ARP
What is the Centillion 1200N Switch?
2-10
Centillion 1200N ATM Switch User Manual
NTP 297-8103-903
ARP
Address Resolution Protocol (ARP) is an address conversion protocol used to
resolve the MAC address (or ATM address) of a terminal from its IP address in a
subnet. ARP provides IPOA function which conforms to RFC 1577.
The ARP function provided by the Server Card is to resolve the ATM addresses of
terminals in ATM-LAN. This function, in particular, is referred to as ATM ARP.
At least one ARP server is placed in a logical IP subnet (LIS). Having an ARP table
(IP address-ATM address chart) that is periodically updated, the ARP server
resolves addresses of terminals in that LIS.
Shown in
Figure 2-9
is the address resolution procedure using an ARP server. (The
numbers correspond with the procedures that follow.)
Figure 2-9: Address Resolution Procedure Using an ARP Server
1.
Each terminal, when connected to ATM-LAN, registers its own IP address and
ATM address with the ARP server. The ARP server uses the registered
addresses to prepare an ARP table.
2.
When the transmission terminal has no connection with the destination
terminal and has not cached the ATM address of the destination terminal, it
sends to the ARP server an address resolution request with the destination
terminal's IP address.
3.
The ARP server, after receiving the address resolution request, checks the ARP
table to see if there is an entry corresponding to the IP address. If there is, the
ARP server notifies the terminal of the ATM address corresponding to the
received IP address.
