topic Re: trunk and vlans in Switches, Hubs, and Modems

trunk and vlans

martinwa — Thu, 13 May 2010 16:59:58 GMT

Hi,

I am configurating two procurve gigabit switches to be used with my hp lefthand san (iscsi).
Need the switches to be split in two vlanâ s vlan11 to iscsi and vlan3 to the management.
My central network connects to vlan3 to both switches. One cable to each. And this works.
Vlan11 needs to be â trunkedâ between the two switches with the use of four cables. This works as well.
From my central network I can â pingâ switch1 10.0.0.58 and switch2 10.0.0.59.
But if I connecting the four trunk/uplink ports. Connection to 10.0.0.59 drops. Vlan11 works well between switch1 and 2.

What is wrong?
Vlan3 should not have anything to do with the trunk and vlan11.
Se my two attached configurations.
Best regards
Martin

Re: trunk and vlans

briand99 — Thu, 13 May 2010 20:13:17 GMT

vlan 11
name "VLAN11"
untagged 1-12,15-16,21-24,Trk1

Trk1 needs to be tagged for trunk and not untagged.

Re: trunk and vlans

martinwa — Thu, 13 May 2010 20:25:59 GMT

Do you mean change the line to:
untagged 1-12,15-16,21-24

?

Re: trunk and vlans

martinwa — Thu, 13 May 2010 20:49:24 GMT

Do i need to do something else than the port configuration. Se attached file?

Re: trunk and vlans

Pieter 't Hart — Fri, 14 May 2010 12:55:31 GMT

>>>
From my central network I can ping switch1 10.0.0.58 and switch2 10.0.0.59.
But if I connecting the four trunk/uplink ports. Connection to 10.0.0.59 drops. Vlan11 works well between switch1 and 2.
<<<

this seems to means you've got both switches connected to the "central network" using some other ports?

then when connecting both switches together you got a spanning-tree "loop".

- the "uplink" that vlan3 previously passed is blocked by spanning-tree, because the four-port interconnect of the two switches gets preference (greater bandwith).
- but Trk1 is not configured to pass vlan3!
=> so you lose connectivity

==>> configure vlan3 over Trk1 also
vlan 3
tagged Trk1
exit
on both switches.

Re: trunk and vlans

martinwa — Fri, 14 May 2010 17:26:03 GMT

spanning-tree ohhh yes, that was it.

Thank you.

Re: trunk and vlans

KSimpson — Mon, 17 May 2010 19:07:04 GMT

Spanning-tree is a wonderful thing. Just imagine if it was turned off! 8|