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 Network Interface Layer (OSI Data Link Layer) Protocols
           9  TCP/IP Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP)
                9  Point-to-Point Protocol (PPP)
                     9  PPP Protocol Frame Formats

Previous Topic/Section
PPP Authentication Protocol (PAP, CHAP) Frame Formats
Previous Page
Pages in Current Topic/Section
1
234
Next Page
TCP/IP Network Interface / Internet "Layer Connection" Protocols
Next Topic/Section

PPP Multilink Protocol (MP) Frame Format
(Page 1 of 4)

Some devices are connected not by a single physical layer link but by two or more. These may be either multiple physical connections such as two connected pairs of modems, or multiplexed virtual layer one connections like ISDN B channels. In either case, the PPP Multilink Protocol (MP, which also goes by several aliases such as MLPPP and MLP) can be used to aggregate the bandwidth of these physical links to create a single, high-speed bundle. I describe how this is done in the operational topic on MP.


Table 41: PPP Multilink Protocol Fragment Frame Format

Field Name

Size (bytes)

Description

B

1/8 (1 bit)

Beginning Fragment Flag: When set to 1, flags this fragment as the first of the split-up PPP frame. It is set to 0 for other fragments.

E

1/8 (1 bit)

Ending Fragment Flag: When set to 1, flags this fragment as the last of the split-up PPP frame. It is set to 0 for other fragments.

Reserved

2/8 (2 bits)
OR
6/8 (6 bits)

Reserved: Not used, set to zero.

Sequence Number

1 1/2 (12 bits)
OR
3 (24 bits)

Sequence Number: When a frame is split up, the fragments are given consecutive sequence numbers so the receiving device can properly reassemble them.

Fragment Data

Variable

Fragment Data: The actual fragment from the original PPP frame.


After MP is configured and starts working, it operates by employing a strategy for dividing up regular PPP frames amongst the many individual physical links that comprise the MP bundle. This is usually accomplished by chopping up the PPP frames into pieces called fragments and spreading these fragments across the physical links. This allows the traffic on the physical links to be easily balanced.


Previous Topic/Section
PPP Authentication Protocol (PAP, CHAP) Frame Formats
Previous Page
Pages in Current Topic/Section
1
234
Next Page
TCP/IP Network Interface / Internet "Layer Connection" Protocols
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.