4-3 - CSC for Layer 3 MPLS VPNs

Question 1

What is carrier supporting carrier (CSC)?

Answer 1

enables on MPLS VPN-based service provider to allow other service providers to use a segment of its backbone network.

Question 2

backbone carrier

Answer 2

the service provider that provides the segment of the backbone network to the other provider

Question 3

customer carrier

Answer 3

the service provider that connects with a larger backbone carrier

Question 4

T/F: A smaller service provider acts as a customer for a larger service provider.

Answer 4

True

Question 5

T/F: Many customer carrier sites, also called point-of-presence (POP) sites, can interconnect through the backbone carrier.

Answer 5

True

Question 6

Name some benefits of CSC.

Answer 6

• you can use a single CSC backbone to connect many POP sites
• You can use an MPLS VPN to separate traffic from the POP sites of various carriers
• A single CSC backbone can provide services to both VPN service providers and the ISP
• The customer service providers have no need to operate their own long-distance network
• Various customer carriers can use various addressing schemes, and the customer carriers reside in separate MPLS VPNs inside the CSC backbone
• You can use any link type that MPLS supports inside the CSC backbone and as access links between the CSC backbone and customer carriers.

Question 7

Describe how a customer carrier connects to a backbone carrier with LDP and an IGP.

Answer 7

• you must enable MPLS on the link between the backbone carrier and the customer carrier. LDP is the mechanism for label distribution.
• IGP is for route exchange

Question 8

Describe how a customer carrier connects to a backbone carrier with MP-EBGP.

Answer 8

• Use MP-EBGP for label and route exchange
• You must disable LDP on the links that connect the customer carrier and the backbone carrier networks, because the two label-signaling methods are mutually exclusive

Question 9

What is true about CSC MPLS VPN services?

A. A smaller service provider can act as a customer for a larger service provider.
B. The customer service providers operate their own long-distance network.
C. Various customer carriers must have the same addressing schemes.
D. Customer carriers are in the same MPLS VPNs inside the CSC backbone.

Answer 9

A