Administrator Guide
Multicast Features
NOTE: Multicast routing is supported on secondary IP addresses; it is not supported on IPv6.
NOTE: Multicast routing is supported across default and non-default virtual routing and forwarding (VRFs).
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
• Multicast Policies
• Understanding Multicast Traceroute (mtrace)
• Printing Multicast Traceroute (mtrace) Paths
• Supported Error Codes
• mtrace Scenarios
Enabling IP Multicast
Before enabling any multicast protocols, you must enable IP multicast routing. To enable multicast routing, use the following command.
• Enable multicast routing.
CONFIGURATION mode
ip multicast-routing
Implementation Information
Because protocol control trac in the Dell Networking OS is redirected using the MAC address, and multicast control trac and multicast
data trac might map to the same MAC address, the Dell Networking OS might forward data trac with certain MAC addresses to the
CPU in addition to control trac.
As the upper ve bits of an IP Multicast address are dropped in the translation, 32 dierent multicast group IDs 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 and 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
34
592 Multicast Features