Usage Guidelines
OSMs are not supported on Cisco 7600 series routers that are
configured with a Supervisor Engine 32.
IP Address for the Physical Interface
You do not have to disable the IP address that is assigned to a
physical interface that is part of a channel group, but Cisco highly recommends
doing so.
Layer 2 and Layer 3 Port Channels
You can create both Layer 2 and Layer 3 port channels by entering the
interface port-channel command or, when the
channel-group gets its first physical interface assignment. The port channels
are not created at run time, nor are they created dynamically.
You do not have to create a port-channel interface before assigning a
physical interface to a channel group. A port-channel interface is
automatically created when the channel group gets its first physical interface,
if it is not already created.
Propagation of Configuration and Attribute Changes
Any configuration or attribute changes you make to the port-channel
interface are propagated to all interfaces within the same channel group as the
port channel. (for example, configuration changes are also propagated to the
physical interfaces that are not part of the port-channel, but are part of the
channel group.)
The on Keyword
When you use the
onkeyword, a usable EtherChannel exists only when a port group in
on mode is connected to another port group in the on mode.
Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series
Routers
You do not have to create a port-channel interface before assigning a
physical interface to a channel group. A port-channel interface is created
automatically when the channel group gets its first physical interface, if it
is not already created.
Cisco ASR 1000 Series Routers
The Cisco ASR 1000 series router has the following prerequisites and
restriction:
- A port-channel must be
created before member links are assigned to it.
- IP addresses must be
disabled on member links before those links can be included in a port-channel.
- Fast Ethernet interfaces
are not supported.
Cisco Catalyst Switches
The number of valid values for
numberdepends on the software release. For software releases prior to
Cisco IOS Release 12.1(3a)E3, valid values are from 1 to 256; for Cisco IOS
Release 12.1(3a)E3, 12.1(3a)E4, and 12.1(4)E1, valid values are from 1 to 64.
Cisco IOS Release 12.1 E and later releases support a maximum of 64 values
ranging from 1 to 256.
The channel-group number is global and is shared between all the
channeling protocols. If a specific channel number is used for the PAgP-enabled
interfaces of a channel group, that same channel number cannot be used for
configuring a channel that has LACP-enabled interfaces or vice versa.
Entering the
auto or
desirable keyword enables PAgP on the
specified interface; the command will be rejected if it is issued on an
LACP-enabled interface.
The
active and
passive keywords are valid on PAgP-disabled
interfaces only.
You can change the mode for an interface only if it is the only
interface that is designated to the specified channel group.
The
on keyword forces the bundling of the
interface on the channel without any negotiation.
You can manually configure a switch with PAgP on one side and LACP on
the other side in the
on mode.
With the
on mode, a usable EtherChannel exists only
when a port group in
on mode is connected to another port group in
on mode.
If you enter the
channel group command on an interface that is added to a
channel with a different protocol than the protocol you are entering, the
command is rejected.
If the interface belongs to a channel, the
no form of this command is rejected.
All ports in the same channel group must use the same protocol; you
cannot run two protocols on one channel group.
PAgP and LACP are not compatible; both ends of a channel must use the
same protocol.
You can change the protocol at any time, but this change causes all
existing EtherChannels to reset to the default channel mode for the new
protocol.
Configure all ports in an EtherChannel to operate at the same speed
and duplex mode (full duplex only for LACP mode).
All ports in a channel must be on the same DFC-equipped module. You
cannot configure any of the ports to be on other modules.
On systems that are configured with nonfabric-enabled modules and
fabric-enabled modules, you can bundle ports across all modules, but those
bundles cannot include a DFC-equipped module port.
You do not have to create a port-channel interface before assigning a
physical interface to a channel group. A port-channel interface is created
automatically when the channel group gets its first physical interface, if it
is not already created.
You do not have to disable the IP address that is assigned to a
physical interface that is part of a channel group, but it is highly
recommended.
You can create both Layer 2 and Layer 3 port channels by entering the
interface port-channel command or when the channel group
gets its first physical interface assignment. The port channels are not created
at runtime or dynamically.
Any configuration or attribute changes that you make to the
port-channel interface are propagated to all interfaces within the same channel
group as the port channel (for example, configuration changes are also
propagated to the physical interfaces that are not part of the port channel but
are part of the channel group).
When configuring Layer 2 EtherChannels, you cannot put Layer 2 LAN
ports into manually created port-channel logical interfaces.
Only the
on mode is supported when using this command
with GE-WAN ports on the OSM-2+4GE-WAN+ OSM to create QinQ link bundles for
advanced QinQ translation. Also, you cannot use the
channel-group command on GE-WAN interfaces if
MPLS is configured. You must remove all IP, MPLS, and other Layer 3
configuration commands before using the
channel-group command with GE-WAN interfaces.
 Note |
The GE-WAN interfaces on an OSM-2+4GE-WAN+ OSM behave slightly
differently than other interfaces if you want to move the interface from one
group to another. To move most other interfaces, you can enter the
channel-group command again to delete the
interface from the old group and move it to the new group. For GE-WAN ports,
however, you must manually remove the interface from the group by entering the
no channel-group command before assigning it to a new
group.
|
 Caution |
Do not enable Layer 3 addresses on the physical EtherChannel
interfaces. Assigning bridge groups on the physical EtherChannel interfaces
causes loops in your network.
|
For a complete list of guidelines, see the “Configuring EtherChannel”
section of the
Cisco 7600 Series Router Cisco IOS Software Configuration Guide.
Fast EtherChannel
Before you assign a Fast Ethernet interface to a Fast EtherChannel
group, you must first create a port-channel interface. To create a port-channel
interface, use the
interface port-channel global configuration
command.
If the Fast Ethernet interface has an IP address assigned, you must
disable it before adding the Fast Ethernet interface to the Fast EtherChannel.
To disable an existing IP address on the Fast Ethernet interface, use the
no ip addresscommand in interface configuration mode.
The Fast EtherChannel feature allows multiple Fast Ethernet
point-to-point links to be bundled into one logical link to provide
bidirectional bandwidth of up to 800 Mbps. Fast EtherChannel can be configured
between Cisco 7500 series routers and Cisco 7000 series routers with the 7000
Series Route Switch Processor (RSP7000) and 7000 Series Chassis Interface
(RSP7000CI) or between a Cisco 7500 series router or a Cisco 7000 series router
with the RSP7000 and RSP700CI and a Cisco Catalyst 5000 switch.
A maximum of four Fast Ethernet interfaces can be added to a Fast
EtherChannel group.
 Caution |
The port-channel interface is the routed interface. Do not enable
Layer 3 addresses on the physical Fast Ethernet interfaces. Do not assign
bridge groups on the physical Fast Ethernet interfaces because it creates
loops. Also, you must disable spanning tree.
|
To display information about the Fast EtherChannel, use the
show interfaces port-channelEXEC command.
For more guidelines see the “Configuring EtherChannel” section of the
Cisco 7600 Series Router Cisco IOS Software Configuration Guide
and the “Configuring EtherChannel” section of the
Catalyst 6500 Series Switch Cisco IOS Software Configuration
Guide