[cisco-nas] Slips

Aaron Leonard Aaron at cisco.com
Wed Oct 10 14:09:48 EDT 2012


I suppose it is possible that a DACS could introduce enough jitter into 
the signal to keep the other system from deriving clock from the line.  
This is not a problem in the general case though.

------------------------------------------------------------------------

On 10/9/2012 9:31 PM, jfmays at launchpad.win.net (Joe Mays) wrote:
> It has been suggested that if those circuits go through a DAX, the 
> clocking signal may not be making it to the other system.
>
>     ----- Original Message -----
>     *From:* Aaron Leonard <mailto:Aaron at cisco.com>
>     *To:* Joseph Mays <mailto:mays at win.net>
>     *Cc:* cisco-nas at puck.nether.net <mailto:cisco-nas at puck.nether.net>
>     *Sent:* Tuesday, October 09, 2012 7:00 PM
>     *Subject:* Re: [cisco-nas] Slips
>
>     The 5400 has only one clocking domain.  So, if you are getting
>     clock from slot 6 port 0, then this is the time source for the
>     whole TDM bus.  So, all other T1s on the 5400 will be synchronized
>     to that source, and anything that takes clock from those T1s
>     should be synchronized.
>
>     http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a008014f8a6.shtml
>
>     That's why I suspect that the system on the other side of T1 6/1
>     is not actually taking clock from the line.  Maybe it's free
>     running or maybe it's taking clock from something else.
>
>     Aaron
>
>     ------------------------------------------------------------------------
>
>     On 10/9/2012 2:46 PM, mays at win.net (Joseph Mays) wrote:
>>     I would like to change port 6/1 to clocking internal, but I can't
>>     find any way change the clocking on an individual t1 port
>>     controller to internal. Am I missing something?
>>
>>         ----- Original Message -----
>>         *From:* Joseph Mays <mailto:mays at win.net>
>>         *To:* Aaron Leonard <mailto:Aaron at cisco.com>
>>         *Cc:* cisco-nas at puck.nether.net
>>         <mailto:cisco-nas at puck.nether.net>
>>         *Sent:* Tuesday, October 09, 2012 4:48 PM
>>         *Subject:* Re: [cisco-nas] Slips
>>
>>         Thank you for your response.
>>         Show tdm clocks shows the AS5400 is using the circuit in port
>>         6/0 for primary clocking.
>>         Primary Clock:
>>         --------------
>>         System primary is slot 6 port 0 of priority 1
>>         TDM Bus Master Clock Generator State = NORMAL
>>         Backup clocks for primary:
>>         Source  Slot  Port  DS3-Port  Priority      Status State
>>         -------------------------------------------------------------
>>         Trunk   1     1       YES       2            Good Configured
>>         Trunk   1     2       YES       3            Good Configured
>>         Trunk   1     3       YES       4            Good Configured
>>         Trunk   1     4       YES       5            Good Configured
>>         Trunk   1     5       YES       6            Good Configured
>>         Trunk   6     1       NO        213          Good Default
>>         Trunk   1     28      YES       202          Good Default
>>         Trunk   1     27      YES       203          Good Default
>>         Trunk cards controllers clock health information
>>         ------------------------------------------------
>>               CT3         2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
>>         Slot  Port  Type  8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7
>>         6 5 4 3 2 1
>>         1     0      T3   G G G B B G G B B G B G B B B B B B B B B B
>>         B G G G G G
>>         We had considered the possibility that the problem might be
>>         coming from the mux that everything was passing through. I
>>         rewired the pinouts from telco in order to connect them
>>         directly to a t1 port on the AS5400 (Controller 6/1), rather
>>         than passing them through the mux and coming across a channel
>>         on the t3. It works, but the slips are exactly the same.
>>         ArmoryPl-AS5400#show controller t1 6/1
>>         T1 6/1 is up.
>>           Applique type is Channelized T1
>>           Cablelength is long gain36 0db
>>           Description: Leonard Brush MUX Bypass
>>           No alarms detected.
>>           alarm-trigger is not set
>>           Version info of slot 6:  HW: 768, PLD Rev: 1
>>           Framer Version: 0x8
>>         Manufacture Cookie Info:
>>          EEPROM Type 0x0001, EEPROM Version 0x01, Board ID 0x02,
>>          Board Hardware Version 3.0, Item Number 73-3996-03,
>>          Board Revision A0, Serial Number JAB044106K3,
>>          PLD/ISP Version <unset>,  Manufacture Date 11-Oct-2000.
>>           Framing is ESF, Line Code is B8ZS, Clock Source is Line.
>>           Data in current interval (638 seconds elapsed):
>>              0 Line Code Violations, 0 Path Code Violations
>>              54 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0
>>         Degraded Mins
>>              54 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs,
>>         0 Unavail Secs
