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New Member

Are 3Com switches really better at link aggregation than Cisco switches?

If I configure two 3Com switches to run lacp on all ports, I can then connect any ports between the two switches and they will automatically determine which ports they share and turn those ports into a channel.

With Cisco switches it appears I have to go into the particular interfaces that will be connected to the same remote switch and enter the command:

channel-group channel-group-number mode {active|passive}

Is this correct or am I missing something?  Do Cisco switches really not support dynamically created channel groups?  Do I really have to tell the Cisco switch which interfaces to aggregate?  Is there no way to just enable lacp on all ports and let the switches figure out which ports they share?

Everyone's tags (2)

Are 3Com switches really better at link aggregation than Cisco s

I wouldn't say one is "better" than the other, just that they are configured differently.  An analogy would be saying that Mac or Windows is better than Linuxbecause of the amount of configuration one must complete on the latter.  Your post comes at an opportune time, as there is a post on Ivan Pepelnjak's blog about this very subject (though Cisco vs Juniper).

One could say 3com is "better" because there is less configuration involved.  But what about the other way around?  Say you configured (8) ports for aggregation, but for whatever reason you wanted two separate channels to each switch (one primary, one failover).  With the Cisco configuration, you easily accomplish this by changing the channel-group for the second set of interfaces.  Could you do this with the 3com switch, or does it force you to put all interfaces in the same group?

New Member

Re: Are 3Com switches really better at link aggregation than Cis

Yes, 3Com switches allow you to manually create groups.

Cisco switches appear to only use lacp to confirm you have connected things correctly by not grouping ports when the lacp information doesn't match the port groups you've configured.  I am just disappointed that Cisco switches do not appear to support the whole "automatic bundling of links" thing that lacp was designed for.

I apologize, I should have phrased the topic of this thread better.  I've been a bit of a Cisco bigot for a couple decades now, but there have been several incidents over the past month or so where Cisco has really let me down, and quite frankly cost me a lot of money and a fair bit of embarrassment.  This particular problem kinda pushed me over the edge and I'm afraid a little venting was done in this thread.

This was supposed to be a fairly simple design, and I just did a similar install for another customer last week with 3Com switches that went flawlessly.  In both cases I have stacked core switches with edge switches that have redundant connections to different core switches.  With the 3Com switches I just enabled lacp on all the core ports and the uplink ports of the edge switches and was done.  To do this same setup with Cisco switches it appears I will have to figure out where each edge switch is connected to, manually assign those ports to the same group, and make sure none of the uplinks ever get moved.

New Member

Re: Are 3Com switches really better at link aggregation than Cis

Perhaps I should note that this is a real question.  I find it hard to believe that Cisco switches are really this poorly designed.  I am seriously hoping that I am missing something.