Multimedia Traffic Control with IP Multicast (IGMP) 
Excluding Well-Known or Reserved Multicast Addresses from IP Multicast Filtering 
Excluding Well-Known or Reserved 
Multicast Addresses from IP Multicast 
Filtering 
Each multicast host group is identified by a single IP address in the range of 
224.0.0.0 through 239.255.255.255. Specific groups of consecutive addresses 
in this range are termed “well-known” addresses and are reserved for pre-
defined host groups. IGMP does not filter these addresses, so any packets the 
switch receives for such addresses are flooded out all ports assigned to the 
VLAN on which they were received (except the port on which the packets 
entered the VLAN). 
The following table lists the 32 well-known address groups (8192 total 
addresses) that IGMP does not filter on the Series 5300XL switches, as well 
as on the 1600M, 2400M, 2424M, 2650M, 4000M, 4100GL, 6108M, 8000M, and 
Series 2500 switches. 
Table 4-2.IP Multicast Address Groups Excluded from IGMP Filtering 
Groups of Consecutive  Groups of Consecutive 
Addresses in the Range of  Addresses in the Range of 
224.0.0.X to 239.0.0.X*  224.128.0.X to 239.128.0.X* 
224.0.0.x  232.0.0.x  224.128.0.x  232.128.0.x 
225.0.0.x  233.0.0.x  225.128.0.x  233.128.0.x 
226.0.0.x  234.0.0.x  226.128.0.x  234.128.0.x 
227.0.0.x  235.0.0.x  227.128.0.x  235.128.0.x 
228.0.0.x  236.0.0.x  228.128.0.x  236.128.0.x 
229.0.0.x  237.0.0.x  229.128.0.x  237.128.0.x 
230.0.0.x  238.0.0.x  230.128.0.x  238.128.0.x 
231.0.0.x  239.0.0.x  231.128.0.x  239.128.0.x 
* X is any value from 0 to 255. 
4-20