cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
7403
Views
10
Helpful
5
Replies
e.hoehn
Beginner

IP-sla udp-jitter / one-way delay no output

Hi *,

i have a question regarding "ip sla udp-jitter".
On some connectins i get an output for the "show ip sla stat" for the _one-way delay_
on other links i don't get an output. The Configuration is always the same and the Probes are running.
NTP is configured but in my opinion the fact weather i get output for the _one-way delay_
or not depends on the ntp root despersion.
Is there a max allowed time differances between the two routes ?

Here one working / one not working output of the same Router but different peers:

Not working::

Latest operation return code: OK

RTT Values:

Number Of RTT: 100RTT Min/Avg/Max: 11/11/13 milliseconds

Latency one-way time:

Number of Latency one-way Samples: 0

Source to Destination Latency one way Min/Avg/Max: 0/0/0 milliseconds

Destination to Source Latency one way Min/Avg/Max: 0/0/0 milliseconds

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

Working:

Latest operation return code: OK

RTT Values:

Number Of RTT: 100RTT Min/Avg/Max: 12/13/14 milliseconds

Latency one-way time:

Number of Latency one-way Samples: 100

Source to Destination Latency one way Min/Avg/Max: 6/7/8 milliseconds

Destination to Source Latency one way Min/Avg/Max: 5/6/7 milliseconds

I hope one of you can help me to find / fix the problem,

Thanks in advance / Emanuel

5 REPLIES 5
khernandezruiz
Beginner

Hi everyone,

I have the same doubt.

I did a ip sla configuration on 1841 and 7206VXR and don't show nothing in one-way delay.

----------------------7206---------------------

-ip sla monitor responder
-ip sla monitor 1
- type jitter dest-ipaddr 10.9.105.14 dest-port 16384 source-ipaddr 10.8.20.102  codec g711alaw
- tos 184
-ip sla monitor schedule 1 start-time now
-ntp peer 10.9.105.14

HOST)#show ip sla sta

Round Trip Time (RTT) for       Index 1
        Latest RTT: 507 milliseconds
Latest operation start time: 10:57:36.619 UTC Sun Oct 10 2010
Latest operation return code: OK
RTT Values:
        Number Of RTT: 1000             RTT Min/Avg/Max: 125/507/846 milliseconds
Latency one-way time:
        Number of Latency one-way Samples: 0
        Source to Destination Latency one way Min/Avg/Max: 0/0/0 milliseconds
        Destination to Source Latency one way Min/Avg/Max: 0/0/0 milliseconds
Jitter Time:
        Number of Jitter Samples: 999
        Source to Destination Jitter Min/Avg/Max: 1/1/6 milliseconds
        Destination to Source Jitter Min/Avg/Max: 1/5/23 milliseconds
Packet Loss Values:
        Loss Source to Destination: 0           Loss Destination to Source: 0
        Out Of Sequence: 0      Tail Drop: 0    Packet Late Arrival: 0
Voice Score Values:
        Calculated Planning Impairment Factor (ICPIF): 17
        Mean Opinion Score (MOS): 3.84
Number of successes: 38
Number of failures: 0
Operation time to live: 1347 sec

-------------------------1841-------------------------------

-ip sla monitor responder
-ip sla monitor 1
- type jitter dest-ipaddr 10.8.20.102 dest-port 16384 source-ipaddr 10.9.105.14 codec g711alaw
- tos 184
-ip sla monitor schedule 1 start-time now
-ntp peer 10.8.20.102

3383)#show ip sla monitor statistic
Round trip time (RTT)   Index 1
        Latest RTT: 614 ms
Latest operation start time: 10:50:50.491 UTC Wed Oct 27 2010
Latest operation return code: OK
RTT Values
        Number Of RTT: 999
        RTT Min/Avg/Max: 347/614/867 ms
Latency one-way time milliseconds
        Number of one-way Samples: 0
        Source to Destination one way Min/Avg/Max: 0/0/0 ms
        Destination to Source one way Min/Avg/Max: 0/0/0 ms
Jitter time milliseconds
        Number of SD Jitter Samples: 997
        Number of DS Jitter Samples: 998
        Source to Destination Jitter Min/Avg/Max: 0/6/19 ms
        Destination to Source Jitter Min/Avg/Max: 0/1/3 ms
Packet Loss Values
        Loss Source to Destination: 1           Loss Destination to Source: 0
        Out Of Sequence: 0      Tail Drop: 0    Packet Late Arrival: 0
Voice Score Values
        Calculated Planning Impairment Factor (ICPIF): 20
MOS score: 3.72
Number of successes: 32
Number of failures: 0
Operation time to live: 1668 sec

ccarring
Cisco Employee

Hi Emanuel,

I think the most likely cause here is that the NTP clocks on *some* of your responders are out of sync by more than 15% (of the latency measure in that packet) compared to the source router.

Enable debug for ip sla trace, and check the log for messages similar to the following:

029474: Aug 11 13:09:29.829 CDT: IPSLA-OPER_TRACE:OPER:1 icmp-jitter STS:65369798, RTD: 65369759, STD: 65369760, RTS: 65369831

The value from STS, RTD, STD and RTS should be in ascending order:    STS < RTD < STD < RTS.

In my example there, the log shows RTD is smaller than STS. Unfortunately, with  icmp-jitter, you can only try to bring Responder back in sync.

If you cannot bring time in sync between 2 devices, then alternatively, you might try to use udp-jitter which allows you to configure clock-tolerance.
Here's an example:

rt1(config-ip-sla)#udp-jitter 2.2.2.2 222

rt1(config-ip-sla-jitter)#clock-tolerance ntp oneway percent ?

  <0-100>  Percent of value measured

Can you use udp-jitter, or configure the clocks to bring them closer to sync?

Curtis

This solution does not work. When i configure clock-tolerance to any number it is still the same result: Number of latency samples = 0. And about the second solution - how am i supposed to bring 2 routers closer to sync when they are connected directly with ethernet cable one is NTP server and second is client?

was this issue solved?

tyoung008
Beginner

If the routers are directly connected, IP SLA could be rounding the values to 0 if the OW delay is < .5 ms.