VoIP and RTP
Does RTP do sequencing??
If yes, i assume this means that VoIP packets can arrive out of order?
If yes, i assume this means that VoIP packets can arrive out of order?
CCIE# 38186
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Comments
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Met44 Member Posts: 194Yes, RTP does sequencing.
VoIP clients usually have a jitter buffer feature. Softphones I have seen are usually around 20ms. Within that 20ms buffer, RTP re-orders voice packets (if necessary) and spaces them out so we hear a steady stream of voice. -
mzinz Member Posts: 328What does Cisco consider the highest amount of allowable latency between two VoIP hosts?_______LAB________
2x 2950
2x 3550
2x 2650XM
2x 3640
1x 2801 -
networker050184 Mod Posts: 11,962 ModThe recommendation is that delay should not exceed 150ms one way (from mouth to ear). I have ran VoIP networks that were upwards of 300ms delay one way with success though.An expert is a man who has made all the mistakes which can be made.
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rakem Member Posts: 800networker050184 wrote: »The recommendation is that delay should not exceed 150ms one way (from mouth to ear). I have ran VoIP networks that were upwards of 300ms delay one way with success though.
Yea Cisco say 150 but i have read other places that say 250. I would say that getting higher than 300 would definitely start to cause some issues.CCIE# 38186
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AlanJames Member Posts: 230rtp = real time. The end user needs to receive them in order, so it has to be time stamped :PWhat does Cisco consider the highest amount of allowable latency between two VoIP hosts?
If you have call manager across sites, it needs to be 40ms round trip delay for successful coms between servers. -
kryolla Member Posts: 785I was just in a class about setting up a Satellite link to replace our backhaul in case it goes down and this would introduce a delay of 250ms one-way which they said was acceptable but needed an echo can. Did anybody else have to put an echo can for the increase in delay? THanksStudying for CCIE and drinking Home Brew
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rakem Member Posts: 800I was just in a class about setting up a Satellite link to replace our backhaul in case it goes down and this would introduce a delay of 250ms one-way which they said was acceptable but needed an echo can. Did anybody else have to put an echo can for the increase in delay? THanks
wtf is an echo can?CCIE# 38186
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shodown Member Posts: 2,271rtp = real time. The end user needs to receive them in order, so it has to be time stamped :P
250ms
If you have call manager across sites, it needs to be 40ms round trip delay for successful coms between servers.
Only if they are in the same cluster. You can have trunks to other sites that have there own cluster and this problem goes away.Currently Reading
CUCM SRND 9x/10, UCCX SRND 10x, QOS SRND, SIP Trunking Guide, anything contact center related -
networker050184 Mod Posts: 11,962 Modwtf is an echo can?
Echo canceler, which basically removes echo from voice calls by removing redundant signals.
If you are using Cisco the echo cancellation will take place in the DSPs. I have never had to use it on satellite links, your millage may vary.An expert is a man who has made all the mistakes which can be made.