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Lab 10Hands-on Lab

Implement & Tune EtherChannel

Link Aggregation

Goal

Build an EtherChannel between switches, then tune its load-balancing method and verify how traffic is distributed.

EtherChannelLACPLoad BalancingHashTrunk
1

Implement & Tune EtherChannel

R1#
! S1 (toward S2/S3 per topology)
interface range g0/1-2
 channel-group 1 mode active

! Other switch
interface range g0/1-2
 channel-group 1 mode passive

interface port-channel 1
 switchport mode trunk
 switchport trunk allowed vlan 10,20
2

Build an EtherChannel between switches, then tune its load-balancing method and verify how traffic is distributed.

R1#
show etherchannel summary
show etherchannel load-balance
show etherchannel port-channel

Link Aggregation

3

Create the EtherChannel (LACP)

Verify Before Tuning

R1#
port-channel load-balance src-dst-mac        ! good for IP devices on VLANs
port-channel load-balance src-dst-ip         ! balances across different hosts/IPs
port-channel load-balance src-mac
port-channel load-balance dst-ip

show etherchannel load-balance
4

Note the default load-balance method (e.g., src-dst-mac / dst-ip).

Tune Load Balancing (the "tune" part)

R1#
show interface g0/1 counters
show interface g0/2 counters
5

Choose a method that spreads the lab's test traffic better, apply the required method, then verify.

R1#
interface g0/1
 shutdown

Demonstrate the Distribution (if required)

6

From a PC, ping/stream to another PC across the channel while running show interface g0/1 counters and g0/2 counters; observe whether traffic splits across both physical links based on the hash. Repeat with a different method to see the difference. Some lab versions ask for a policy-map or platform etherchannel load-balance — use whatever the lab's verification commands request.

R1#
show etherchannel summary
show etherchannel load-balance
show etherchannel port-channel
show interfaces trunk
show running-config | include load-balance

Common Pitfalls