PPP - HDLC framing and HDLC protocol? - PPP

This is a discussion on PPP - HDLC framing and HDLC protocol? - PPP ; I have taken a look at the PPP RFC but am still not sure about the answer to this question. I thought you might be able to provide a quick answer. I am trying to determine if an asynch PPP ...

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Thread: PPP - HDLC framing and HDLC protocol?

  1. PPP - HDLC framing and HDLC protocol?

    I have taken a look at the PPP RFC but am still not sure about the
    answer to this question. I thought you might be able to provide a quick
    answer.


    I am trying to determine if an asynch PPP link that uses HDLC framing
    (Windows dial-up networking for instance) also includes HDLC protocol
    behavior.

    For example, does PPP include all of the HDLC supervisory commands and
    responses (Receive Ready, Receive Not Ready, Reject, Selective Reject)
    or any of the UNNUMBERED FORMAT COMMANDS RESPONSES (Set Normal Response
    Mode, Set Asynchronous Response Mode, Set Asynchronous Balanced Mode,
    Disconnect, Set Normal Response Mode Extended, Set Initialization Mode,
    Unnumbered Poll, Unnumbered Information, Exchange Identification,
    Reset, Test, Unnumbered Acknowledgment, Disconnected Mode, Request
    Initialization Mode, Request Disconnect, Frame Reject)?


  2. Re: PPP - HDLC framing and HDLC protocol?

    In article <1108050740.820923.186030@c13g2000cwb.googlegroups. com>,
    MarkF wrote:
    >I have taken a look at the PPP RFC but am still not sure about the
    >answer to this question. I thought you might be able to provide a quick
    >answer.
    >
    >
    >I am trying to determine if an asynch PPP link that uses HDLC framing
    >(Windows dial-up networking for instance) also includes HDLC protocol
    >behavior.
    >
    >For example, does PPP include all of the HDLC supervisory commands and
    >responses (Receive Ready, Receive Not Ready, Reject, Selective Reject)
    >or any of the UNNUMBERED FORMAT COMMANDS RESPONSES (Set Normal Response
    >Mode, Set Asynchronous Response Mode, Set Asynchronous Balanced Mode,
    >Disconnect, Set Normal Response Mode Extended, Set Initialization Mode,
    >Unnumbered Poll, Unnumbered Information, Exchange Identification,
    >Reset, Test, Unnumbered Acknowledgment, Disconnected Mode, Request
    >Initialization Mode, Request Disconnect, Frame Reject)?


    Nope. Just the format of the frame is used. Other then the address and
    control field (which is ALWAYS 0xff 0x03), the protocol field and the
    16-bit CRC, you don't have to do anything else to support this HDLC
    framing for PPP. (somebody will slap me if I've stated it too generally?)

    ========= For LAN/WAN Protocol Analysis, check out PacketView Pro! =========
    Patrick Klos Email: patrick@klos.com
    Klos Technologies, Inc. Web: http://www.klos.com/
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  3. Re: PPP - HDLC framing and HDLC protocol?

    pklos@osmium.mv.net (Patrick Klos) writes:
    > >For example, does PPP include all of the HDLC supervisory commands and
    > >responses (Receive Ready, Receive Not Ready, Reject, Selective Reject)
    > >or any of the UNNUMBERED FORMAT COMMANDS RESPONSES (Set Normal Response
    > >Mode, Set Asynchronous Response Mode, Set Asynchronous Balanced Mode,
    > >Disconnect, Set Normal Response Mode Extended, Set Initialization Mode,
    > >Unnumbered Poll, Unnumbered Information, Exchange Identification,
    > >Reset, Test, Unnumbered Acknowledgment, Disconnected Mode, Request
    > >Initialization Mode, Request Disconnect, Frame Reject)?

    >
    > Nope. Just the format of the frame is used. Other then the address and
    > control field (which is ALWAYS 0xff 0x03), the protocol field and the
    > 16-bit CRC, you don't have to do anything else to support this HDLC
    > framing for PPP. (somebody will slap me if I've stated it too generally?)


    See RFCs 1662 and 1663.

    You do the HDLC blood-and-chicken dances when you're using "numbered
    mode," or when you're running over some medium that requires it (such
    as PPP over X.25). Otherwise, no, standard PPP uses an "HDLC-like"
    encapsulation -- and the "like" part means that it just uses the
    framing and doesn't include any of the command/response bits.

    If all you're interested in is async PPP as done by Windoze, that's
    RFC 1662.

    --
    James Carlson, IP Systems Group
    Sun Microsystems / 1 Network Drive 71.234W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.497N Fax +1 781 442 1677

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