HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example - PPP

This is a discussion on HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example - PPP ; Hello, I cancelled the previous message because there was a typo. If it now doubles, sorry for that. I have some doubts about the example of ABM information exchange with use of RNR in ISO4335 chapter B.9.1.4. The standard states ...

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Thread: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

  1. HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    Hello,
    I cancelled the previous message because there was a typo. If it now
    doubles, sorry for that.

    I have some doubts about the example of ABM information exchange with use of
    RNR in ISO4335 chapter B.9.1.4. The standard states a frame with poll bit
    set should be answered at the next possible opportunity with a frame where
    the F-bit is set.

    In my interpretation, the P/F-bit is interpreted as "P" if the frame
    contains the address of the receiver. If the frame contains the address of
    the sender, the P/F-bit is interpreted as "F".
    Am I right there?

    Now my doubts concerning example B.9.1.4 "ABM information exchange - Use of
    RNR":
    B sends "B,I2,1F", then "A,RR1,P" - which is answered with "B,I1,3P". In my
    opinion, the "B,I1,3P" starts after A has received "A,RR1,P" and must
    therefore be "A,I1,3F" because the Poll-Bit must be answered first. Could
    somebody explain me, why the "B,I1,3P" frame is sent instead?

    Thanks,
    Michael B.




  2. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    "Michael Bruschkewitz" writes:
    > I have some doubts about the example of ABM information exchange with use of
    > RNR in ISO4335 chapter B.9.1.4. The standard states a frame with poll bit
    > set should be answered at the next possible opportunity with a frame where
    > the F-bit is set.


    Yes.

    > In my interpretation, the P/F-bit is interpreted as "P" if the frame
    > contains the address of the receiver. If the frame contains the address of
    > the sender, the P/F-bit is interpreted as "F".
    > Am I right there?


    Actually, the distinction is between "command" and "response." If
    it's a command, then it's the "P" bit. If it's a response, then it's
    the "F" bit.

    Telling command from response can be a little tricky as it varies a
    bit by mode and by specific implementation. There's usually a C/R bit
    reserved as part of the address field, though.

    For ABM, I think you're right about how the addressing is used.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  3. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example


    James Carlson wrote:
    > "Michael Bruschkewitz" writes:


    Does ABM stand for "Asynchronous Balanced Mode"?

    And there was a command, IIRC, SABM=Set Aynchronous Balanced Mode.

    I can believe this stuff is still alive. It's 2005 now.

    I'd be curious to know who still uses this.

    -Le Chaud Lapin-


  4. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    "Le Chaud Lapin" writes:
    > James Carlson wrote:
    > > "Michael Bruschkewitz" writes:

    >
    > Does ABM stand for "Asynchronous Balanced Mode"?


    Yes.

    > And there was a command, IIRC, SABM=Set Aynchronous Balanced Mode.


    And SABME (for extended addressing).

    > I can believe this stuff is still alive. It's 2005 now.
    >
    > I'd be curious to know who still uses this.


    All sorts of stuff does. V.120 is one standard that does.

    Yeah, I sort of wish the world would get with it and ditch things
    other than simple bit-synchronous HDLC-like encapsulation with PPP,
    but it'll take a while. I wouldn't be entirely shocked to see AC
    signaling used in some areas ... and you would have thought that blue
    boxing in the 1960's would have pretty much burned off that gear.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  5. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    There are development processes which last very long.
    There are applications which must work for thousands/millions of hours
    without interruptions.
    These software now/still must be validated.

    Why invent something new to replace, for example, gravity?
    The HDLC-standard dates 1993, this was just before lunch.

    "Le Chaud Lapin" schrieb im Newsbeitrag
    news:1132678632.282798.56780@g47g2000cwa.googlegro ups.com...
    >
    > James Carlson wrote:
    >> "Michael Bruschkewitz" writes:

    >
    > Does ABM stand for "Asynchronous Balanced Mode"?
    >
    > And there was a command, IIRC, SABM=Set Aynchronous Balanced Mode.
    >
    > I can believe this stuff is still alive. It's 2005 now.
    >
    > I'd be curious to know who still uses this.
    >
    > -Le Chaud Lapin-
    >




  6. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    "Michael Bruschkewitz" writes:
    > There are development processes which last very long.
    > There are applications which must work for thousands/millions of hours
    > without interruptions.
    > These software now/still must be validated.
    >
    > Why invent something new to replace, for example, gravity?
    > The HDLC-standard dates 1993, this was just before lunch.


    The current one, perhaps, but HDLC is _far_ older than that. Heck,
    even PPP is older than that!

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  7. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    >> Why invent something new to replace, for example, gravity?
    >> The HDLC-standard dates 1993, this was just before lunch.

    >
    > The current one, perhaps, but HDLC is _far_ older than that. Heck,
    > even PPP is older than that!


    Hmm, maybe I should use Algol60...



  8. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335 example

    In comp.protocols.tcp-ip Michael Bruschkewitz wrote:
    >>> Why invent something new to replace, for example, gravity?
    >>> The HDLC-standard dates 1993, this was just before lunch.

    >>
    >> The current one, perhaps, but HDLC is _far_ older than that. Heck,
    >> even PPP is older than that!


    > Hmm, maybe I should use Algol60...


    _REAL_ programmers use a wire-wrap tool

    rick jones
    --
    Wisdom Teeth are impacted, people are affected by the effects of events.
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  9. Re: HDLC-(ABM)-Addressing, Poll-Final-Bit, doubts about ISO/IEC4335example

    Rick Jones wrote:

    > In comp.protocols.tcp-ip Michael Bruschkewitz wrote:
    > >>> Why invent something new to replace, for example, gravity?
    > >>> The HDLC-standard dates 1993, this was just before lunch.
    > >>
    > >> The current one, perhaps, but HDLC is _far_ older than that. Heck,
    > >> even PPP is older than that!

    >
    > > Hmm, maybe I should use Algol60...

    >
    > _REAL_ programmers use a wire-wrap tool
    >
    > rick jones
    > --
    > Wisdom Teeth are impacted, people are affected by the effects of events.
    > these opinions are mine, all mine; HP might not want them anyway...
    > feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...


    I still have my Gardner Denver battery operated gun, my AC powered gun, a
    pair of NoNiks strippers (even though OK made some better ones) and of
    course the a few dewrap tools. I think logic speed was what killed
    wirewrap.

    There is a region in New Zealand called the Wairarapa and people there are
    caller - well, you guessed it!

    Blakely


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