Understanding Port Channel Interfaces; Understanding Load Balancing; Etherchannel Feature Configuration Guidelines And Restrictions - Cisco 7604 Configuration Manual

Chapter 12 Configuring EtherChannels

Understanding Port Channel Interfaces

Each EtherChannel has a numbered port channel interface. With Release 12.2(18)SXE and later releases,
you can configure a maximum of 128 port-channel interfaces, numbered from 1 to 256. With releases
earlier than Release 12.2(18)SXE, you can configure a maximum of 64 port-channel interfaces,
numbered from 1 to 256.
The configuration that you apply to the port channel interface affects all LAN ports assigned to the port
channel interface.
After you configure an EtherChannel, the configuration that you apply to the port channel interface
affects the EtherChannel; the configuration that you apply to the LAN ports affects only the LAN port
where you apply the configuration. To change the parameters of all ports in an EtherChannel, apply the
configuration commands to the port channel interface, for example, Spanning Tree Protocol (STP)
commands or commands to configure a Layer 2 EtherChannel as a trunk.

Understanding Load Balancing

An EtherChannel balances the traffic load across the links in an EtherChannel by reducing part of the
binary pattern formed from the addresses in the frame to a numerical value that selects one of the links
in the channel.
EtherChannel load balancing can use MAC addresses or IP addresses. EtherChannel load balancing can
also use Layer 4 port numbers. EtherChannel load balancing can use either source or destination or both
source and destination addresses or ports. The selected mode applies to all EtherChannels configured on
the router. EtherChannel load balancing can use MPLS Layer 2 information.
Use the option that provides the balance criteria with the greatest variety in your configuration. For
example, if the traffic on an EtherChannel is going only to a single MAC address and you use the
destination MAC address as the basis of EtherChannel load balancing, the EtherChannel always chooses
the same link in the EtherChannel; using source addresses or IP addresses might result in better load
balancing.

EtherChannel Feature Configuration Guidelines and Restrictions

When EtherChannel interfaces are configured improperly, they are disabled automatically to avoid
network loops and other problems. To avoid configuration problems, observe these guidelines and
restrictions:
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OL-4266-08
The commands in this chapter can be used on all LAN ports in Cisco 7600 series routers, including
the ports on the supervisor engine and a redundant supervisor engine.
Release 12.2(17b)SXA and later releases provide support for more than 1 Gbps of traffic per
EtherChannel on the WS-X6548-GE-TX and WS-X6548V-GE-TX switching modules.
With Release 12.2(17a)SX and Release 12.2(17a)SX1, the WS-X6548-GE-TX and
WS-X6548V-GE-TX fabric-enabled switching modules do not support more than 1 Gbps of traffic
per EtherChannel.
The WS-X6148-GE-TX and WS-X6148V-GE-TX switching modules do not support more than
1 Gbps of traffic per EtherChannel.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
EtherChannel Feature Configuration Guidelines and Restrictions
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