VPN ID and Route Target

Answered Question
Aug 22nd, 2007

Hello,

I am little bit confused about the VPNID and Route Target... it looks like both are doing the same function so when we need VPNID and when we need RT?

regards

Devang

I have this problem too.
0 votes
Correct Answer by swaroop.potdar about 9 years 3 months ago

Devang,

You got it right, VPNID has nothing to do with routes exchange. all VRF;s belonging to a VPN should be assigned the same VPNID. So the VPNID is essentially used to isolate data and control traffic virtually.

HTH-Cheers,

Swaroop

Mohammed, its ok, happens all the time :-).

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4.8 (4 ratings)
Loading.
swaroop.potdar Wed, 08/22/2007 - 11:54

Although the behaviour is the same, thats is of assigning membership. But the usage and assignment is very different.

RT can be used to assign membership by exchanging routes between VRF's with matching RT's, the VPNID being globally unique

cannot do route exchange, but can help assign membership of a incoming control or data packet which has the VPNID to a particular VPN, although this cannot be done with RT's.

The Cisco implementation of VPNID is MPLS VPNID, which is using this feature integrated into MPLS VRF's to assign incoming remote users to appropriate MPLS VPN's. So originally this feature per RFC 2685 is independent of IP or MPLS, but just provides a globally unique identifier for any type of usage as felt appropriate.

MPLS VPNID is one such usage for remote users. the RFC 2685 though short describes this aptly.

Just a wild though on possible future implementations of VPNID can be a consortium of many service providers providing seamless roaming support for VPN's.

Wherever you connect, just based on the incoming VPNID details you would be mapped across to your VPN.

Although you may search for VPNID and get many documents, just providing some links to start with.

Reference:

RFC 2685:

http://faqs.org/rfcs/rfc2685.html

MPLS VPNID:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1612/products_feature_guide09186a00800e9555.html

HTH-Cheers,

Swaroop

devang_etcom Thu, 08/23/2007 - 08:10

Swaroop,

It means VPN id is just identify the vpn connection between vrf... there is nothing to do with import and export of routes...right!!!

VPNID configuration under VRF will just inform that update will be carried with that perticular vpn... so both the end vrf will have same vpn id...righ!!! as well as multiple vrf can use the same VPNID too... is that correct?

so i think the use of VPNID is to isolate the updates virtualy that is right!!!

regards

Devang

Correct Answer
swaroop.potdar Thu, 08/23/2007 - 09:54

Devang,

You got it right, VPNID has nothing to do with routes exchange. all VRF;s belonging to a VPN should be assigned the same VPNID. So the VPNID is essentially used to isolate data and control traffic virtually.

HTH-Cheers,

Swaroop

Mohammed, its ok, happens all the time :-).

mohammedmahmoud Wed, 08/22/2007 - 11:58

Hi Devang,

Actually there is no relation, you can identify VPNs by a VPN ID, as described in RFC 2685. This implementation of the VPN ID feature is used for identifying a VPN. The VPN ID feature is not used to control the distribution of routing information or to associate IP addresses with VPN ID numbers in the MP-BGP VPNv4 routing updates.

Configuration of a VPN ID for a VPN is optional. You can still use a VPN name to identify configured VPNs in the router. The VPN name is not affected by the VPN ID configuration. These are two independent mechanisms to identify VPNs.

You can use a VPN name (a unique ASCII string) to reference a specific VPN configured in the router. Alternately, you can use a VPN ID to identify a particular VPN in the router. The VPN ID follows a standard specification (RFC 2685), thus the VPN ID is similar to the VRF name.

[edit] Sorry Swaroop didn't see your reply.

HTH,

Mohammed Mahmoud.

Actions

This Discussion