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VLAN issue when connecting 2 JG898A units

Wads
Occasional Advisor

VLAN issue when connecting 2 JG898A units

I have a problem with traffic flow between 2 x JG898A units connected together in the following configuration

The 2 switches are connected together via VLAN1 and a fibre cable using the SFP+ ports and the required GBIC’s and this works as expected however a second VLAN is required between the 2 switches for a backup system to isolate traffic from VLAN1.

Ports 40 of 1 switch and port 33 of the second switch have been configured as access ports for VLAN2, an IP address for the backup subnet has been configured on switch 1 for VLAN2, and additional ports on the second switch have been added to VLAN2 to connect the backup equipment.

Traffic flow works as expected between VLAN1 and VLAN2 at all times the issue I have is I cannot get traffic to flow between the 2 switches via VLAN1 at all even though the ports appear to be configured correctly.

The 2 switches need to be connected via VLAN1 to maintain standard network access for users located in the same building as the backup equipment

Currently the same configuration using a Procuve 2900 as the main switch and a Procurve 1810 is working just fine.

13 REPLIES
AlexisKoch
Advisor

Re: VLAN issue when connecting 2 JG898A units

Hello,

 

I don't understand your problem... "Traffic flow works as expected between VLAN1 and VLAN2 ... I cannot get traffic to flow ... via VLAN1 ".

 

Do you have IMC? You can see the vlan topology in "vlan management" -> "vlan topology".

 

Can you give us the conf of the ports? Maybe a access/trunk/hybrid problem with different default vlan.

Wads
Occasional Advisor

Re: VLAN issue when connecting 2 JG898A units

Hi Alexis,

                Please bear with me as I’m relatively new to the 5700 model and Comware CLI and I don’t have HP’s IMC either.

 

I’ve attached the current configurations for the 2 switches.

 

Please think of the switches as both having 2 separate broadcast domains configured, the default VLAN1 and the newly configured VLAN2. When a cable is connected between the 2 switches using any of the VLAN1 ports traffic will not flow over VLAN1 between the 2 switches whilst a cable is connected between the 2 switches using the VLAN 2 ports for some reason. When I disconnect the VLAN2 cable between the 2 switches traffic on VLAN1 will begin to flow. Traffic over VLAN2 from the CarstenCt switch to VLAN2 and VLAN1 on the SrvRm switch flows regardless of whether a cable using the VLAN1 ports is connected between them or not.

 

I’m sure I’m missing something fundamental here but for the life of me can’t see and happy to draw a diagram if that will help.

 

VoIP-Buddy
Trusted Contributor

Re: VLAN issue when connecting 2 JG898A units

In order to get the second VLAN across to the other switch the fiber connection needs to be set as a trunk port and the VLANs have to be permitted to go across the link.  The VLANs with run in "parallel" across the fiber link.

 

That should give you the connectivity that you need.

 

David

Wads
Occasional Advisor

Re: VLAN issue when connecting 2 JG898A units

Hi David,

                   I could do that but we have 2 fibre runs between the 2 switches and want to separate backup traffic from production traffic.

 

The thing that is frustrating me is the existing Procurve 2910 in the server room and the Procurve 1810 at Carsten Ct have been running the same configuration happily for years.

 

Graham

Vince-Whirlwind
Honored Contributor

Re: VLAN issue when connecting 2 JG898A units

When you have the two links patched in - what is your interface status on the four relevant interfaces?

Vince-Whirlwind
Honored Contributor

Re: VLAN issue when connecting 2 JG898A units

And compare what you see with what's (not) on your two Procurve switches.

Wads
Occasional Advisor

Re: VLAN issue when connecting 2 JG898A units

All 4 are up and connected at 10GB

Wads
Occasional Advisor

Re: VLAN issue when connecting 2 JG898A units

As are the inerface on the Procurve switches.

 

This is why its driving me nuts, I can't see an obvious reason why I having a porblem.  :)

sdide
Respected Contributor

Re: VLAN issue when connecting 2 JG898A units

Hi Wads,

 

What link transports vlan 1 between the 2 switches?

 

btw, if you want to have diffrent vlans running on each thier seperate link and want to run STP, you need to run pvst, or configure mstp (accordingly)

 

] stp mode pvst

 

otherwise all but one link - and therefore all but one vlan will be blocked.

 

Regards

Søren Dideriksen, Network Administrator
Region Midtjylland
Vince-Whirlwind
Honored Contributor

Re: VLAN issue when connecting 2 JG898A units

Seriously, "display interface"...

Wads
Occasional Advisor

Re: VLAN issue when connecting 2 JG898A units

Hi Soren,

                 Apologies for the delay in replying as long weekend with a public holiday in my region meant I haven’t take another look until now.

 

In response to your first question it doesn’t matter what ports I use to interconnect VLAN1 between the 2 switches, whether its UTP ports or fibre ports the result is the same.

 

I have very little experience with STP so please bear with me.

 

What you are suggesting is that even though the 2 VLAN’s are logically isolated I still need to worry about STP or MSTP?

 

Regards

Graham

sdide
Respected Contributor

Re: VLAN issue when connecting 2 JG898A units

Hi Wads,

 

what I was saying was :

 

If you have several trunks between switches, and you run only one (global in a vlan-sense ) stp instance. You better have all your vlans allowed on all trunks, otherwise you risk that stp blocks some links that are crucial to a specific vlan.

 

If you don't want to worry about stp blocking trunks with several vlans, you could run the "per vlan spanning tree"-protocal. pvst. This will make a topology for EACH vlan. 

 

What i am saying now is:

 

please post:  "display  interface <relevant-interface>"

please post : "display stp"

please post : "display lldp ne list"

 

relevant interfaces could be those interconnecting the two switches.

 

Regards.

Søren Dideriksen, Network Administrator
Region Midtjylland
Wads
Occasional Advisor

Re: VLAN issue when connecting 2 JG898A units

Hi Soren,

                   Ok now I have a handle on the issue can resolve it through configuring pvst as required.

 

Really appreaciate you help and patience with this.

 

Regards

Graham