Concept Guide

Protocol Ethernet Address
OSPF
01:00:5e:00:00:05
01:00:5e:00:00:06
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 EMC Networking OS implementation of MTRACE is in accordance with IETF draft draft-fenner-traceroute-ipm.
• Multicast is not supported on secondary IP addresses.
• If you enable multicast routing, egress Layer 3 ACL is not applied to multicast data trac.
• Multicast trac can be forwarded to a maximum of 15 VLANs with the same outgoing interface.
Dell EMC Networking OS does not support multicast routing in the following VLT scenarios:
• In a VLT enabled PIM router, multicast routing is not supported when there are multiple PIM spanned paths to reach source or RP. The
workaround is to congure only one PIM spanned path to reach any PIM router in the aggregation or spine.
• If a source is connected to a non-spanned interface of the VLT peer nodes and the RP is reachable on a spanned interface from both
the VLT nodes, there is a possibility to receive duplicate trac on the source. To avoid this, you should congure the source to be
reachable on a spanned interface.
Multicast Policies
The Dell EMC Networking OS supports multicast features for IPv4.
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, the Dell EMC Networking OS does not process Internet group
management protocol (IGMP) or multicast listener discovery protocol (MLD) joins to protocol-independent multicast (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 multicast
source discovery protocol (MSDP).
• If you increase the limit after it is reached, subsequent join requests are accepted. In this case, increase the limit by at least 10% for
IGMP and MLD to resume.
• If you decrease the limit after it is reached, the Dell EMC Networking OS does not clear the existing sessions. Entries are cleared after a
timeout (you may also clear entries using the clear ip mroute command).
Multicast Features
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