Reference Guide

470 | Multicast Features
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Both scenarios might be unacceptable depending on the multicast application. Beginning with the FTOS
versions above, 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.
Multicast Policies
FTOS offers parallel Multicast features for IPv4 and IPv6.
• IPv4 Multicast Policies
• IPv6 Multicast Policies
IPv4 Multicast Policies
• Limit the Number of Multicast Routes
• Prevent a Host from Joining a Group
• Rate Limit IGMP Join Requests
• Prevent a PIM Router from Forming an Adjacency
• Prevent a Source from Registering with the RP
• Prevent a PIM Router from Processing a Join
Limit the Number of Multicast Routes
When the limit is reached, FTOS does not process any IGMP or 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, you
must increase the limit by at least 10% for IGMP and MLD to resume.
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.
Task Command Syntax Command Mode
Limit the total number of multicast routes on the system.
ip multicast-limit
Range: 1-50000
Default: 15000
CONFIGURATION