DELL S50V User Manual
Multicast Features | 665
Implementation Information
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Because protocol control traffic in FTOS is redirected using the MAC address, and multicast control
traffic and multicast data traffic might map to the same MAC address, FTOS might forward data traffic
with certain MAC addresses to the CPU in addition to control traffic.
traffic and multicast data traffic might map to the same MAC address, FTOS might forward data traffic
with certain MAC addresses to the CPU in addition to control traffic.
As the upper five 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 well known IP address for
OSPF that maps to the multicast MAC address 01:00:5e:00:00:05. However, 225.0.0.5, 226.0.0.5, etc.,
map to the same multicast MAC address. The Layer 2 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.
group IDs all map to the same Ethernet address. For example, 224.0.0.5 is a well known IP address for
OSPF that maps to the multicast MAC address 01:00:5e:00:00:05. However, 225.0.0.5, 226.0.0.5, etc.,
map to the same multicast MAC address. The Layer 2 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 ones
below.
below.
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The FTOS implementation of MTRACE is in accordance with IETF draft draft-fenner-traceroute-ipm.
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Multicast is not supported on secondary IP addresses.
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Egress L3 ACL is not applied to multicast data traffic if multicast routing is enabled.
Multicast Policies
FTOS offers parallel Multicast features for IPv4 and IPv6.
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IPv4 Multicast Policies
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Protocol Ethernet Address
OSPF
01:00:5e:00:00:05
01:00:5e:00:00:06
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