InARP, Inverse Address Resolution Protocol

Description Glossary RFCs Publications Obsolete RFCs


Protocol suite: TCP/IP.
Type:Network layer address resolution protocol.

InARP is an extension of the ARP protocol used by frame relay.

Basic InARP operates essentially the same as ARP with the exception that InARP does not broadcast requests. This is because the hardware address of the destination station is already known.

MAC header InARP packet

InARP packet:

0001020304050607 0809101112131415 1617181920212223 2425262728293031
Hardware type Protocol type
Hardware address length Protocol address length Opcode
Source hardware address :::
Source protocol address :::
Destination hardware address :::
Destination protocol address :::

Hardware type. 16 bits.

Protocol type. 16 bits.

Hardware address length. 8 bits.
Length of the hardware address in bytes.

Protocol address length. 8 bits.
Length of the protocol address in bytes.

Opcode. 16 bits.

Source hardware address. Variable length.

Source protocol address. Variable length.

Destination hardware address. Variable length.

Destination protocol address. Variable length.


DLCI, Data Link Connection Identifier.
The Frame Relay equivalent of a hardware address.


[RFC 2390] Inverse Address Resolution Protocol.


Obsolete RFCs:

[RFC 1293] Inverse Address Resolution Protocol.

[RFC 2625] IP and ARP over Fibre Channel.

Description Glossary RFCs Publications Obsolete RFCs