Etherchannel Notes

Etherchannel

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used to aggregate bandwidth of physical links

-same logic as PPP multilink

Consists of two parts

-port-channel interface

 ie logical interface representing the link bundle

-members interfaces

 physical links part of a link bundle

Channel can be any type of interface

 ie layer 2 access, trunk, tunnel or l3 routed.

Etherchannel Negotiation

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channel-group [number] mode [mode]

Mode determines how negotiation occurs

- ON

 No negotiation

- Desirable & Auto (used in PAgP)

 Initiate of listen for PAgp

- Active and Passive (used in LACP)

  In active state  send LACP and in passive state listen for LACP

PAgp vs LACP is like ISL vs 802.1q also LACP is defined in 802.3ad

Ether channel Mode compatibility

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On - On

Desirable - Desirable

Desirable - Auto

Active - Active

Active - Passive

Ether Channel Load Balancing

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Load balancing between member interface based on..

-source mac

-dest mac

-source ip

-dst ip

-combinations of four

Modified with..

- port-channel load-balance

Layer 3 EtherChannel

=====================

Issue the no switchport command on members interface first

- order of operations issues

Ip address and other logical options go on the Port-channel interface

Ether Channel

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show etherchannel summary

L2 : show spanning-tree

L3 : show ip route