Here is the description right out of the horse's (cisco's) mouth:
EtherChannel provides fault-tolerant high-speed links between switches, routers, and servers. You can use it to increase the bandwidth between the wiring closets and the data center, and you can deploy it anywhere in the network where bottlenecks are likely to occur. EtherChannel provides automatic recovery for the loss of a link by redistributing the load across the remaining links. If a link fails, EtherChannel redirects traffic from the failed link to the remaining links in the channel without intervention.
Don't worry about the VTP settings, they don't apply to etherchannels. Etherchannels are a link aggregation, that is they allow you to uplink from pairs of interfaces, providing load balancing and greater bandwidth. Normally, if you have multiple connections between switches, spanning tree will block all but one. There is the IEEE standard LACP (802.3ad) and Cisco's proprietary PAgP. There are slight differences, but keep in mind that both switches need to run the same type of etherchannel. So if it's Cisco to a different vendor, use LACP, if it's Cisco to Cisco, use whatever you want (as long as they match).
That's not to say don't check your VTP config, if your switches aren't working, that's something to look at. If it's just two switches, consider using transparent mode. It's simpler than setting up VTP servers/clients.
Re: vlan and trunking configuration....newbie need help
13 years 9 months ago #9679
Etherchannel really is good. As jwj points out, normally if you have multiple links between devices then spanning tree will block all of them except one. If you combine the links into an etherchannel instead then you can have them all working a the same time. Why waste all that lovely bandwidth? And you still get resilience because if one of the component links fails the others carry on