ISL Problem?

[DanielBowen]

Hi Everyone,

I am having problems with some ISL trunks that I ahve configured between a Catalyst 2900XL and a Catalyst 5500. I have two fiber uplinks on the 2900 connecting to two fiber uplinks on the 5500, now if these are configured as ISL trunks, I get multiple CRC errors on the both ports on the 2900 (the exact same number on each port). If I configure these as access links I do not get this.

Does anybody have any idea as to why this is occurring?

Thanks in advance,

Daniel,

 

[mavos]

Check channeling and make sure on the 5500 the ports are set to ISL nonnegotiate (? spelling).

See if that help.s

 

[DanielBowen]

I have the ports on the 5500 set to On, the same as the 2900XL ports. Would this cause a problem?

I assumed that both ends could be forced to trunk ISL and that would work?

Daniel,

 

[MelchiorKD]

also make sure the native vlan is the same on both ends