>>         Right next to it is the trunking circut plugged into 6/0, it
>>         runs fine, no slips. I would like to change 6/1 to internal
>>         clocking, btw, so that it should be following the clock that
>>         is being derived on 6/0, but can't find anyway to change that
>>         on the t1 ports. So as it stands right now, both 6/1 and the
>>         customer router on the other end of that t1 are set to
>>         clock-source line, with no mux between them. And getting slips.
>>         ----- Original Message -----
>>         From: "Aaron Leonard" <Aaron at cisco.com <mailto:Aaron at cisco.com>>
>>         To: "Joseph Mays" <jfmays at launchpad.win.net
>>         <mailto:jfmays at launchpad.win.net>>
>>         Cc: <cisco-nas at puck.nether.net
>>         <mailto:cisco-nas at puck.nether.net>>
>>         Sent: Tuesday, October 09, 2012 3:21 PM
>>         Subject: Re: [cisco-nas] Slips
>>
>>         > Joe,
>>         >
>>         > Sounds like, conceptually, you've set things up right.  I
>>         would
>>         > doublecheck on the customer routers to make sure that they
>>         really are
>>         > taking clock from the right T1 line.
>>         >
>>         > On the 5400, you should be using "tdm clock priority" to
>>         set the clock
>>         > source, and "show tdm clocks" to validate the clocking.
>>         >
>>         http://www.cisco.com/en/US/docs/ios/12_3/dial/command/reference/dia_s6g.html#wp1140246
>>         >
>>         > Aaron
>>         >
>>         > ----
>>         >
>>         > On 10/9/2012 8:43 AM, jfmays at launchpad.win.net
>>         <mailto:jfmays at launchpad.win.net>(Joseph Mays) wrote:
>>         >> It occurs to me that there is an assumption built into
>>         this that is
>>         >> unproven. Does setting the AS5400 to internal clocking on
>>         the T3 cause it to
>>         >> provide clocking for the T1's on the T3? We have assumed
>>         that it does. If
>>         >> not, how do we tell it to provide an outgoing clock signal
>>         for the T1's on
>>         >> the T3?
>>         >>
>>         >> ----- Original Message -----
>>         >> From: "Joe Mays" <mays at win.net <mailto:mays at win.net>>
>>         >> To: "cisco-nsp" <cisco-nsp at puck.nether.net
>>         <mailto:cisco-nsp at puck.nether.net>>;
>>         <cisco-nas at puck.nether.net <mailto:cisco-nas at puck.nether.net>>
>>         >> Sent: Tuesday, October 09, 2012 12:57 AM
>>         >> Subject: [cisco-nas] Slips
>>         >>
>>         >>
>>         >>> We have an AS5400 that we are using to provide PRI's to
>>         customers. It has
>>         >>> the following circuits coming into it from the Telco (AT&T).
>>         >>>
>>         >>> 5 Trunking circuits that come across T1 ties into a t3
>>         mux, and then are
>>         >>> then delivered to a T3 port on the AS5400. ! trunking
>>         circuit that is
>>         >>> connected into a T1 card on the AS5400. Several circuits
>>         to customers that
>>         >>> are delivered out of the T3 through the mux to T1 tie
>>         pairs through AT&T,
>>         >>> and some of which go through HDSL T1's that we provide.
>>         >>>
>>         >>> We have clocking set up thusly. The T1 port that has the
>>         trunk line in it
>>         >>> (Serial6/0) is set to clock source line, to get clocking
>>         from AT&T.
>>         >>> The TDM clock priority on AS5400 is set to Serial6/0.
>>         >>> The T3 that has all the other T1's is set to clock source
>>         internal, on the
>>         >>> assumption that the internal clock on the AS5400 should
>>         now be
>>         >>> synchronizing to the trunk line coming in on 6/0. So all
>>         the T1 channels
>>         >>> on the T3 should be following the Cisco clock.
>>         >>> The mux is set to clocking is set on the t3 to clock
>>         source line, to get
>>         >>> clocking from the T3 coming from the AS5400.
>>         >>> The customers at the end are all set to clock source line.
>>         >>>
>>         >>> None of the trunks is having slips, but several of the
>>         AT&T customers are
>>         >>> showing a slip every 10 seconds or so. The clocking chain
>>         we have set up
>>         >>> seems logical to me. Is there something I'm missing? Why
>>         would the
>>         >>> customers be having slips.
>>         >>>
>>         >>> We asked AT&T to monitor one of the lines that we are
>>         seeing slips on.
>>         >>> They watched it for a bit and said no slips are
>>         occurring, though I am
>>         >>> seeing them both on the AS5400 and on the Customer
>>         router. They are
>>         >>> performing a more indepth test now.
>>         >>>
>>         >>>
>>         >>> _______________________________________________
>>         >>> cisco-nas mailing list
>>         >>> cisco-nas at puck.nether.net <mailto:cisco-nas at puck.nether.net>
>>         >>> https://puck.nether.net/mailman/listinfo/cisco-nas
>>         >>
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