Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 602

• The Dell Networking OS implementation of MTRACE is in accordance with IETF draft draft-fenner-traceroute-ipm. • Multicast is not supported on secondary IP addresses. • Egress L3 ACL is not applied to multicast data traffic if you enable multicast routing. First Packet Forwarding for Lossless Multicast All initial multicast packets are forwarded to receivers to achieve lossless multicast. When the Dell Networking system is the RP, and has receivers for a group G, it forwards all initial multicast packets for the group based on the (*,G) entry rather than discarding them until the (S,G) entry is created, making Dell Networking systems suitable for applications sensitive to multicast packet loss. NOTE: When a source begins sending traffic, the Source DR forwards the initial packets to the RP as encapsulated registered packets. These packets are forwarded via the soft path at a maximum rate of 70 packets/second. Incoming packets beyond this rate are dropped. Multicast Policies The Dell Networking OS supports multicast features for IPv4. IPv6 multicast is not supported. • IPv4 Multicast Policies IPv4 Multicast Policies The following sections describe IPv4 multicast policies. • Limiting the Number of Multicast Routes • Preventing a Host from Joining a Group • Rate Limiting IGMP Join Requests • Preventing a PIM Router from Forming an Adjacency • Preventing a Source from Registering with the RP • Preventing a PIM Router from Processing a Join Limiting the Number of Multicast Routes When the total number of multicast routes on a system limit is reached, Dell Networking OS does not process any IGMP or multicast listener discovery protocol (MLD) joins to PIM - though it still processes leave messages - until the number of entries decreases below 95% of the limit. When the limit falls below 95% after hitting the maximum, the system begins relearning route entries through IGMP, MLD, and MSDP. • If the limit is increased after it is reached, join subsequent join requests are accepted. In this case, increase the limit by at least 10% for IGMP and MLD to resume. • If the limit is decreased after it is reached, Dell Networking OS does not clear the existing sessions. Entries are cleared after a timeout (you may also clear entries using clear ip mroute). NOTE: Dell Networking OS waits at least 30 seconds between stopping and starting IGMP join processing. You may experience this delay when manipulating the limit after it is reached. When the multicast route limit is reached, Dell Networking OS displays the following: 3w1d13h: %RPM0-P:RP2 %PIM-3-PIM_TIB_LIMIT: PIM TIB limit reached. No new routes will be learnt until TIB level falls below low watermark. 3w1d13h: %RPM0-P:RP2 %PIM-3-PIM_TIB_LIMIT: PIM TIB below low watermark. Route learning will begin. To limit the number of multicast routes, use the following command. Multicast Features 602