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 Efficiency Issues
(Page 2 of 2)
Implications of Reverse Tunneling
To make matters worse, consider what
happens if reverse
tunneling is used! Here, tunneling is
done not just for datagrams sent to the mobile node but sent from it
as well. In our worst case example, a request/reply pair
from the mobile node to another device on the foreign network requires
two complete round-trips from Tokyo to London and back.
Clearly, this is far from ideal.
Inefficiency is an Inherent Part of Mobile IP
There really isn't any solution to
this problem within Mobile IP itself; it's just a natural consequence
of how the protocol works. The only way to really improve things is
to hack in a solution that ultimately boils down to one
of the two options we always have in IP without mobility support: we
either decide to give the mobile device a temporary real IP address
on the foreign network, or we use a host-specific route for the mobile
device while on the foreign network.
We've
already seen that these both have problems,
which is why Mobile IP was created in the first place. There may be
situations, however, where efficiency is more important than the transparent
portability that Mobile IP provides. For a long-term deployment on a
foreign network far from the home network, or for applications where
efficiency is paramount, it may make sense to employ one of these techniques.
For example, a corporation that has a small number of offices in different
cities connected using the Internet might set up special routing. This
would let mobile devices visiting from other cities talk directly to
nodes local to the foreign part of the network without being routed
across the Internet.
Key Concept: Since datagrams are sent to a mobile node at its home address, each datagram sent to the mobile device must first go back to its home network and then be forwarded to its current location. The level of inefficiency that results depends on how far the sender is from the mobiles home network. The worst case actually occurs if the sender and mobile are on the same foreign network, in which case each transmission must make a round-trip to the mobiles home network and then back again. This is an inherent part of how Mobile IP and cannot readily be rectified. |
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! |
|
|
Home -
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.
|