convention for frame relay diagrams - cross posted from alt.certification.cisco

Discussion in 'Cisco' started by John Smith, Mar 12, 2005.

  1. John Smith

    John Smith Guest

    Hi,



    I've done the CCNA and am working on the CCNP bcran exam and I've got one
    major issue that steadfastly refuses to go away! When looking at diagrams
    of a frame relay network there appears to be no consistency in where the
    DLCI is drawn on the diagram. Sometimes the DLCI written above a link seems
    to mean the local dlci, whereas at other times it's the other ends DLCI.



    For example



    frame-relay map ip 10.10.12.2 200 broadcast cisco



    Sometimes has a diagram with the 200 drawn next to the 10.10.12.2 router, at
    other times the 200 is on the other side.



    This is an issue that I've have for months and I'm getting nowhere. Am I
    just stupid or is there no set convention?



    Yours confused.

    Paul
     
    John Smith, Mar 12, 2005
    #1
    1. Advertising

  2. John Smith

    Toby Guest

    "John Smith" <> wrote in message
    news:d0v3so$sgl$...
    > Hi,
    >
    >
    >
    > I've done the CCNA and am working on the CCNP bcran exam and I've got one
    > major issue that steadfastly refuses to go away! When looking at diagrams
    > of a frame relay network there appears to be no consistency in where the
    > DLCI is drawn on the diagram. Sometimes the DLCI written above a link
    > seems
    > to mean the local dlci, whereas at other times it's the other ends DLCI.
    >
    >
    >
    > For example
    >
    >
    >
    > frame-relay map ip 10.10.12.2 200 broadcast cisco
    >
    >
    >
    > Sometimes has a diagram with the 200 drawn next to the 10.10.12.2 router,
    > at
    > other times the 200 is on the other side.
    >
    >
    >
    > This is an issue that I've have for months and I'm getting nowhere. Am I
    > just stupid or is there no set convention?
    >
    >
    >
    > Yours confused.
    >
    > Paul
    >

    Paul

    You will be well aware that a DLCI is local to an interface.

    i.e.

    Site A - DLCI 16 --FR Cloud -- DLCI 16 Site B
    Site A - DLCI 17 --FR Cloud -- DLCI 16 Site C

    Site A uses 16 to reach Site B
    Site B uses 16 to reach Site A
    Site A uses 17 to reach Site C
    Site C uses 16 to reach Site A

    The above is a standard addressing scheme and you would see the DLCI's on
    the outgoing link on the diagram.


    There is another concept used to simplify understanding the destination of
    PVC's called global addressing. This is just a conceptual addressing and
    does not make frame-relay addressing work any different. It just means the
    DLCI's are picked intelligently and not just sequentially.

    For this we allocate each site an id.

    i.e.
    Site A = 101
    Site B = 102
    Site C = 103

    We then use the DLCI number of the site we intend to connect to.

    Site A - DLCI 102 --FR Cloud -- DLCI 101 Site B
    Site A - DLCI 103 --FR Cloud -- DLCI 101 Site C

    Site A uses 102 to reach Site B
    Site B uses 101 to reach Site A
    Site A uses 103 to reach Site C
    Site C uses 101 to reach Site A

    You could still label the DLCI on the outgoing link but now as you know that
    all DLCI 101 go to Site A, all DLCI 102 to site B etc. you can just label
    the site instead.

    Regards

    Toby
     
    Toby, Mar 13, 2005
    #2
    1. Advertising

  3. John Smith

    John Smith Guest

    thanks Toby, FWI anyone else interested this thread has continued on
    alt.certification.cisco



    "Toby" <> wrote in message
    news:ImUYd.68$...
    >
    > "John Smith" <> wrote in message
    > news:d0v3so$sgl$...
    >> Hi,
    >>
    >>
    >>
    >> I've done the CCNA and am working on the CCNP bcran exam and I've got one
    >> major issue that steadfastly refuses to go away! When looking at
    >> diagrams
    >> of a frame relay network there appears to be no consistency in where the
    >> DLCI is drawn on the diagram. Sometimes the DLCI written above a link
    >> seems
    >> to mean the local dlci, whereas at other times it's the other ends DLCI.
    >>
    >>
    >>
    >> For example
    >>
    >>
    >>
    >> frame-relay map ip 10.10.12.2 200 broadcast cisco
    >>
    >>
    >>
    >> Sometimes has a diagram with the 200 drawn next to the 10.10.12.2 router,
    >> at
    >> other times the 200 is on the other side.
    >>
    >>
    >>
    >> This is an issue that I've have for months and I'm getting nowhere. Am I
    >> just stupid or is there no set convention?
    >>
    >>
    >>
    >> Yours confused.
    >>
    >> Paul
    >>

    > Paul
    >
    > You will be well aware that a DLCI is local to an interface.
    >
    > i.e.
    >
    > Site A - DLCI 16 --FR Cloud -- DLCI 16 Site B
    > Site A - DLCI 17 --FR Cloud -- DLCI 16 Site C
    >
    > Site A uses 16 to reach Site B
    > Site B uses 16 to reach Site A
    > Site A uses 17 to reach Site C
    > Site C uses 16 to reach Site A
    >
    > The above is a standard addressing scheme and you would see the DLCI's on
    > the outgoing link on the diagram.
    >
    >
    > There is another concept used to simplify understanding the destination of
    > PVC's called global addressing. This is just a conceptual addressing and
    > does not make frame-relay addressing work any different. It just means the
    > DLCI's are picked intelligently and not just sequentially.
    >
    > For this we allocate each site an id.
    >
    > i.e.
    > Site A = 101
    > Site B = 102
    > Site C = 103
    >
    > We then use the DLCI number of the site we intend to connect to.
    >
    > Site A - DLCI 102 --FR Cloud -- DLCI 101 Site B
    > Site A - DLCI 103 --FR Cloud -- DLCI 101 Site C
    >
    > Site A uses 102 to reach Site B
    > Site B uses 101 to reach Site A
    > Site A uses 103 to reach Site C
    > Site C uses 101 to reach Site A
    >
    > You could still label the DLCI on the outgoing link but now as you know
    > that all DLCI 101 go to Site A, all DLCI 102 to site B etc. you can just
    > label the site instead.
    >
    > Regards
    >
    > Toby
    >
    >
     
    John Smith, Mar 13, 2005
    #3
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. blank

    How to eliminate cross-posted binaries?

    blank, Nov 9, 2003, in forum: Computer Support
    Replies:
    3
    Views:
    477
    Gary G. Taylor
    Nov 11, 2003
  2. microberts

    I found out why and how i cross posted.

    microberts, Dec 22, 2003, in forum: Computer Support
    Replies:
    3
    Views:
    442
    Blinky the Shark
    Dec 22, 2003
  3. DS

    Possible in OE to block cross posted items??

    DS, Apr 11, 2004, in forum: Digital Photography
    Replies:
    1
    Views:
    323
    Lucas Tam
    Apr 11, 2004
  4. .
    Replies:
    1
    Views:
    536
    Robert Baer
    Jun 18, 2004
  5. Giuen
    Replies:
    0
    Views:
    1,150
    Giuen
    Sep 12, 2008
Loading...

Share This Page