CSC Interface

From the point of view of the CSC-PE, the IP/MPLS interface between the CSC-PE and a CSC-CE has these characteristics:

  1. The CSC interface is associated with one (and only one) VPRN service. Routes with the CSC interface as next-hop are installed only in the routing table of the associated VPRN.

  2. The CSC interface supports EBGP or IBGP for exchanging labeled IPv4 routes (RFC 3107). The BGP session may be established between the interface addresses of the two routers or else between a loopback address of the CSC-PE VRF and a loopback address of the CSC-CE. In the latter case, the BGP next-hop is resolved by either a static or OSPFv2 route.

  3. An MPLS packet received on a CSC interface is dropped if the top-most label was not advertised over a BGP (RFC 3107) session associated with one of the VPRN’s CSC interfaces.

  4. The CSC interface supports ingress QoS classification based on 802.1p or MPLS EXP. It is possible to configure a default FC and default profile for the CSC interface.

  5. The CSC interface supports QoS (re)marking for egress traffic. Policies to remark 802.1p or MPLS EXP based on forwarding-class and profile are configurable per CSC interface.

  6. By associating a port-based egress queue group instance with a CSC interface, the egress traffic can be scheduled/shaped with per-interface, per-forwarding-class granularity.

  7. By associating a forwarding-plane based ingress queue group instance with a CSC interface, the ingress traffic can be policed to per-interface, per-forwarding-class granularity.

  8. Ingress and egress statistics and accounting are available per CSC interface. The exact set of collected statistics depends on whether a queue-group is associated with the CSC interface, the traffic direction (ingress vs. egress), and the stats mode of the queue-group policers.

An Ethernet port or LAG with a CSC interface can be configured in hybrid mode or network mode. The port or LAG supports null, dot1q or qinq encapsulation. To create a CSC interface on a port or LAG in null mode, the following commands are used:

config>service>vprn>nw-if>port port-id config>service>vprn>nw-if>lag lag-id

To create a CSC interface on a port or LAG in dot1q mode, the following commands are used:

config>service>vprn>nw-if>port port-id:qtag1 config>service>vprn>nw-if>lag port-id:qtag1

To create a CSC interface on a port or LAG in qinq mode, the following commands are used:

config>service>vprn>nw-if>port port-id:qtag1.qtag2 config>service>vprn>nw-if>port port-id:qtag1.* config>service>vprn>nw-if>lag port-id:qtag1.qtag2 config>service>vprn>nw-if>lag port-id:qtag1.*

A CSC interface supports the same capabilities (and supports the same commands) as a base router network interface except it does not support:

Parent topic: Carrier Supporting Carrier (CSC)