Routing With Classical Ip Over Atm; About Logical Ip Subnets (Liss); Atm Arp Servers - 3Com LANPLEX 2500 EXTENDEDPLEX®2500 EXTENDED User Manual

4-10 C 4: R
HAPTER OUTING WITH
Routing with
Classical IP over
ATM
About Logical IP
Subnets (LISs)

ATM ARP Servers

IP T
ECHNOLOGY
LANPlex Extended Switching software supports classical IP routing over ATM
ARP in an ATM network. Classical IP over ATM uses Logical IP Subnets (LISs)
to forward packets within the network environment.
See the LANplex® 2500 Operation Guide for detailed information about the
ATM protocol architecture. See the LANplex® 2500 Administration Console
User Guide for information about how to configure ATM ports.
An LIS is a group of IP nodes that belong to the same subnet, and which are
directly connected to a single ATM network. When you add a node to a LIS
through the Administration Console IP interface menu, you define its IP
address, subnet mask, and the address an ATM ARP server that supports it.
An ATM ARP server maintains a table of IP addresses and their
corresponding ATM addresses and circuit information. To forward IP
packets over an ATM interface, the network node learns the ATM address for
the corresponding IP address from the ATM ARP server.
Each ATM ARP server supports a single LIS. You can associated two or more
LISs with the same ATM network, but each LIS operates independently of
other LISs on the network.
Several types of network nodes can function as ATM ARP servers:
Any LANplex system with revision 8.1.0 or later of Extended Switching
software
An ATM switch
A UNIX® workstation
The following sequence describes how the ATM ARP server learns and
stores information about the IP and ATM addresses of nodes in the network.
A node establishes a connection to the ATM ARP server
The ATM ARP server sends an inverse ATM ARP request to the node,
requesting its IP and ATM address
When the node returns this information, the ATM ARP server stores, or
caches, it in the ATM ARP server table.