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configure GPS sync on ASR9006

Thijs Van Severen
Cisco Employee
Cisco Employee

Hi All,

 

i'm trying to set up timesync on my ASR9006 using GPS signals

i have connected the 1MHz + 1pps signals to the ASR, and i have followed these instructions (found here) to select these signals as clock source

RP/0/RSP0/CPU0:router# configure
RP/0/RSP0/CPU0:router(config)# clock-interface sync 2 location 0/rsp0/cpu0
RP/0/RSP0/CPU0:router(config-clock-if)# port-parameters
RP/0/RSP0/CPU0:router(config-clk-parms)# gps-input tod-format cisco pps-input rs422

i dont get any error message, but other than that i'm pretty much lost ...

there seems to be very little info available on the www about NTP sync using GPS signals

all tips are welcome !

 

grtz

Thijs

42 Replies 42

My configuration is very similar:

frequency synchronization
!
clock-interface sync 2 location 0/RSP0/CPU0
 port-parameters
  gps-input tod-format gprmc pps-input ttl
 !
 frequency synchronization
  selection input
  priority 1
  wait-to-restore 0
  ssm disable
  time-of-day-priority 1
  quality receive exact itu-t option 2 generation 2 PRS
 !

This makes me think the issue is the router decoding the TOD serial string.

I can't find any logs saying it isn't receiving the TOD, but I don't see any change when I unplug the TOD connection.

Thanks,

Stephen

I discussed this issue with our timing guys and they had a few more things to try and verify:

What is the XR software version used?

I think the GPS port will not come up if there is an issue in decoding the ToD. Since the GPS port is up, the issue could be something else.

Is there any mismatch in SSM option configuration (global vs what is configured on the GPS port) ?  DNU is defined for Option 1 and PRS is for option 2.  My suspicion is that the global SSM option is configured to be Option 1.

Please also verify the output of   "show frequency synchronization configuration-errors “.  If there are no errors, we can verify the output of gps-port-dump command.

Bring up the Dao shell by 'run daotmp_client –m’ on RP. Then 'gps-port-dump’ will display more info.

xander

 

Xander,

Thank you for your efforts. It appears you were correct and there was a mismatch on the SSM option.

RP/0/RSP0/CPU0:ROC#show frequency synchronization configuration-errors
Fri Sep 11 04:07:36.546 UTC
Node 0/RSP0/CPU0:
==============
  clock-interface Sync 2 location 0/RSP0/CPU0 frequency synchronization quality
receive exact itu-t option 2 generation 2 PRS
    * The QL that is configured is from a different QL option set than
is configured globally.

I added the option 2 globally and now the "show freq sync clock-interfaces" and "show freq sync selection" commands show this.

  Clock interface Sync2 (Up - GPS)
    Assigned as input for selection
    Wait-to-restore time 0 minutes
    SSM supported
    Input:
      Up
      Effective QL: Opt-II,2/PRS, Priority: 1, Time-of-day Priority 1
      Supports frequency and time-of-day
    Output is disabled
  Next selection points: T0-SEL-B

Selection point: T0-SEL-B (2 inputs, 1 selected)
  Last programmed 00:08:44 ago, and selection made 00:08:38 ago
  Next selection points
    SPA scoped    : None
    Node scoped   : T4-SEL-C CHASSIS-TOD-SEL
    Chassis scoped: LC_TX_SELECT
    Router scoped : None
  Uses frequency selection
  Used for local line interface output
  S  Input                     Last Selection Point         QL  Pri  Status
  == ========================  ========================  =====  ===  ===========
  1  Sync2 [0/RSP0/CPU0]       n/a                         PRS    1  Locked
     Internal0 [0/RSP0/CPU0]   n/a                        ST3E  255  Available

My config now looks like this:

frequency synchronization
 quality itu-t option 2 generation 2
!
clock-interface sync 2 location 0/RSP0/CPU0
 port-parameters
  gps-input tod-format gprmc pps-input ttl
 !
 frequency synchronization
  selection input
  priority 1
  wait-to-restore 0
  ssm disable
  time-of-day-priority 1
  quality receive exact itu-t option 2 generation 2 PRS
 !

