers.
bytes input
Total number of bytes successfully received on the interface
total input drops
Total number of packets that were dropped after they were received. This includes packets that were dropped due to configured quality of service (QoS) or access control list (ACL) policies. QoS drops include policer drops, WRED drops, and tail drops. This does not include drops due to unknown Layer 3 protocol.
drops for unrecognized upper-level protocol
Total number of packets that could not be delivered because the necessary protocol was not configured on the interface.
Received broadcast packets
Total number of Layer 2 broadcast packets received on the interface. This is a subset of the total input packet count.
Received multicast packets
Total number of Layer 2 multicast packets received on the interface. This is a subset of the total input packet count.
runts
Number of received packets that were too small to be handled. This is a subset of the input errors count.
giants
Number of received packets that were too large to be handled. This is a subset of the input errors count.
throttles
Number of packets dropped due to throttling (because the input queue was full).
parity
Number of packets dropped because the parity check failed.
input errors
Total number of received packets that contain errors and hence cannot be delivered. Compare this to total input drops, which counts packets that were not delivered despite containing no errors.
CRC
Number of packets that failed the CRC check.
frame
Number of packets with bad framing bytes.
overrun
Number of overrun errors experienced by the interface. Overruns represent the number of times that the receiver hardware is unable to send received data to a hardware buffer because the input rate exceeds the receiver's ability to handle the data.
ignored
Total number of ignored packet errors. Ignored packets are those that are discarded because the interface hardware does not have enough internal buffers. Broadcast storms and bursts of noise can result in an increased number of ignored packets.
abort
Total number of abort errors on the interface.
packets output
Number of packets received on the interface that were successfully delivered to higher layers.
bytes output
Total number of bytes successfully received on the interface.
total output drops
Number of packets that were dropped before being transmitted. This includes packets that were dropped due to configured quality of service (QoS), (policer drops, WRED drops, and tail drops).
Received broadcast packets
Number of Layer 2 broadcast packets transmitted on the interface. This is a subset of the total input packet count.
Received multicast packets
Total number of Layer 2 multicast packets transmitted on the interface. This is a subset of the total input packet count.
output errors
Number of times that the receiver hardware was unable to handle received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
underruns
Number of underrun errors experienced by the interface. Underruns represent the number of times that the hardware is unable to transmit data to a hardware buffer because the output rate exceeds the transmitter’s ability to handle the data.
applique
Number of applique errors.
resets
Number of times that the hardware has been reset. The triggers and effects of this event are hardware-specifc.
output buffer failures
Number of times that a packet was not output from the output hold queue because of a shortage of MEMD shared memory.
output buffers swapped out
Number of packets stored in main memory when the output queue is full; swapping buffers to main memory prevents packets from being dropped when output is congested. The number is high when traffic is bursty.
carrier transitions
Number of times the carrier detect (CD) signal of a serial interface has changed state.
shutdown (global)
To disable an interface (to force an interface to be administratively down), use the shutdown command in interface configuration mode. To enable an interface that has been shut down, use the no form of this command.
Command Default
The interface is enabled by default and is disabled only when shutdown is configured.
Note
When you add an interface to the system, or when all the configuration for an interface is lost or deleted, the interface is put in the shutdown state by the system adding the interface.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the shutdown command to move the state of an interface to administratively down, which stops traffic flowing through the interface. This state does not stop other action from happening on the interface such as changes in configuration, protocols, capsulations, and so forth.
The shutdown command also marks the interface as unavailable. To check whether the state of an interface is down, use the show interfaces command in EXEC mode, which displays the current state of the interface. An interface that has been shut down is shown as administratively down in the display from the show interfaces command.
Task ID
Examples
In the following example, POS interface 0/4/0/2 is turned off:
RP/0/RP0/CPU0:router(config)# interface POS 0/4/0/2 RP/0/RP0/CPU0:router(config-if)# shutdown
