×

Warning message

  • Cisco Support Forums is in Read Only mode while the site is being migrated.
  • Cisco Support Forums is in Read Only mode while the site is being migrated.

Cisco vss - connect from access switch with no etherchannel

Answered Question
May 8th, 2012
User Badges:

Hi all

If I dual connect my access switch to my 6509s running vss, what will happen, will spanning tree still block one of the ports if I don't set up an etherchannel?

Cheers


Carl

Correct Answer by nikolasgeyer about 5 years 3 months ago

Assuming a basic topology where there is no VLAN trunking etc going on then yes, STP will block one of the links as you have created a layer 2 loop.


If the links were VLAN trunks and carrying all VLAN's on both links, the above blocking scenario would also apply.


If the links were VLAN trunks and only carrying a subset of VLANs on link #1 and another subet on link #2 (e.g. VLAN's 100 and 110 on link 1 and VLAN's 200 and 210 on link 2) then no blocking would occur as there would be no layer 2 loop.


That should cover off pretty much all the scenarios you could use

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Loading.
Correct Answer
nikolasgeyer Wed, 05/09/2012 - 00:00
User Badges:
  • Bronze, 100 points or more

Assuming a basic topology where there is no VLAN trunking etc going on then yes, STP will block one of the links as you have created a layer 2 loop.


If the links were VLAN trunks and carrying all VLAN's on both links, the above blocking scenario would also apply.


If the links were VLAN trunks and only carrying a subset of VLANs on link #1 and another subet on link #2 (e.g. VLAN's 100 and 110 on link 1 and VLAN's 200 and 210 on link 2) then no blocking would occur as there would be no layer 2 loop.


That should cover off pretty much all the scenarios you could use

Actions

This Discussion