if i do not assign "switchport access vlan 50", how I know that particular trunk port is for vlan 50?

Hi,

first you define this Cisco port as an uplink port to the 3Com Switch and put .1q encapsualation on it:

- switchport mode trunk

- switchport trunk encapsulation dot1q

Then you define the vlans which shall run over this port (not necessary when all vlans shall be allowed):

- switchport trunk allowed vlan add 1,2,10

or you say allow all vlans except...

- switchport trunk allowed vlan except 1,2,10

maybe you should define speed and duplex on both port statically - not auto!

Greetz from Germany ;)

Like described in Alexander's post, by default, all VLAN's will allow to traverse a trunk port. If you want to limit/control a specific VLAN's to traverse over the trunk port, you can configure with the command:

switchport trunk allowed vlan x,y,z

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_25_see/configuration/guide/swvlan.html#wp1150302

HTH,

jerry

Just to clarify, as others have said you need to remove the "switchport access vlan 50" part of your config.

However the 2960 only supports 802.1q encapsulation so the command "switchport trunk encapsulation dot1q" is not necessary and won't be available.

Jon