Route Sub-IP address on VLAN

[Steffen Frederiksen]

Hi

I have some Procurve 5406 Layer 3 switches as Core swtiches in my network.
I have a VLAN with the IP 10.31.45.1, that IP is default Gateway for the 10.31.45.1/24 network.
In the same VLAN I've connected a Cisco router with one interface, that interface has two sub-ip addresses 10.31.46.1 and 10.31.47.1. So right now the Cisco router is default gateway for the 10.31.46.0/24 and 10.31.46.47.0/24 network.

I would like to disconnect the cisco router, and add 10.31.46.1 and 10.31.47.1 as sub IP addresses to the vlan with the IP address 10.31.45.1, and I want the switch to route between those network.

I do not want to create three different VLANs, because the segment is just for easier administration, and not for security etc.

Is it possible to add sub-ip address to a VLAN interface on procurve 5406 and be able to route between those networks eventhrough they are on the same VLAN in the siwtch?

Regards, Steffen, Denmark.

[Jeff Carrell]

Yes, you can have multiple IP nets on a single VLAN. It is not "referred" to sub-interfaces in the HP ProVision config like in Cisco IOS, simply add another IP to the VLAN:

switch(config) vlan 1 ip addr 10.31.45.1/24
switch(config) vlan 1 ip addr 10.31.46.1/24
switch(config) vlan 1 ip addr 10.31.47.1/24

Then to route between those 3 networks, enable IP routing:

switch(config) ip routing

hth...Jeff

[Steffen Frederiksen]

Hi - thank you for the quick answer!

I've just been told that someone has tried before to simply just add the ip address to the vlan, but that it didnt work, and therefore he added the cisco router as gateway for the 10.31.46.1 and 10.31.47.1 /24 network.

Are you sure that I simply just add the IP address for those networks? Do you have any HP documentation or link that can confirm it?

Ip Routing must be enabled since the switch is allready routing for the 10.31.45.0/24 network...

[Jeff Carrell]

Ref this chapter, page 8-9:
http://cdn.procurve.com/training/Manuals/3500-5400-6200-6600-8200-MCG-Mar10-8-IPaddr.pdf

Works every time I've ever done it :-)

I forgot you already had ip routing enabled (opps).

hth...Jeff

[rick jones]

Are yu sure the Cisco no longer sits between the hosts of those additional subnets and your 5406?

If any of the systems on those subnets are running HP-UX, or if they are running Linux and you've installed the linkloop port, you can use a linkloop command directed at the MAC address of the 5406 to see if there is layer 2 connectivity between that system and the switch.