Nov 23 2008
Carrier Supporting Carrier – CSC
Carrier Supporting Carrier architecture is about connecting a single SPs POP sites using another Service Providers network.
In Carrier Supporting Carrier terminology, the service provider who connects another service providers POP sites is known as the backbone carrier.
The service provider whos POPs are connected via the backbone carrier is known as the customer carrier.
You might be thinking, whats the difference between inter-AS MPLS VPN and CSC.
Differences include
CSC connectes another ISPs POPs and not end customer sites. One might argue that the customer carrier whose POPs require connecting is the backbone carries customer and hence Inter is the same as CSC. Even if we made that statement, CSC still differs from Inter-AS in that CSC involves using one backbone carrier. Inter-AS however used 2 distinct “backbones” and the focus is how to connect these backbones. However looking at option 4 of Inter AS where you have a non VPN MPLS transit provider this is very similar to CSC.
Inter-AS MPLS VPN is only about MPLS VPN end customers, where as CSC is used for ISPs as well as VPN service providers.
Inter-AS MPLS VPN does not usually involve running MPLS between either the end customer and SPs or even between SPs themselves. Whereas CSC usually means running MPLS between the customer carrier and backbone carrier.
CSC also involves running an IGP between the backbone carrier and customer carrier. The IGP between the customer carrier and the backbone carrier is within a VRF on the backbone carrier side.
The backbone carrier can support multiple customer carriers.
There are two scenarios which require investigation.
- Customer Carrier is VPN service provider
- Customer Carrier is an Internet service provider and is not MPLS enabled
In all CSC scenarioes the backbone carrier is MPLS enabled.
Nov 23, 2008 @ 05:16:42
Well said? Great information, keep up the great work!