Please Whitelist This Site? I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :) If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads. If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK. Thanks for your understanding! Sincerely, Charles Kozierok Author and Publisher, The TCP/IP Guide

NOTE: Using software to mass-download the site degrades the server and is prohibited. If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Internet Layer (OSI Network Layer) Protocols            9  Internet Protocol (IP/IPv4, IPng/IPv6) and IP-Related Protocols (IP NAT, IPSec, Mobile IP)                 9  Internet Protocol Mobility Support (Mobile IP)

Mobile IP Agent Discovery, and Agent Advertisement and Solicitation Messages 1 2 3 4 Mobile IP Data Encapsulation and Tunneling

Registration Request Message Format

Registration Request messages have the format shown in Table 83 and Figure 132.

Table 83: Mobile IP Registration Request Message Format

Field Name	Size (bytes)	Description
Type	1	Type: Identifies the registration message type. For a request, this field is 1.
Flags	1
Lifetime	2	Lifetime: Length of time, in seconds, that the mobile node requests from the home agent for this registration.
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.
Home Agent	4	Home Agent: The IP address of the device acting as the mobile node's home agent.
Care-Of Address	4	Care-Of Address: The IP address being used by the mobile node as its care-of address.
Identification	8	Identification: A 64-bit number that uniquely identifies the Registration Request and is used to match requests to replies. It also provides protection against replay attacks; see the topic on Mobile IP security issues for more.
Extensions	Variable	Extensions: Extension fields are included here for authentication of the request. Other extensions may also be included.

Mobile IP Agent Discovery, and Agent Advertisement and Solicitation Messages 1 2 3 4 Mobile IP Data Encapsulation and Tunneling