Trunking Cisco to 3Com

[Lupin]

Is it possible to set up a trunk between a Cisco 6509 and a 3Com switch ?

I've created a trunk on the 3Com and an ether-channel on the Cisco which seems to work with pings etc. But when the users start to log on, I get lots of collisions and the link becomes unusable.

Help ??

 

[DanielBowen]

Etherchannel reuqires ISL to function, ISL is Cisco propriatary and therefore the 3com switch wouldn't negotiate a link. Try setting the trunk link to 802.1q and see what happens !

Dan,

 

[wybnormal]

Trunk in Ciso does not mean the same thing as 3Com. 802.1Q is THE only option for the connection. VLANs will NOT transfer directly.. there was some issue about it and I do not recall exactly what is was.. I may have some docs here about it but I need to dig around a bit.

MikeS Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[Lupin]

Sorry, my mistake.

When I say trunk, I actually mean a bundled channel of four ports that I'm trying to connect the Cisco 6509 and the Corebuilder 3500 together with.

Any suggestions ??

 

[Gandorf]

That won't work at all. A 3Com 3500 switch is a Layer 3 switch, and it thinks each port is an interface like a router does. Best bet is to cut your losses and use the Routing engine of the 6509. In testing our 6509 with a SupII we killed a 3500 with the amount of packets Cisco could process even at 100mb uplinks, 3Com would drop packets under moderate load.

 

[wybnormal]

You can connect them but it will require you to be creative. You need to setup 4 vlans on the 6500... a port to a vlan.. you need the extra ports on the 3500.. you need to use a combo of access lists and policy routing on the cisco to balance the packets to the 3500.

But.. wait.. it gets better ;-) In order to pass routing info, be prepared to use OSPF between the two router modules so each can learn what the other knows.

It's messy.. a pain in the ass and generally a bad idea but you could do it if you really wanted to.

My vote is with Gandorf and dump the 3500. If I remember right it's EOL recently? I know we has 3com out 4 times to get ours up and running, they finally gave up and gaves us the 3500 for free. Seems it didnt like IPX very much. We pulled it and used it later when 3com pulled out of the enterprise as trading material with Cisco.

MikeS
Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[Lupin]

I'll try and find another way round it.

Thanks anyway Gents.