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.
PPP Bandwidth Allocation Protocol (BAP) and Bandwidth Allocation Control Protocol (BACP)
(Page 2 of 2)
BACP Operation: Configuring the Use of BAP
Let's start with BACP, since it is
the protocol used for initial setup of the feature. BACP is very similar
in general concept to all those other PPP protocols with Control
in their names, such as LCP,
but is actually even simpler. It is used only during link configuration
to set up BAP. This is done using Configure-Request, Configure-Ack,
Configure-Nak and Configure-Reject messages just as described
in the LCP topic. The only configuration option that is negotiated in
BACP is one called Favored-Peer, which is used to ensure that
the two devices on the link don't get stuck if each tries
to send the same request at the same time.
If both devices support BAP then
the BACP negotiation will succeed and BAP will be activated.
BAP Operation: Adding and Removing Links
BAP defines a special set of messages
that can be sent between devices to add or drop links to/from the current
PPP bundle. What's particularly interesting about BAP is that it includes
the tools necessary to have a device actually initiate different types
of physical layer connections (such as dialing a modem for bundled analog
links or enabling an extra ISDN channel) when more bandwidth is required,
and then shut them down when no longer needed.
A brief description of the BAP message
- Call-Request and Call-Response:
When one device on the link wants to add a link to the bundle and initiate
the new physical layer link itself, it sends a Call-Request frame
to tell the other device, which replies with a Call-Response.
- Callback-Request and Callback-Response:
These are just like the two message types above, but used when a device
wants its peer (the other device on the link) to initiate the call to
add a new link. So, if device A says I need more bandwidth but
I want you to call me, instead of me calling you, it sends device
B a Callback-Request.
- Call-Status-Indication and Call-Status-Response:
After a device attempts to add a new link to the bundle (after sending
a Call-Request or receiving a Callback-Request) it reports
the status of the new link using the Call-Status-Indication frame.
The other device then replies with a Call-Status-Response.
- Link-Drop-Query-Request and Link-Drop-Query-Response:
These messages are used by one device to request that a link be dropped
and the other to respond to that request.
I should also point out that the
decision of when to add or remove links is not made by these protocols.
It is left up to the particular implementation.
|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.