First Packet Forwarding For Lossless Multicast; Multicast Policies; Ipv4 Multicast Policies - Dell Z9500 Configuration Manual

Protocol Ethernet Address
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.
• If you enable multicast routing, egress Layer 3 ACL is not applied to multicast data traffic.

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 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.

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 Requets
• 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 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 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 566