Jitter

[Cisco Freak]

Hi Experts,

I am trying to understand what Jitter is and how to measure jitter in network. I have setup an ip sla to measure jitter between two routers. Can you please help me understand this result?

R3#sh ip sla statistics 4
IPSLAs Latest Operation Statistics

IPSLA operation id: 4
 Latest RTT: 16 milliseconds
Latest operation start time: 15:08:46 UTC Mon May 22 2017
Latest operation return code: OK

---- Path Jitter Statistics ----

Hop IP 13.1.1.1:
Round Trip Time milliseconds:
 Latest RTT: 16 ms
 Number of RTT: 10
 RTT Min/Avg/Max: 8/16/40 ms
Jitter time milliseconds:
 Number of jitter: 8
 Jitter Min/Avg/Max: 4/14/32 ms
Packet Values:
 Packet Loss (Timeouts): 0
 Out of Sequence: 0
 Discarded Samples: 0
Operation time to live: Forever


R3#

[Philip D'Ath]

Jitter is the variations in latency,

If the latency was 10ms, and then on the next sample it was 12ms, then the jitter would be 2ms.

[Cisco Freak]

Thanks Philip. So this output means there is an average of 14ms between packets? 

And the highest jitter was  32ms between nth and (n+1)th packet.

Jitter time milliseconds:
 Number of jitter: 8
 Jitter Min/Avg/Max: 4/14/32 ms

[Joseph W. Doherty]

See the section "Packet jitter in computer networks" in https://en.wikipedia.org/wiki/Jitter and its reference to https://en.wikipedia.org/wiki/Packet_delay_variation.