The MPLS-OPS Archive

["Bala Subrahmanyam Venkata" <bsubrahm@doradosoftware.com>]

Mark-

Thanx for the reply. See my comments inline:

> On a PE router, there is one VRF per connectivity requirement.
> To illustrate this, suppose the PE router in question is connected to the
> following:
>
> 1. A site in VPN A (which only requires intra-VPN connectivity)
> 2. Two sites in VPN B (both requiring only intra-VPN connectivity)
> 3. A site which requires connectivity to both VPN A and VPN B
>
> In the above example there are a total of four sites, but only three
> connectivity requrements, and therefore you would have THREE VRFs.


So in your example above, say 1 refers to Site P, 2 refers to Sites Q & R
and 3 refers to Site S, do we still have three VRF's ? Can you tell me
what the contents of the VRF's be (in addition to routes from other CE
Routers
in VPNs A and B which are directly connecting to some PE's to which the
PE in question is peering )


>
> As to route lookup within a VRF, it is the same as would be true for a
> regular routing table - based on longest match.
> Import of routes into VRFs is very important here. Routes are
> imported into
> VRFs based upon Route Targets (RT).
> Routes are exported from VRFs with certain RTs (RTs are BGP extended
> communities, and take the form <type><AS number><32bitvalue>, or
> <type><IP
> address><16bitvalue>).
> To provide communication to other sites, you simply import routes
> with the
> appropraite RTs to the site VRF.
> This methodology allows the provisioning of very complex topologies
> (connectivity models), eg. simple VPNs, overlapping VPNs, hub-and-spoke
> VPNs, etc.
>
>

TIA

bala


-------
The MPLS-OPS Mailing List
Subscribe/Unsubscribe:  http://www.mplsrc.com/mplsops.shtml
Archive: http://www.mplsrc.com/mpls-ops_archive.shtml