configure 2 fiber links each different vlans

Question

configure 2 fiber links each different vlans

dashrender75 (TechnicalUser)

(OP)

11 Jan 10 10:44

I have a HP 2824 that currently has a single fiber connection to a set of 2650's (fiber to one, and copper 1GB between the two remote 2650's).  This link currently supports 4 VLANs.

I would like to install a second fiber link between the 2824 and the remote 2650 that does not have a fiber connection.  At the same time I want to create a 5th VLAN that I would use solely on this new fiber connection.

I have setup the 2824 and the second 2650 to both have VLAN (50) and the are both listing the associated fiber port as Untagged Ports.  I have NO tagged ports listed for this VLAN either.

When I connect my second fiber connection, I loose all connectivity on the primary fiber link.

Can you tell me why?  Thanks in advance!

unclerico (IS/IT--Management) · Answer 1 · 2010-01-11 11:05:05

spanning-tree

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- ColdFlame (vbscript forum)

dashrender75 (TechnicalUser) · Answer 2 · 2010-01-11 11:44:00

Doesn't seem likely since I have spanning tree turned off on all of these switches.

Also, for this VLAN, The only VLAN listed with an untagged port is port 50. I do have other VLANs listing port 50 as a Tagged Port though. Could that be part of the problem, even though Spanning Tree is turned off?

While I am waiting for an answer, I will remove port 50 from the other Tagged Ports and try again.

dashrender75 (TechnicalUser) · Answer 3 · 2010-01-11 13:32:36

OK... removing port 50 (fiber port on the 2824, and the second 2650) did infact resolve this issue.

Would having two paths, not trucked, to the main switch cause one or both of the lines to stop working even if Spanning Tree is turned off?

Thank.

ISPKing (ISP) · Answer 4 · 2010-01-15 19:12:50

Yes, If you do that you will most definetly kill your switches due to broadcast loops. Their procs will go though the roof, and stop passing traffic completly. The reason is the ttl on the broadcast never get decremented as they are only layer 2 forwarding so they circle indefinetly.

dashrender75 (TechnicalUser) · Answer 5 · 2010-01-18 15:39:28

ISPKing, thanks.

I guess I was kinda expecting 802.3ab or 802.1ax (link aggregation to kick in automatically.

I see now (at least on HP switches) that it is set to passive, and won't work unless at least one side of the LACP is set to active. Though (again, at least on HP's) this would not work for me since this link would only be valid for the default VLAN, and I really wanted this second connection to be primarily for VLAN 10.

Thanks for you help.

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configure 2 fiber links each different vlans