I would note that the GPS port can come up without the TOD signal, as physically unplugging the cable left it in the up state.

Thank you very much. I believe my issue is resolved.

Stephen

I may have spoken too soon.

Just to confirm the TOD issue was resolved I turned off the TOD serial string in our clock. Nothing appears to have changed on the router. No logs were generated and the show command outputs above remain unchanged.

We are running v5.3.1.

I receive no output when I issue "gps-port-dump":

RP/0/RSP0/CPU0:ROC#run daotmp_client -m
Fri Sep 11 04:31:13.937 UTC
daotmp>gps-port-dump
daotmp>

The "show freq selection" command even shows Sync2 being used for chassis TOD, but I am certain there is no TOD coming into the router.

Selection point: CHASSIS-TOD-SEL (1 inputs, 1 selected)
  Last programmed 00:28:53 ago, and selection made 00:28:53 ago
  Next selection points
    SPA scoped    : None
    Node scoped   : None
    Chassis scoped: None
    Router scoped : None
  Uses time-of-day selection
  S  Input                     Last Selection Point      Pri  Time  Status
  == ========================  ========================  ===  ====  ===========
  1  Sync2 [0/RSP0/CPU0]       0/RSP0/CPU0 T0-SEL-B 1      1  Yes   Available

What else could I be doing wrong?

Thanks,

Stephen

Stephen Craven
Level 4
Level 4

What kind of connectors do you use to connect to the 1 PPS and 10MHz ports on the RSP?

 

We ordered different genders of SMB connectors and none will fit. It appears like the RSP has the outer diameter of a male SMB with the inside parts of a female SMB.

 

Thanks!

Stephen

hey stephen,

It is said to be "mini coax" of the smb kind, but there are many slight nuances there.

let me find out the cable specifics I had used for a demo setup and I'll let you know if I find a model or a make a picture so you have that.

you would probably hear from me on that either tuesday or wednesday.

xander

Thank you.

I have found other documentation that calls those connections "1.0/2.3 50-ohm RF connector". It appears that 1.0/2.3 is a different connector standard than SMB.

Stephen

hi stephen,

it is definitely not the standard smb. and yeah correct it is a bit confusing. will need to clean that up in the doc.

the picture that you got there is the right model. visually it is the same as I have here too, I am looking for the package to see what the model number is.

xander
 

Xander,

Another question.

If we have two RSP-440s in a chassis, do we need to cable both RSPs (TOD, 1PPS, 10MHz) to the clock, or can the active RSP access the clock inputs on the standby RSP?

Thanks,

Stephen

yes it can take the clock from the other RSP,however it is named differently right.

but then also, if the RSP is working/booted , there is no reason why RSP0 wouldnt be the active, so for redundancy purposes you'd want them connected to both of them or better yet to different chassis possibly and distribute time and freq via 1588 or ntp/synce

cheers

xander

We'd cable RSP0 up to the clock, but I've seen the router switchover to RSP1 for no visible reason with RSP0 still being available.

If this happens you're saying that as long as the RSP cabled to the clock is available in the chassis the active RSP could access it?

(We'll have multiple routers at different sites connected to clocks, so one site's failure wouldn't be a big concern.)

Thanks for the speedy response!

Stephen

hey stephen,

correct the clock interface is represented as 0/rsp0/xxx so it defines the fact where to find that clock, so if it is available and the requirement is that that RSP booted and available (not necessarily active) you can access it.

cheers!

xander

benediktsv
Level 1
Level 1

some pointers I have learned and are quite hard to find 

 

run daotmp_client -m

gps-port-dump

must be run through the console - not via VTY  -else it just returns NULL

 

default baud rate is 4800 baud and seems to be preferred ;)

 

clock-interface sync 2 location 0/RSP0/CPU0
port-parameters
gps-input tod-format gprmc pps-input rs422 baud-rate 9600

 

pps-input TTL = Coax connector on front

pps-input RS422 = pin 1(p)/2(n) on the TOD port

TOD on ASR9k is via TOD port pin 7(p)/8(n)   (reversed pol on the ASR901/903)

 

- Benni

 

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