Tune & Optimize EtherChannel Operations
From Cisco's Networking Academy ENCOR Lab Guide
5.1.4 Lab - Tune & Optimize EtherChannel Operations
Part 1: Build the Network and Configure Basic Device Settings
Open Standard: Link Aggregation Control Protocol (LACP), maintains EtherChannel Bundles. LACP supports 8 active members and 8 standby members in each bundle. Minimum and Maximum # of links and timing of LACP packets may be configured.
Part 2: Tune LACP based EtherChannel
EtherChannel bundles using LACP as its negotiation protocol can have up to 16 assigned members, with 8 active ports passing traffic and 8 ports on standby.
LACP bundle switched negotiate a master/slave relationship and the designated master switch makes the decision on which members are active and which are in "hot standby" mode when the number of members in the bundle exceeds 8.
Minimum and Maximum # of ports in a port channel can be configured.
DSW1 & DSW2 EtherChannel Bundle w/ LACP as negotiation protocol with 2 links and a max. of 3. Manually set a master. Enable LACP fast packets and reduce time out period from 30 to 1 second(s).
Configure Master Switch Criteria
Each LACP switch has a system-ID value. SW with lowest system-ID is the master. System-ID = system priority (32768 by default + base MAC Address). The priority value for LACP doesn't scale in multiples of 4096. (Unlike Spanning Tree Protocol).
Use "show lacp sys-id" (display sys-id) on DSW1-DSW2.
Modify LACP sys-ID in DSW2 (lacp system-priority 1)
Configure bundle size and member preferences
Interfaces are selected to be included in the active bundle based on their interface id. Lower numbered interfaces are added to the bundle until maximum size. Remaining interfaces are put in hot standby mode
Shutdown interfaces between DSW1 & DSW2
Configure links connecting DSW1 & DSW2 into a LACP EtherChannel bundle. Use Channel Group number 12 and the Active Mode. Configure interfaces for LACP fast
Configure port-channel 12 on DSW1 & DSW2 w/ a LACP minimum bundle size of 2 interfaces, maximum bundle size of 3 interfaces. Max value is only needed in master switch. Configuring it on both ends may help with troubleshooting. Verify that the EtherChannel bundle has formed and note the ports that are included versus the port that is in hot standby mode. (show EtherChannel summary).
Part 3: Explore EtherChannel Load Balancing
Load Balancing method in EtherChannel is a global Settings on the switch. All Ether-channels in a SW will use the method selected. Load Balancing methods used at either end of the EtherChannel Bundle do not have to match.
By default Cisco Catalyst 3650 and 2960 SW load-balance using MAC Address.
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