DHCP Relay in MPLS VPN Backbone with 6509 Switches

[Samer Labaky]

Hi Experts,

i am configuring an MPLS VPN configuration with 6509 Switches, i need to install a DHCP server for the users located in different VRFs.

i need to configure the DHCP server in a way to provide overlapping IP addresses for different VRFs.

As far as i know, in order for this to happen, we have to let the relay agent, the 6509 router in my case to add VPN-related suboptions into the relay agent information option:

- VPN identifier

- Subnet selection

- Server identifier override

like this the DHCP server will be able to identify the VPN in which the client resides and send the needed IP address…

This can be done by configuring the "ip dhcp relay information option vpn" command, but unfortunately this is not supported on the 6500 platform.

Do you have any idea what can be done in this case, is there any alternative solution to be done in order to allow overlapping IP address assignment via DHCP in an MPLS environment having only 6500s as PE Routers.

Your quick reply is highly appreciated.

Best Regards,

Samer Labaky

CCIE # 24675

[Samer Labaky]

Hi Experts,

i forgot to mention that i was reading an interesting document on Cisco website "network virtualization design guide",  and they clearly mentioned the below:

"""VRF-awareness for DHCP-relay functionality is currently not supported on any Catalyst platform, but it is required only for supporting overlapping IP addresses"""

So i would like to ask you if you have any workaround to be done in such deployments

Thank you in advance

Samer Labaky

CCIE # 24675

[Samer Labaky]

Hi Experts,

any news ?