Information Technology Reference
In-Depth Information
Without CGMP
With CGMP
Si
Si
A
B
C
D
A
B
C
D
Figure 3-19
CGMP
IGMP Snooping
IGMP snooping is another way for switches to control multicast traffic at Layer 2. IGMP
snooping has become the preferred solution over CGMP. With IGMP snooping, switches
listen to IGMP messages between the hosts and routers. If a host sends an IGMP query
message to the router, the switch adds the host to the multicast group and permits that
port to receive multicast traffic. The port is removed from multicast traffic if an IGMP
leave message is sent from the host to the router. The disadvantage of IGMP snooping is
that it must listen to every IGMP control message, which can impact the switch's CPU
utilization.
10Gigabit Alliance,
www.10gea.org.
Cisco Data Center Network Architecture and Solutions Overview,
www.cisco.com/en/US/
“CSMA/CD Access Method, IEEE 802.3-2005.” New York, NY: Institute of Electrical and
Electronics Engineers, 2005.
IEEE P802.3ae 10Gb/s Ethernet Ta s k Force,
http://grouper.ieee.org/groups/802/3/ae/
“Token-Ring Access Method, IEEE 802.5-1998.” Piscataway, NJ: Institute of Electrical
and Electronics Engineers, 1998.
