Overview of IPv4 Multicast Route Management
Definition
Multicast route management refers to the control of multicast packet forwarding by creating or changing multicast routes, as well as checking and maintaining multicast forwarding paths.
Purpose
Multicast route management ensures that multicast packets are forwarded efficiently through the correct paths.
In multicast routing and forwarding, each multicast routing protocol creates and maintains its own routing table. The routing information from these tables is then used to create a general multicast routing table. Multicast routers use this general multicast routing table to determine optimal routes, according to multicast routing and forwarding policies. The optimal route information is then delivered to the multicast forwarding information base (MFIB), where multicast data forwarding is controlled.
The MFIBs of network devices maintain a point-to-multipoint forwarding tree for the entire network, with a multicast source as the root and group members as leaves. Table 7-1 describes functions of multicast route management.
| Function | Description |
|---|---|
Reverse Path Forwarding (RPF) check |
Ensures that multicast data is forwarded through correct paths. |
Multicast static route |
Changes or connects multicast RPF routes. |
Multicast load splitting |
Distributes multicast data to multiple equal-cost routes to reduce the load on individual paths. |
Multicast over GRE |
Establishes a Generic Routing Encapsulation (GRE) tunnel between multicast routers to transmit multicast data across a unicast network segment. |
Multicast ping |
Detects group members on the network. |
Multicast Tracert |
Tracks the path to a multicast receiver along a multicast forwarding tree. |