# Port-Level Admission Bandwidth Limits for IPv6 Overview

Port-level multicast admission control is performed when an outgoing (OIF) on that port is added to the mroute for a given (S,G) multicast data stream and the multicast bandwidth map contains a set admission-bandwidth action for that (S,G).

When enabled, the admission-bandwidth for a particular (S,G) is read from the multicast bandwidth map and recorded in the mroute when the (S,G) mroute is created. When an IOF is subsequently added to the mroute, the OIF is blocked from forwarding data if the additional bandwidth contributed by the (S,G) would exceed the admission-bandwidth limit for the port on which the interface resides.

| Caution: Before you can limit port-level admission bandwidth, you must first create a bandwidth map. See Example: Configuring an IPv6 Multicast Bandwidth Map for details.

#### Related Documentation

- Enabling Port-Level Admission Bandwidth Limitation for IPv6
- OIF Port Reevaluation for IPv6
- set admission-bandwidth