STP and VLAN questions

[jlajuarez]

1. Is it possible to configure 2 trunk ports in a switch? If it is, are there any negative effects to the network?

2. So in order for me to implement STP on vlan configured switches, i have to have at least 2 trunks on a switch?

Kinda confused here... even my questions are confusing. :|

[cadet alain]

Hi,

trunking and STP are 2 different things:

trunking in Cisco lingo is having a link which can carry multiple vlans and to distinguish from which vlan the frames are coming you tag them with a vlan id( 802.1q) or you encapsulate the frame with a new header containing vlan id(ISL).

spanning-tree is a technology used to combat layer 2 loops as there is no such mechanism as TTL built in the frames.

Regards.

Alain.

[ranraju · Accepted solution]

To answer your questions...

1. Is it possible to configure 2 trunk ports in a switch? If it is, are there any negative effects to the network?

Yes you can configure 2 trunk ports on the switch, infact you can configure any number of trunk ports in the switch, there is no limitation specified for that. And if the trunk ports are configured correctly, without any native vlan mismatch on it, and as long as you have allowed correct number of vlans on the trunk, it will not have any negative effects in the network.

2. So in order for me to implement STP on vlan configured switches, i have to have at least 2 trunks on a switch?

Again, there is no specific requirement as such for you to have a minimum number of trunks to implement spanning tree. Basically, the purpose of a trunk port is to send more than one vlan data over it, and usually another switch is connnected to the other end of the trunk link, which should also be configured as a trunk.

Hope this answers your queries.

Regards,

ranraju