Conference irocz::common_brouters

925.0. "E1 RAD ASM40-1 clock problems" by BEJVC::JACKWU () Tue Jun 03 1997 13:40

    Hi,
    
    I have a E1 problems of RouteAboutAccess90EW and RAD ASM40-1(not
    ASM40).
    
    These problems seems similar with notes 359.*, 657.* and 657.*.
    
    Please donot ask me to read the above notes. I have studied the
    above notes many times. But those notes cannot solve my problems.
    Please !!!
    
    
    As followings:
    
    +------------+  +-------------+ Leased +-------------+  +------------+
    +RouteAboutEW+--+ RAD ASM40-1 +--------+ RAD ASM40-1 +--+RouteAboutEW+
    +------------+  +-------------+ Line   +-------------+  +------------+
          PPP link  E1 (2M)                E1 (2M)        PPP link
    	        Internal Clock         Receive Clock
    
    According RAD ASM40-1's manaual, we must select InternalClock and
    ReceiveClock
    for two MODEMs because RouteAboutEW cannot provide clock.
    
    If we do the test like above, PPP link is OK at the beginning. But
    there is 
    a lot of packet loss. 
    After 10 minutes(or longer) testing, sometimes the PPP link will down.
    Sometimes the PPP link will not down, but a lot of packet loss.
    
    
    
    With no reason, I change the clock mode as followings:
    
    +------------+  +-------------+ Leased +-------------+  +------------+
    +RouteAboutEW+--+ RAD ASM40-1 +--------+ RAD ASM40-1 +--+RouteAboutEW+
    +------------+  +-------------+ Line   +-------------+  +------------+
          PPP link  E1 (2M)                E1 (2M)        PPP link
    	        Internal Clock         External Clock (!!!!!)
    
    Everything is OK. PPP link is OK. No packets loss.
    
    I cannot explain this. 
    Why ? 
    Can RouteAboutEW provide clock ?
    
    Then I use a Logical Analyzer to check the RouteAboutEW's clock.
    There is a 2M clock provided by RouteAboutEW.
    
    Does RouteAboutEW provice clock ?
    How to configure it ?
    How to disable the clock in order to use external clock ?
    
    
    
    Thanks and Regards.
    
    jackwu from NSIS, ShangHai, PRC.
    

>   Then I use a Logical Analyzer to check the RouteAboutEW's clock.
>   There is a 2M clock provided by RouteAboutEW.
    
    What signal did you check?  TX clock?  I think you will find this is a
    'reflected' version of the RX clock, and not internally generated by
    the router.
    
    What type of cable are you using?