ISDN PRI - 1.544 Mbps or 1.536 Mbps ? - TCP-IP

This is a discussion on ISDN PRI - 1.544 Mbps or 1.536 Mbps ? - TCP-IP ; "The Primary Rate Interface consists of 23 B-channels and one 64 kbit/s D-channel using a T1 line. Thus, a Primary Rate Interface user on a T1 line can have up to 1.544 Mbit/s service." If you do the math: 23Bchannels ...

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Thread: ISDN PRI - 1.544 Mbps or 1.536 Mbps ?

  1. ISDN PRI - 1.544 Mbps or 1.536 Mbps ?

    "The Primary Rate Interface consists of 23 B-channels and one 64 kbit/s
    D-channel using a T1 line. Thus, a Primary Rate Interface user on a T1 line
    can have up to 1.544 Mbit/s service."

    If you do the math:
    23Bchannels x 64 + 1D channel x64 = 1536 kbps or 1.536Mbit/s.
    Even if you divide 1536 : 1024 still doesn't give 1.544 Mbps ....




  2. Re: ISDN PRI - 1.544 Mbps or 1.536 Mbps ?

    On Dec 19, 11:00 pm, "eager" wrote:
    > "The Primary Rate Interface consists of 23 B-channels and one 64 kbit/s
    > D-channel using a T1 line. Thus, a Primary Rate Interface user on a T1 line
    > can have up to 1.544 Mbit/s service."
    >
    > If you do the math:
    > 23Bchannels x 64 + 1D channel x64 = 1536 kbps or 1.536Mbit/s.
    > Even if you divide 1536 : 1024 still doesn't give 1.544 Mbps ....



    A T1 line has 8000 frames each second of 192 data bits. When
    channelized for voice or ISDN PRI, you have 8 bits for each of the 24
    channels in each frame. Each frame also has a framing bit. So
    193x8000=1.544mb/s, with 8000bps being overhead. Not unlike a 9600bps
    async link really being able to transmit 7680bps of "real" data
    (assuming N-8-1 format).

  3. Re: ISDN PRI - 1.544 Mbps or 1.536 Mbps ?


    wrote in message
    news:cdd97e9b-aed7-47d0-8e48-7dfe09f02ef7@i12g2000prf.googlegroups.com...
    > On Dec 19, 11:00 pm, "eager" wrote:
    >> "The Primary Rate Interface consists of 23 B-channels and one 64 kbit/s
    >> D-channel using a T1 line. Thus, a Primary Rate Interface user on a T1
    >> line
    >> can have up to 1.544 Mbit/s service."
    >>
    >> If you do the math:
    >> 23Bchannels x 64 + 1D channel x64 = 1536 kbps or 1.536Mbit/s.
    >> Even if you divide 1536 : 1024 still doesn't give 1.544 Mbps ....

    >
    >
    > A T1 line has 8000 frames each second of 192 data bits. When
    > channelized for voice or ISDN PRI, you have 8 bits for each of the 24
    > channels in each frame. Each frame also has a framing bit. So
    > 193x8000=1.544mb/s, with 8000bps being overhead. Not unlike a 9600bps
    > async link really being able to transmit 7680bps of "real" data
    > (assuming N-8-1 format).


    I do not know where you got that, but even so, PRI _uses_ T1 line, and every
    book out there says that PRI consists of 23 B-channels _64kbps_each_ and 1 D
    channel also _64kbps.




  4. Re: ISDN PRI - 1.544 Mbps or 1.536 Mbps ?

    eager wrote:
    > wrote in message
    > news:cdd97e9b-aed7-47d0-8e48-7dfe09f02ef7@i12g2000prf.googlegroups.com...
    >> On Dec 19, 11:00 pm, "eager" wrote:
    >>> "The Primary Rate Interface consists of 23 B-channels and one 64 kbit/s
    >>> D-channel using a T1 line. Thus, a Primary Rate Interface user on a T1
    >>> line
    >>> can have up to 1.544 Mbit/s service."
    >>>
    >>> If you do the math:
    >>> 23Bchannels x 64 + 1D channel x64 = 1536 kbps or 1.536Mbit/s.
    >>> Even if you divide 1536 : 1024 still doesn't give 1.544 Mbps ....

