INE R&S ATC008 - Layer 2 EtherChannel, EtherChannel Load Balancing, Layer 3 EtherChannel

EtherChannel

Used to aggregate bandwidth of physical links
– Same logic as PPP Multilink

• Consists of two parts
– Port-Channel interface

• Logical interface representing the link bundle
– Members interfaces

• Physical links part of a link bundle
• Channel can be any type of interface

– i.e. layer 2 access, trunk, tunnel, or layer 3 routed

EtherChannel Negotiation

• channel-group [number] mode [mode]

• Mode determines how negotiation occurs
– On
• No negotiation
– Desirable & Auto
• Initiate of listen for PAgP
– Active & Passive
• Initiate Active: send LACP
– Passive: listen for LACP

• PAgPvs. LACP
– Like ISL vs. 802.1q

EtherChannel Mode Compatibility

• On –On
• Desirable –Desirable
• Desirable –Auto
• Active –Active
• Active –Passive

EtherChannelLoad balancing

• Loadbalancing between member interface based on…
– Source MAC address
– DestinationMAC address
– Source IP Address
– Destination IP Address
– Combinations of the four

• Modified with…
– port-channel load-balance

Layer 3 EtherChannel

• Issue the no switchport command on member interfaces first
– Order of operations issues
• IP address and other logical options go on the Port-Channel interface

EtherChannel Verification

• show etherchannelsummary
• Layer 2
– show spanning-tree
• Layer 3
– show iproute