Ip Multicast Routing - Alcatel OmniSwitch 6800 Series Network Configuration Manual

IPMS Overview
Reserved Multicast Addresses
The Internet Assigned Numbers Authority (IANA) created the range for multicast addresses, which is
224.0.0.0 to 239.255.255.255. However, as the table below shows, certain addresses are reserved and
cannot be used.
Address or Address Range
224.0.0.0 through 224.0.0.255
224.0.1.0 through 224.0.1.255
224.0.2.0 through 224.0.255.0
224.1.0.0 through 224.1.255.255
224.2.0.0 through 224.2.255.255
224.252.000.000 through 224.255.255.255
225.000.000.000 through 231.255.255.255
232.000.000.000 through 232.255.255.255
233.000.000.000 through 233.255.255.255
234.000.000.000 through 238.255.255.255
239.000.000.000 through 239.255.255.255

IP Multicast Routing

IP multicast routing can be used for IP Multicast Switching and Routing (IPMSR). IP multicast routing is
a way of controlling multicast traffic across networks. The multicast router discovers which networks want
to receive multicast traffic by sending out Internet Group Management Protocol (IGMP) queries and
receiving IGMP reports from attached networks. The IGMP reports signal that users want to join a multi-
cast group.
If there is more than one multicast router in the network, the router with the lowest IP address is elected
the querier router, which is responsible for querying the subnetwork for group members.
The IP multicast routing package offers the following two separate protocols:
Protocol Independent Multicast — Sparse Mode (PIM-SM), which is described in
•
page 23-5.
Distance Vector Multicast Routing Protocol (DVMRP), which is described in
•
The multicast routing protocols build and maintain a multicast routing database. The multicast routing
protocols forward multicast traffic to networks that have requested group membership to a specific multi-
cast group. IPMS uses decisions made by the routing protocols and forwards multicast traffic to ports that
request group membership. See the OmniSwitch 6800 Series Advanced Routing Configuration Guide for
more information on IP multicast routing protocols.
page 23-4
Description
Routing protocols (e.g., OSPF, RIP2)
Internetwork Control Block (e.g., RSVP, DHCP, commer-
cial servers)
AD-HOC Block (e.g., commercial servers)
ST Multicast Groups
SDP/SAP Block
DIS Transient Groups
Reserved
Source Specific Multicast
GLOP Block
Reserved
Administratively Scoped
OmniSwitch 6800 Series Network Configuration Guide
Configuring IP Multicast Switching
"PIM-SM" on
"DVMRP" on page
November 2004
23-5.