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VLAN across 2 switches

Mike Zalamea
Occasional Contributor

VLAN across 2 switches

Hi all,

Let me preface this message by saying that I'm new to networking. I've done a lot of reading in these forums and the manuals regarding VLANs, but for whatever reason, I'm still unable to get VLAN's working.

Here's what I want to do:
We have to 2 HP switches, 2848 and 3400. I want to VLAN our SAN, Servers and End users. I've created a Corp VLAN(vlan 1, 192.168.150.x), SAN VLAN (vlan 100, and Server VLAN (vlan 200, 192.168.300.1) on both switches. IP routing is enabled.

I understand how the untagging/tagging works. all ports on each vlan are untagged, with a port tagged in a vlan only if it will communicate with another vlan, correct?

My questions are:
1) How do I extend the VLAN's between the switches? Can i do this for disaster recovery purposes in case 1 switch goes down? I have NIC teaming enabled on each server and want to plug in 1 nic on each switch.

2) Do I need IP routing enabled in order for the VLAN's to talk? I would want the Corp VLAN to talk to the Server VLAN and the SAN VLAN to talk to the Server VLAN.

3) What should the default gateway's be for each of the VLAN's?

4) Should I implement trunking? If so, can I do this using 2 mini GBIC's? LACP?

5) Should I use Spanning Tree? If so, what needs to be configured on each switch?

6) Any other options/configs I should look at?

Any suggestions/answers/best practices regarding my setup would be greatly appreciated. I will definitely give out points for those who respond.

Thanks for your time and let me know if you need configs/diagrams!
Nameesh NR

Re: VLAN across 2 switches

Hi Mike,

Here are the answers to some of your questions-

(1) Initially configure 3 VLANs on one of the
switches, preferably 3400. Assign IPs to
them as 150.1, 200.1 and 300.1.
Enable IP routing on the switch.
Enable "ip proxy-arp"

Configure similar VLANs on 2848 dvc and
assign IPs as 150.2, 200.2 and 300.2.
Disable IP routing.
Set IP default gateway on the 2848 dvc
as 150.1 (default VLAN 1)

Refer the following thread to get more
info on accessing across VLANs.


(2) Enable IP routing on 1 and disable on
the other.

(3) Refer (1) to get info on this as well.

(4) You can implement trunking on the need
basis. If you think that the data being transferred across switches is large and there is possibility of packet-drop. Then
you should be enabling trunking.
Which can help in transferring more data across switch. Trunking also does load-balancing.

(5) Spanning tree is not needed. It is generally needed in scenarios when
there are redundant links across switches causing a network look.
Enabling STP which will block the redundant link.
Another way would be enable meshing and have a fully connected domain.
Refer 34xx switch manual which you can get from the hpprocurve.com site for 34xx dvc.

If you can share the config/diagrams, I could give more ideas.

Dont forget to assign points :)
Nothing is too small to know, and nothing is too big to attempt.
Mike Zalamea
Occasional Contributor

Re: VLAN across 2 switches

Thanks for the response. I will try and make the changes this weekend and give you points accordingly.
Trusted Contributor

Re: VLAN across 2 switches

Don't listen to Nameesh: he's over the edge, stoned. Matt Hobbs could help you, if he sees this thread.