TP-Link T3700G-28TQ T3700G-28TQ V1 UG - Page 243
Neighbor Discovering, DR Electing, DR Elect
View all TP-Link T3700G-28TQ manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 243 highlights
Asserting Neighbor Discovering The neighbor discovering mechanism of PIM SM and PIM DM is the same, for more details, refer to Neighbor Discovering. DR Electing The DR (Designated Router) in the shared network is elected through the Hello message, and works as the exclusive router to forward multicast data in this shared network. Whether the network connects to the multicast source or the network connects to the receivers, the DR must be elected if the network is a shared one. The DR is responsible for sending join message to the RP in the receiver side and sending register message to the RP in the multicast source side. Note: The DR is elected between the multiple routers of the network segment by comparing the priorities and IP addresses carried in Hello packets. The elected DR has practical meaning in PIM SM; with PIM DM operation, the DR has meaning only if IGMPv1 is in use, the elected DR functions as the IGMP querier on account that IGMPv1 does not have an IGMP querier election process. The device working as DR should be enabled with the IGMP function; otherwise the receivers connected to it would be unable to join the multicast group via this DR. Figure 11-15 DR Elect As shown in Figure 11-15, the DR election process is illustrated below: (1) Routers in the shared network sends Hello message carrying DR-election priority to each other, and the router with the highest priority will be elected as the DR; (2) If the routers have the same priorities, or at least one route in the network doesn't support carrying the DR-election priority in the Hello packet, the routers with the highest IP address will be elected as the DR. 232