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Multicast Features
The Dell Networking operating system (OS) supports the following multicast protocols.
PIM Sparse-Mode (PIM-SM)
Internet Group Management Protocol (IGMP)
Multicast Source Discovery Protocol (MSDP)
Topics:
Enabling IP Multicast
Implementation Information
First Packet Forwarding for Lossless Multicast
IPv4 Multicast Policies
Understanding Multicast Traceroute (mtrace)
Printing Multicast Traceroute (mtrace) Paths
Supported Error Codes
mtrace Scenarios
Enabling IP Multicast
Enabling IP Multicast is supported on the S5000 switch.
Prior to enabling any multicast protocols, you must enable multicast routing.
Enable multicast routing.
CONFIGURATION mode
ip multicast-routing
Implementation Information
Because protocol control traffic in Dell Networking OS is redirected using the MAC address, and multicast control traffic and
multicast data traffic might map to the same MAC address, Dell Networking OS might forward data traffic with certain MAC
addresses to the CPU in addition to control traffic.
As the upper5 bits of an IP Multicast address are dropped in the translation, 32 different multicast group IDs all map to the
same Ethernet address. For example, 224.0.0.5 is a known IP address for open shortest path first (OSPF) that maps to the
multicast MAC address 01:00:5e:00:00:05. However, 225.0.0.5, 226.0.0.5, and so on, map to the same multicast MAC address.
The Layer 2 forwarding information base (FIB) alone cannot differentiate multicast control traffic multicast data traffic with the
same address, so if you use IP address 225.0.0.5 for data traffic, both the multicast data and OSPF control traffic match the
same entry and are forwarded to the CPU. Therefore, do not use well-known protocol multicast addresses for data transmission,
such as the following.
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 Networking OS implementation of MTRACE is in accordance with IETF draft draft-fenner-traceroute-ipm.
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