SIP trunking and DSP resources on UC500 systems

firestormnet · ‎03-28-2013

Hi All.

I've come up with some questions and can't find the proper answers for them. I'm wondering if somebody can help me with answers.

1) How can I check how many simultaneous calls can UC500 handle through SIP trunk? How many users can be on the calls at the same time (DDi range is 10 numbers for example)?

I configured UC520 (UC520-16U-K9) for SIP trunk and conferencing, see below:

!

dspfarm profile 2 transcode

description CCA transcoding for SIP Trunk

codec g729abr8

codec g729ar8

codec g711ulaw

maximum sessions 2

associate application SCCP

!

dspfarm profile 1 conference

description DO NOT MODIFY, active CCA conference profile - CCA2.0 codec711

codec g711alaw

codec g711ulaw

maximum conference-participants 16

maximum sessions 2

associate application SCCP

!

For conferencing I can see that max participants only 16. But for SIP trunk only max sessions 2. Does it mean that only 2 calls (can't increase that) can be made simultaneously?

Below is show DSP:

uc520#sh dspfarm all

Dspfarm Profile Configuration

Profile ID = 2, Service = TRANSCODING, Resource ID = 1

Profile Description : CCA transcoding for SIP Trunk

Profile Service Mode : Non Secure

Profile Admin State : UP

Profile Operation State : ACTIVE

Application : SCCP Status : ASSOCIATED

Resource Provider : FLEX_DSPRM Status : UP

Number of Resource Configured : 2

Number of Resource Available : 2

Codec Configuration: num_of_codecs:3

Codec : g729abr8, Maximum Packetization Period : 60

Codec : g729ar8, Maximum Packetization Period : 60

Codec : g711ulaw, Maximum Packetization Period : 30

Dspfarm Profile Configuration

Profile ID = 1, Service = CONFERENCING, Resource ID = 2

Profile Description : DO NOT MODIFY, active CCA conference profile - CCA2.0 codec711

Profile Service Mode : Non Secure

Profile Admin State : UP

Profile Operation State : ACTIVE

Application : SCCP Status : ASSOCIATED

Resource Provider : FLEX_DSPRM Status : UP

Number of Resource Configured : 2

Number of Resource Available : 2

Maximum conference participants : 16

Codec Configuration: num_of_codecs:2

Codec : g711alaw, Maximum Packetization Period : 30 , Transcoder: Not Required

Codec : g711ulaw, Maximum Packetization Period : 30 , Transcoder: Not Required

SLOT DSP VERSION STATUS CHNL USE TYPE RSC_ID BRIDGE_ID PKTS_TXED PKTS_RXED

0 1 28.3.8 UP N/A FREE xcode 1 - - -

0 2 28.3.8 UP N/A FREE conf 2 - - -

Total number of DSPFARM DSP channel(s) 4

2) How can I check the same stuff on UC540 and UC560? Once I configure SIP trunk on them I need to know how many calls (in/out) can be made simultaneously through SIP trunk?

3) If analog fax is connected to UC500, does it use DSP resources when sending/receiving faxes on SIP trunk?

Thanks in advance.

Regards,

firestormnet · ‎03-28-2013

I think I've got an answer: there are only limitations by bandwith and SIP provider (if any).

danplacek · ‎03-28-2013

Codec also matters. If you have to do transcoding from G729 to G711 there will be limits (depends on what you have setup for conferencing too).

-Dan

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firestormnet · ‎04-08-2013

Dan, yes, the transcoding matters as well.

Actually when you configure SIP Trunk using CCA, it gives you "Maximum Number of calls". For example on UC560 there is an option (1-48) to choose from.

Christian Semmler · ‎04-10-2013

Hi,

for the SIP trunks there are no limits from the system. Check this out: https://supportforums.cisco.com/message/3795863#3795863

If you have different voice codecs for your phones and the trunk you need DSP ressources for transcoding.

As I know the UC520 have a PVDM2-64 with 4 DSP chips. You can use the DSP calculator from cisco to find out how many DSPs you need. But keep in mind that conferencing and transcoding can't share a DSP processor.

For example 1 DSP for conferencing and 3 for transcoding.

best regards

Christian

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