Change Trunk mode - 3500XL?

[admin_2]

Don't see where I can change the VTP trunk mode on my 3500 switch. When I show int g 0/1 switchport, it tells me amoung other stuff that "Negotiation of Trunking: Disabled". Sure enough, it does not talk to the 4912 on the other end of the fiber set to Trunk Auto mode.

I would really like to set the 3500 to desirable mode and leave the 4912 in auto. As a fall back position, I set the 4912 to Trunk On mode which is successfully sending VTP info between the switches.

Any suggestions?

[Prashanth Krishnappa]

The 2900/3500XL series does not support desirable option for trunk

http://www.cisco.com/univercd/cc/td/doc/product/lan/c2900xl/29_35wc4/sc/swvlan.htm#xtocid42

If you have a 2950/3550, you can use desirable option

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12111ea1/3550scg/swvlan.htm#xtocid26

[lgijssel]

Try the following:

interface GigabitEthernet0/1

switchport trunk encapsulation dot1q OR isl, depending on your needs

switchport mode trunk

end

This should do it.

[milan.kulik]

And set trunk nonegotiate on your 4912 (if it's possible, I'm not a 4912 expert, this is the way it works on Cat4000s).

Regards,

Milan