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 Book is Here... and Now On Sale!

The whole site in one document for easy reference!
The TCP/IP Guide

Custom Search







Table Of Contents  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 Version 6 (IPv6) / IP Next Generation (IPng)
                     9  IPv6 Datagram Encapsulation and Formatting

Previous Topic/Section
IPv6 Datagram Extension Headers
Previous Page
Pages in Current Topic/Section
1
2
Next Page
IPv6 Datagram Size, Maximum Transmission Unit (MTU), Fragmentation and Reassembly
Next Topic/Section

IPv6 Datagram Options
(Page 1 of 2)

In IPv4, all “extra” information required for various purposes is placed into the datagram in the form of options that appear in the IPv4 header. In IPv6, the new concept of extension headers is introduced; these headers take the place of many of the predefined IPv4 options. However, the concept of options is still maintained in IPv6, for a slightly different purpose. Options allow the IPv6 datagram to be supplemented with arbitrary sets of information that aren't defined in the regular extension headers. They provide maximum flexibility, allowing the basic IPv6 protocol to be extended in ways the designers never anticipated, with the goal of reducing the chances of the protocol becoming obsolete.

IPv6 Option Extension Header Types

I said that IPv6 options supplement extension headers; in fact, they are actually implemented as extension headers. There are two different ones used to encode options. These two headers only differ in terms of how the options they contain are to be processed by devices; otherwise, they are formatted the same and used in the same way.

The two extension header types are:

  • Destination Options: Contains options that are intended only for the ultimate destination of the datagram (and perhaps a set of routers specified in a Routing header, if present).

  • Hop-By-Hop Options: Contains options that carry information for every device (router) between the source and destination

Previous Topic/Section
IPv6 Datagram Extension Headers
Previous Page
Pages in Current Topic/Section
1
2
Next Page
IPv6 Datagram Size, Maximum Transmission Unit (MTU), Fragmentation and Reassembly
Next Topic/Section

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!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



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.