Administrator Guide

Protocol Ethernet Address
RIP 01:00:5e:00:00:09
NTP 01:00:5e:00:01:01
VRRP 01:00:5e:00:00:12
PIM-SM 01:00:5e:00:00:0d
•
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 trac if you enable multicast routing.
First Packet Forwarding for Lossless Multicast
All initial multicast packets are forwarded to receivers to achieve lossless multicast.
In previous versions, when the Dell Networking system is an RP, all initial packets are dropped until PIM creates an (S,G) entry. When the
system is an RP and a Source DR, these initial packet drops represent a loss of native data, and when the system is an RP only, the initial
packets drops represent a loss of register packets.
Both scenarios might be unacceptable depending on the multicast application. 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 trac, 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.
IPv4 Multicast Policies
The following sections describe IPv4 multicast policies.
• Limiting the Number of Multicast Routes
• Preventing a Host from Joining a Group
• 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.
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Multicast Features