Field Name

Size (bytes)

Description

Type

1

Type: Identifies the registration message type. For a reply, this field is 3.

Code

1

Code: Indicates the result of the registration request. This field is set to 0 if the registration was accepted, 1 if it was accepted but simultaneous bindings were requested and are not supported. If the registration was denied, a different reason code is provided that indicates the reason for the rejection, as well as whether it was the home agent or foreign agent that denied it.

Lifetime

2

Lifetime: If the registration was accepted, the length of time in seconds until the registration expires. This may of course be a different value than the mobile node requested.

Home Address

4

Home Address: The home (normal) IP address of the mobile node when on its home network. Uniquely identifies the device regardless of how the request is conveyed to the home agent, so the message can be delivered to it if multiple mobile nodes are served by the same foreign agent.

Home Agent

4

Home Agent: The IP address of the device acting as the mobile node's home agent.

Identification

8

Identification: A 64-bit number that uniquely identifies the Registration Reply and is matched to the Identification field of the request that precipitated it.

Extensions

Variable

Extensions: Extension fields are included here for authentication of the reply. Other extensions may also be included.