2621xm with nm-16a and LOW speeds

Discussion in 'Cisco' started by A. Andrews, Jan 15, 2004.

  1. A. Andrews

    A. Andrews Guest

    I have a TAC opened but I was wondering if anyone out there has any
    ideas....

    We are installing 2621XMs with nm-16a in some and nm-4a/s in others.
    Connected to these serial modules are asynchronous devices working at
    VERY low baud rates (as low at 150 baud).
    The problem that we are finding is that the serial data is being
    fragmented. Where the baud rate is so slow the router is sending the
    information off before it has all arrived.
    Ideas?
     
    A. Andrews, Jan 15, 2004
    #1
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  2. Hi

    If it is IP you are using then you could try this. (Only try - no
    guarentees! :) )

    What it does is sets the 'Don't Fragment' bit in an IP header incoming
    on serial1 so routers can't fragment the packet.

    interface Serial1
    ip policy route-map set-df
    !
    route-map set-df permit 10
    match ip address 1
    set ip df 1

    Simon
     
    Simon Tibbitts, Jan 15, 2004
    #2
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  3. ~ I have a TAC opened but I was wondering if anyone out there has any
    ~ ideas....
    ~
    ~ We are installing 2621XMs with nm-16a in some and nm-4a/s in others.
    ~ Connected to these serial modules are asynchronous devices working at
    ~ VERY low baud rates (as low at 150 baud).
    ~ The problem that we are finding is that the serial data is being
    ~ fragmented. Where the baud rate is so slow the router is sending the
    ~ information off before it has all arrived.
    ~ Ideas?

    Perhaps something like this could work ...

    For a pretty generic dispatch-on-pause, you'd use something like:

    state-machine pauses 0 0 255 0 delay
    line 1 16
    dispatch-machine pauses

    It reads as "in state 0, have all characters (0-255) transition (back) to
    state 0, after starting the "transmit on pause" timer"

    Aaron
     
    Aaron Leonard, Jan 16, 2004
    #3
  4. A. Andrews

    A. Andrews Guest

    Thanks guys Ill do some reading on that!
     
    A. Andrews, Jan 16, 2004
    #4
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