topic Re: ProCurve 6120XG and variable length subnets in Switches, Hubs, and Modems

ProCurve 6120XG and variable length subnets

J.J. McDaniel — Mon, 03 May 2010 18:44:06 GMT

Hi.

I'm trying to use variable length subnets on a ProCurve 6120XG in a BladeSystem c7000.

We have divided a Class C network up in to 8 subnets, 255.255.255.224. If I go back to a plain Class C it works but does not when using variable length subnets.

Does the 6120XG support variable length subnets?

Thanks!

J.J.

Re: ProCurve 6120XG and variable length subnets

Lmm_1 — Mon, 03 May 2010 20:29:54 GMT

Are you assigning that IP address to an specific vlan or to the OOBM interface through the OA?

Re: ProCurve 6120XG and variable length subnets

rick jones — Mon, 03 May 2010 23:33:09 GMT

Given the 6120XG is a Layer-2 (Ethernet data-link) switch, apart from its management interface I don't see how it could care one way or another about how you subnetted the IP (Layer-3) address space used by the blades, all it is doing is switching Ethernet frames among the ports. Can you be a bit more specific about what you are trying to do and how?

Re: ProCurve 6120XG and variable length subnets

Pieter 't Hart — Tue, 04 May 2010 06:34:37 GMT

Question: Are you using all 8 subnets within the same network / (V)LAN? (this is called a multinet)
Or are this seperate networks/VLAN's?

In both cases the switch can forward data between ports in the same subnet. This is a layer-2 (switching) communication and has nothing to do with TCP/IP adresses (layer-3).

In the multinet situation you should allready have a router to forward traffic between VLAN's/subnets, else the subnets are isolated and cannot talk to eachother.
If not then the only way to make the switch reachable from all subnets is to give it an adress+subnetmask that matches all subnets.

The normal way to set things up it to create separate VLAN's for each subnet and configure a router to forward traffic between VLAN's/subnets.

As the previous poster mentioned this is a L2 switch you will need an additional router to forward traffic between subnets.

Re: ProCurve 6120XG and variable length subnets

J.J. McDaniel — Tue, 04 May 2010 12:36:17 GMT

Yes, I have a VLAN for each subnet. Here is my show config:

hostname "net1001.mckesson.com"
interface 23
disable
lacp Active
exit
interface 24
disable
lacp Active
exit
trunk 18-19 Trk1 Trunk
ip default-gateway 10.97.221.62
vlan 1
name "DEFAULT_VLAN"
untagged 1-17,20-24,Trk1
no ip address
exit
vlan 131
name "Citrix_Console"
ip address 10.97.221.61 255.255.255.224
tagged 1-17,20-24,Trk1
exit
vlan 132
name "Citrix_McKHost"
tagged 1-17
no ip address
exit
vlan 133
name "Citrix_D9H11"
tagged 1-17
no ip address
exit
vlan 134
name "Citrix_Customer"
tagged 1-17
no ip address
exit
vlan 135
name "Citrix_Open1"
tagged 1-17
no ip address
exit
vlan 136
name "Citrix_open2"
tagged 1-17
no ip address
exit
vlan 137
name "Citrix_AD_DC"
tagged 1-17
no ip address
exit
vlan 130
name "MGMT"
tagged 1-17,20-24,Trk1
no ip address
exit
vlan 220
name "VLAN220"
tagged 1-17,20-24,Trk1
no ip address
exit

Re: ProCurve 6120XG and variable length subnets

Pieter 't Hart — Wed, 05 May 2010 06:44:05 GMT

can you specify "If I go back to a plain Class C it works but does not when using variable length subnets"
what does work, what doesn't?
- can the switch ping this gateway and vice-versa?
- can the switch telnet to this gateway (vv)?

>>>
ip default-gateway 10.97.221.62
vlan 131
ip address 10.97.221.61 255.255.255.224
tagged 1-17,20-24,Trk1
<<<
looks basically allright

- what is this default gateway?
- on which port is it connected
(possibly somewhere at Trk1?)
- what's the subnet mask on this gateway?
- what's the vlan config of this gateway?

Re: ProCurve 6120XG and variable length subnets

J.J. McDaniel — Wed, 05 May 2010 11:03:30 GMT

Hey guys.

Thanks for the help. We found the issue.
My network guy forgot to put the Layer-2 switch in the route of the up stream switch.

IT (Layer 2) --> Brocade TurboIron 24x (Layer 3)--> ProCurve

once he put that switch from our IT deptartment in there the subnets were able to forward and resolve eachother.

We're working on getting a Layer 2 switch in the lab so we won't have to go so far up to resolve.

Thanks again!

J.J.

Re: ProCurve 6120XG and variable length subnets

J.J. McDaniel — Wed, 05 May 2010 11:04:09 GMT

closing thread.