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.
Mobile IP Agent Discovery, and Agent Advertisement and Solicitation Messages
(Page 3 of 5)
Agent Solicitation Message Format
Lets start with the Agent
Solicitation message because it is much simpler. In fact, there
is no new message format defined for this at all; it is identical to
the format of a Router
The reason no new message type is
required here is that a solicitation is an extremely simple message:
hey, if there are any routers out there, please tell me who you
are and what you can do. No extra Mobile IP information needs
to be sent. When a regular IP router receives a Router Solicitation
it will send a Router Advertisement, but a Mobile IP router automatically
sends the longer Agent Advertisement instead when prompted by
any solicitation, whether it comes from a Mobile IP node or a regular
Agent Advertisement Message Format
The Agent Advertisement begins
with the normal fields of an ICMP
Router Advertisement message. The destination
of the message is either the all
devices multicast address (220.127.116.11)
if multicast is supported on the local network, or the broadcast address
(255.255.255.255) otherwise. The Router Address fields are filled
in with the address(es) of the agent.
Note: It is possible that a device may wish to advertise its ability to handle Mobile IP messages, but not act as a regular router. In this case it changes the normal Code field in the header of the Router Advertisement message from 0 to 16.
Following the regular fields, one
or more extensions are added to the message format. There are
three extensions defined: the Mobility Agent Advertisement Extension,
Prefix-Lengths Extension, and One-Byte Padding Extension.
|If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!|
Table Of Contents - Contact Us
The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005
© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.