Users Guide
37
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)
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 trac in Dell Networking OS is redirected using the MAC address, and multicast control trac and
multicast data trac might map to the same MAC address, Dell Networking OS might forward data trac with certain MAC
addresses to the CPU in addition to control trac.
As the upper5 bits of an IP Multicast address are dropped in the translation, 32 dierent 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 rst (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 dierentiate multicast control trac multicast data trac with the same address, so
if you use IP address 225.0.0.5 for data trac, both the multicast data and OSPF control trac 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.
• Multicast is not supported on secondary IP addresses.
• Egress L3 ACL is not applied to multicast data trac if you enable multicast routing.
562
Multicast Features