    >>
    >> A T1 line has 8000 frames each second of 192 data bits. When
    >> channelized for voice or ISDN PRI, you have 8 bits for each of the 24
    >> channels in each frame. Each frame also has a framing bit. So
    >> 193x8000=1.544mb/s, with 8000bps being overhead. Not unlike a 9600bps
    >> async link really being able to transmit 7680bps of "real" data
    >> (assuming N-8-1 format).

    >
    > I do not know where you got that, but even so, PRI _uses_ T1 line, and every
    > book out there says that PRI consists of 23 B-channels _64kbps_each_ and 1 D
    > channel also _64kbps.
    >
    >
    >


    Hi,

    24 * 64kbps + 8kbps management channel used by telco

    Hubert

  5. Re: ISDN PRI - 1.544 Mbps or 1.536 Mbps ?

    On Dec 20, 1:43 am, "eager" wrote:
    > > A T1 line has 8000 frames each second of 192 data bits. When
    > > channelized for voice or ISDN PRI, you have 8 bits for each of the 24
    > > channels in each frame. Each frame also has a framing bit. So
    > > 193x8000=1.544mb/s, with 8000bps being overhead. Not unlike a 9600bps
    > > async link really being able to transmit 7680bps of "real" data
    > > (assuming N-8-1 format).

    >
    > I do not know where you got that, but even so, PRI _uses_ T1 line, and every
    > book out there says that PRI consists of 23 B-channels _64kbps_each_ and 1 D
    > channel also _64kbps.



    Right, but what's your question? Just like I said, each T1 frame of
    192 data bits (of which there are 8000 each second), carries eight
    bits from each of the 24 (23B+1D) 64kbps channels in a PRI (assuming
    the T1 is carrying a PRI, of course). And each frame has a 193rd bit
    for framing, which is the source of the 8000bps you were missing.

    The 193x8000 frame format is inherent in a T1. You can channelize
    that many different ways, but with voice-like circuits, the sub
    channels are invariably bit sliced across the frame in such a way that
    no jitter, burstyness, or lag is introduced. Remember that basic
    voice service is 8000 eight bit samples per second, and that you'll
    find line/frame formats all over the (telco) network synchronized in
    some fashion to the 8000 samples-per-second rate for the precise
    reason that you can carry that data rate without jitter, burstyness,
    or lag.

  6. Re: ISDN PRI - 1.544 Mbps or 1.536 Mbps ?


    wrote in message
    news:a923bdbf-2cab-4cdb-bcf3-978f03ed409c@n20g2000hsh.googlegroups.com...
    > On Dec 20, 1:43 am, "eager" wrote:
    >> > A T1 line has 8000 frames each second of 192 data bits. When
    >> > channelized for voice or ISDN PRI, you have 8 bits for each of the 24
    >> > channels in each frame. Each frame also has a framing bit. So
    >> > 193x8000=1.544mb/s, with 8000bps being overhead. Not unlike a 9600bps
    >> > async link really being able to transmit 7680bps of "real" data
    >> > (assuming N-8-1 format).

    >>
    >> I do not know where you got that, but even so, PRI _uses_ T1 line, and
    >> every
    >> book out there says that PRI consists of 23 B-channels _64kbps_each_ and
    >> 1 D
    >> channel also _64kbps.

    >
    >
    > Right, but what's your question? Just like I said, each T1 frame of
    > 192 data bits (of which there are 8000 each second), carries eight
    > bits from each of the 24 (23B+1D) 64kbps channels in a PRI (assuming
    > the T1 is carrying a PRI, of course). And each frame has a 193rd bit
    > for framing, which is the source of the 8000bps you were missing.
    >
    > The 193x8000 frame format is inherent in a T1. You can channelize
    > that many different ways, but with voice-like circuits, the sub
    > channels are invariably bit sliced across the frame in such a way that
    > no jitter, burstyness, or lag is introduced. Remember that basic
    > voice service is 8000 eight bit samples per second, and that you'll
    > find line/frame formats all over the (telco) network synchronized in
    > some fashion to the 8000 samples-per-second rate for the precise
    > reason that you can carry that data rate without jitter, burstyness,
    > or lag.


    Thank you!



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