Layer 3-Switched Multicast Packet Rewrite
When a multicast packet is Layer 3 switched from a multicast source to a destination multicast group, the PFC and the DFCs perform a packet rewrite that is based on information learned from the RP and stored in the adjacency table. For example, Server A sends a multicast packet addressed to IP multicast group G1. If there are members of group G1 on VLANs other than the source VLAN, the PFC must perform a packet rewrite when it replicates the traffic to the other VLANs (the sw..
The steps for configuring RIPng are the same as RIPv1 and v2: Create the routing process, enable the routing protocol on interfaces, and perform any desired customization. The commands, however, are very different. In fact, the creation of the routing process and enabling the routing protocol on the first interface is accomplished in one step, using an interface command. The case studies for RIPng will be similar to those of RIPv1 and v2 to illustrate the similarities in the ..
So far, this section on PIM-SM has explained the beginnings of the registration process, by which a router near the source of multicast packets registers with the RP. Before completing that discussion, however, the concept of the shared tree for a multicast group, also called the root-path tree (RPT), must be explained. As mentioned earlier, PIM-SM initially causes multicasts to be delivered in a two-step process: first, packets are sent from the source to the RP, and then th..
In 802.1D, BPDUs basically originate from the root bridge and are relayed by all switches down through the tree. Because of this propagation of BPDUs, 802.1D convergence must wait for steady-state conditions before proceeding. RSTP uses the 802.1D BPDU format for backward compatibility. However, some previously unused bits in the Message Type field are used. The sending switch port identifies itself by its RSTP role and state. The BPDU version also is set to 2 to distinguish..
Multicast over Frame Relay or ATM WANs
When using PIM-SM on an nonbroadcast multiple access (NBMA) network, such as a Frame Relay or ATM WAN, you must configure the ip pim nbma-mode interface command: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#ip multicast-routing Router1(config)#interface Serial0/0 Router1(config-if)#encapsulation frame-relay Router1(config-if)#ip pim sparse-mode Router1(config-if)#ip pim nbma-mode Router1(config-if)#end ..
