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Link Aggregation on Catalyst 3750


Our company purchased Cisco Catalyst 3750 WS-C3750G-24TS-S switch in order to test our device functionality - Link Aggregation Feature. I'd like to discuss the following issues:

a. Is it possible to change LACP protocol's timeout (long to short)?

b. As we saw, if one of aggregated links

falls down Catalyst removes it from the bundle and do not restores it in case of

link's connectivity restoration. Is it possible to change this behavior?

Thanks in advance,



Re: Link Aggregation on Catalyst 3750

What are you channeling to? Another switch or a server, etc? I don't believe you can change the LACP timeout, but you need to be sure that the other device actually supports standardized LACP, not PaGP or basic Etherchannel (like older Nortel, 3Com, HP, Extreme). Also, what are you running over the channel, a dot1q trunk, L3 channel with IP, etc?

Community Member

Re: Link Aggregation on Catalyst 3750


Two optical links of our device are connected to Catalyst switch - this is actually 2Giga aggregated channel. Our device supports standardized LACP. This is a Catalyst configuration:

Switch(config)#interface range gigabitEthernet 1/0/25 -26

Switch(config-if-range)#channel-protocol lacp

Switch(config-if-range)#channel-group 1 mode active

Creating a port-channel interface Port-channel 1

Our device and Catalyst are in LACP synchronization, but, as I mentioned before, in case of link failure Catalyst removes this physical link from LAG bundle and do not restores it after links is UP again.

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