User`s guide

1-26
Introduction
upon the operating system or TCP/IP being used. The host
becomes aware of a gateway in one of three ways:
• The host is manually configured with a default gateway
address.
• The host is listening to Routing Information Protocol (RIP)
broadcasts.
• The host is participating in the router discovery protocol
(ICMP).
When using LCM each ATX port can be configured for zero or
more IP addresses, with associated subnet masks. Each IP address
defines an IP subnetwork. Each IP subnetwork is a distinct entity
with respect to protocols, such as RIP (Routing Information
Protocol), and is treated as a separate interface. Specifically:
• RIP advertisements are transmitted to each IP subnetwork
broadcast address of the IP addresses associated with a ATX
port. RIP advertisements include route descriptions of the other
IP subnetworks assigned to that ATX port. For example, if a ATX
port has three IP addresses assigned to it, three RIP
advertisements are transmitted each interval, and each RIP
advertisement publicizes the other two IP subnetworks.
• Router discovery ICMP packets are transmitted to either the
host’s IP multicast address, or to the local broadcast address,
regardless of how many IP addresses are assigned to an ATX
port. All IP subnetworks assigned to an ATX port are advertised
in each router discovery ICMP packet.
1.8.3 IP Multicast Routing
The Internet Protocol (IP) is recognized as the base technology for
multimedia applications.The implementation of IP multicast
routing complies with the DVMRP standard.
In general, IP multicasting is the transmission of IP packets to a
host group. A host group is a set of hosts identified by Class D IP