Round trip delay to a branch office

[shane.oconnell]

Hi Guys,

Can anyone tell me or point me to a document that specifies what the maximum threshold accepted round trip delay to a branch office when implemeting VOIP phones in the office, so that the voice quality remains high...

I beleive I read somewhere that ideally it should be below 150ms....

Thanks

[William Bell · Accepted solution]

From the SRND:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/8x/netstruc.html#wp1044270

Delay in IP Voice Networks

Recommendation G.114 of the International Telecommunication Union (ITU)  states that the one-way delay in a voice network should be less than or  equal to 150 milliseconds. It is important to keep this in mind when  implementing low-speed WAN links within a network. Topologies,  technologies, and physical distance should be considered for WAN links  so that one-way delay is kept at or below this 150-millisecond  recommendation. Implementing a VoIP network where the one-way delay  exceeds 150 milliseconds introduces issues not only with the quality of  the voice call but also with call setup and media cut-through times  because several call signaling messages need to be exchanged between  each device and the call processing application in order to establish  the call.

HTH.

Regards,
Bill

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[shane.oconnell]

Thank you