Cisco Support Community
Community Member

Participation In Customer Routing.

Hello ,

I am sending one question which I believe was wrongly answered on Cisco forum.In forum the answer guessed is A but I think the answer is B.I am also giving some explaination.

Which one of the following is true?

A. MPLS and traditional peer-to-peer VPNs require the service provider to participate in

the customer routing.

B. MPLS and traditional peer-to-peer VPNs require that the customer routing is

transparent to the service provider.

C. MPLS VPNs require the use of link-state routing protocols, traditional peer-to-peer

VPN implementations require distance vector protocols.

D. MPLS VPNs are constructed using dynamic routing protocols; traditional peer-topeer

VPN implementations are constructed using static routes.

Consider the scenario. BGP/MPLS VPN is considered as provider provisioned VPN, where the edge

router takes part in provisioning VPN service.

example: VPN A has three sites, 1, 2, 3 connected to PE1, PE2, PE3


VPN A Customer routes from site 1 may or may not be directly reachable from

site 2, and site 3, depending on how they are provisioned by the Service

provider at PE. Infact customer has to depend on Provider for this


But the core routers in the provider network, is not aware of existence of

any VPN and does not process any route which belongs to customer network,

outside the provider's network.

That is what my interpretation is.

In that respect, the customer routing is transparent to the provider.

Request all of you to comment and come to the conclusion this is important question from Cisco 640-910 examination point of view also.

Regards ,

Ranjeet Badhe

Engineer (Access Networks)

Cisco Employee

Re: Participation In Customer Routing.

Agreed, the answer should be B not A.

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
CreatePlease to create content