If the multipoint network has differing speeds allocated to the VCs, a more complex solution is needed. There are two main approaches.
• To take the lowest CIR and to simply multiply this by the number of circuits. This is applied to the physical interface. The problem with this configuration is that the higher-bandwidth links will be underutilized for some things.
• If possible, it is much easier to configure and manage an environment that has used subinterfaces, where a VC is logically treated as if it were a separate interface or point-to point. The bandwidth command may be configured on each subinterface, which allows different speeds on each VC. In this second solution, subinterfaces are configured for the links with the differing CIRs. The links that have the same configured CIR are presented as a single subinterface with a bandwidth, which reflects the aggregate CIR of all the circuits.
Cisco recommends this as the preferred solution. The following syntax shows the structure of the bandwidth command:
interface S0 bandwidth speed of line
Was this article helpful?