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.

Upgrade Interconnect from 1G to 10G

Unanswered Question
Nov 21st, 2013
User Badges:

We have a pair of 6509 w/SUP720-3BXL switches running HSRP and are connected via trunk using the sup 1G interfaces.  We did not create a channel-group, just direct connected.  We're now starting to realize this interface is not enough bandwidth and want to leverage some of the 10G interfaces.

My thinking was to create a channel-group and put at least one 10G interface on each switch into the group, but how can I force the switches to use the 10G over the 1G?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4.3 (3 ratings)
glen.grant Thu, 11/21/2013 - 08:13
User Badges:
  • Purple, 4500 points or more

    You cannot put different speed interfaces into a channel group. All interfaces in a channel group must be the same speed. 

fmagoufis Thu, 11/21/2013 - 08:28
User Badges:

yes, I was going to create a new channel group for the 10G interfaces, my question is more about what path with the traffic take once the switches recognize another path between them?

Path A - Single 1G

Path B - Channel-Group 10G

Jon Marshall Thu, 11/21/2013 - 11:27
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

If you have two separate paths between the 6500s then STP will have to block one of them because you have created a L2 loop. So it should block the 1Gbps path because the cost of 1Gbps is 4 and the cost of 10Gbps is 2.

So it should take the 10Gbps link. Be aware that because STP has to block the existing 1Gbps path you will see a shot outage while it reconverges so you should scehdule an outage to do this.


Reza Sharifi Thu, 11/21/2013 - 19:14
User Badges:
  • Super Bronze, 10000 points or more
  • Cisco Designated VIP,

    2017 LAN

In addition to what Jon noted (hi Jon, welcome back) you also need to make sure your HSRP active is aliened with your root bridge.  So, if you are planning to add the10Gig portchannel, you want to add it to the forwarding link first before you bring up the portchannel on the blocking link, so your STP topology stays the same.


fmagoufis Fri, 11/22/2013 - 05:27
User Badges:

Thank you Jon.  I was planning on a 5 minute maintenance window.


This Discussion

Related Content