Etherchannel Feature Overview; Understanding How Etherchannels Are Configured - Cisco 7604 Configuration Manual

Understanding How EtherChannels Work

EtherChannel Feature Overview

An EtherChannel bundles individual Ethernet links into a single logical link that provides the aggregate
bandwidth of up to eight physical links.
With Release 12.2(18)SXE and later releases, a Cisco 7600 series router supports a maximum of
128 EtherChannels. With releases earlier than Release 12.2(18)SXE, a Cisco 7600 series router supports
a maximum of 64 EtherChannels.
You can form an EtherChannel with up to eight compatibly configured LAN ports on any module in a
Cisco 7600 series router. All LAN ports in each EtherChannel must be the same speed and must all be
configured as either Layer 2 or Layer 3 LAN ports.
The network device to which a Cisco 7600 series router is connected may impose its own limits on the
Note
number of ports in an EtherChannel.
If a segment within an EtherChannel fails, traffic previously carried over the failed link switches to the
remaining segments within the EtherChannel. When a failure occurs, the EtherChannel feature sends a
trap that identifies the router, the EtherChannel, and the failed link. Inbound broadcast and multicast
packets on one segment in an EtherChannel are blocked from returning on any other segment of the
EtherChannel.

Understanding How EtherChannels Are Configured

These sections describe how EtherChannels are configured:
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EtherChannel Configuration Overview
You can configure EtherChannels manually or you can use the Port Aggregation Control Protocol
(PAgP) or the Link Aggregation Control Protocol (LACP) to form EtherChannels. The EtherChannel
protocols allow ports with similar characteristics to form an EtherChannel through dynamic negotiation
with connected network devices. PAgP is a Cisco-proprietary protocol and LACP is defined in IEEE
802.3ad.
PAgP and LACP do not interoperate with each other. Ports configured to use PAgP cannot form
EtherChannels with ports configured to use LACP. Ports configured to use LACP cannot form
EtherChannels with ports configured to use PAgP. Neither interoperates with ports configured manually.
Table 12-1
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
12-2
EtherChannel Configuration Overview, page 12-2
Understanding Manual EtherChannel Configuration, page 12-3
Understanding PAgP EtherChannel Configuration, page 12-3
Understanding IEEE 802.3ad LACP EtherChannel Configuration, page 12-4
lists the user-configurable EtherChannel modes.
Chapter 12 Configuring EtherChannels
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