3Com LANPLEX 2500, User Manual

Page: 155 / 186

Administering the AARP Cache 12-7
Administering
the AARP Cache
AARP allows hardware addresses to be mapped to an AppleTalk protocol
address. AppleTalk uses dynamically assigned 24-bit addresses, unlike the
statically-assigned 48-bit addresses used by Ethernet and token ring.
To make the address mapping process easier, AARP uses an Address
Mapping Table (AMT). The most recently used addresses are maintained in
the AMT. If an address is not in the AMT, AARP sends a request to the
desired protocol address and the hardware address is added to the table
when the destination node replies.
AARP is also responsible for registering a node’s dynamically assigned
address on the network. This process is described below:
■
AARP randomly assigns an address.
■
AARP broadcasts AARP probe packets to this address to determine if
another node is already using the address.
■
If there is no reply, the address becomes that node’s address.
■
If there is a reply, AARP repeats this process until an available address is
discovered.
In the Administration Console, you can:
■
Display the cache
■
Remove entries
■
Flush the cache