Re: Distribution of VPN routing info. to P routers

[Muneyoshi Suzuki <suzuki.muneyoshi at lab.ntt.co.jp>]

Vishal,

> About the dedicated router approach -- as I understand it,
> in it there is a dedicated physical router per customer,
> which then interfaces with a provider router (say via BGP).
> (The dedicated physical routers per customer, together with
> the corresponding provider router to which they connect, are
> equivalent to a "PE" router.) 
> The provider network is not assumed to be MPLS-enabled,
> so all P/PE routers need to be BGP peers, and thus learn
> of all customer routes in all VPNs.

The above approach seems to me something like VR approach. However,
I'm not sure whether it can support VPN services.

It is essential for VPN technologies to identify customer traffic
inside provider network. This is because, customers may use duplicated
IP address spaces such as private address and illegal address.
Therefore, tunneling technologies such as MPLS, GRE, IP-in-IP, IPsec,
that assign an additional identifier to customer packet,
is used to distinguish customers traffic. Needless to say, ATM VPI/VCI,
FR DLCI could also be used for the identifier.

So, I think it is not practical to provide VPN services with combined 
IP routers which do not support tunneling protocols.

Thanks,


Muneyoshi Suzuki
Nippon Telegraph and Telephone Corp.