05-08-2007 10:54 AM - last edited on 03-25-2019 07:35 PM by ciscomoderator
Can anyone help me out the a recommend DSP configuration?
We have a 2811 w/ a PVDM2-16 and a VIC2-4FXO card. I would like to best utilize the DSP resources for MOH, Transfer, and conferencing. We are running CME 4.0(3). We aren't doing any VoIP over the WAN with this site yet but would like to have this ability in the future. I have tried to use the DSP calculator but I really want to know what my options are for the DSP that I have, not vice versa.
Any help would be great!
Solved! Go to Solution.
05-16-2007 09:06 AM
Again, for all intents and purposes, a single 5510 DSP (PVDM2-16) will support *EITHER* 8 transcoding sessions *OR* 8 medium complexity audio calls (G.729a/G.729ab) *OR* 16 low complexity audio calls (G.711).
In my previous post I stated that you pretty much need to assume that a single DSP will only give you 8 channels to work with in most situations. Since it appears that you have 4 channels of hardware analog voice, which will automatically reserve 4 DSP channels, that leaves you with 4 channels for transcoding.
As long as you configure the voice-card 0 for 'codec complexity flex' on your router and expect all hardware analog calls to terminate as G.711, then you *COULD* configure 6 transcoding sessions with a single DSP. The worst case scenerio with this config is if any of the hardware analog calls terminate with a medium complexity codec you will loose 1 or 2 of your transcoding channels during the call(s).
Let me explain it this way, the 5510 DSP when running flex software is broken up into 16 logical channels. Each of the 16 DSP channels can handle a low complexity call (G.711 or fax passthru). A medium complexity call uses the equivalent resources of 2 DSP channels to terminate the call. A transcoding session to or from a medium complexity call (G.729a/G.729ab) from G.711 uses 2 DSP channels.
Have you ever used the DSP calculator on Cisco's web site?
http://www.cisco.com/cgi-bin/Support/DSP/dsp-calc.pl
CLI Information for Optimal results.
To match the DSP Calculator configuration with your router, enter the following commands in configuration mode in your Cisco 2811 router:
!Optimal Results
voice-card 0
codec complexity flex
!Set of Conferencing/Transcoding commands when used with PVDM2-XX DSPs:
sccp local
sccp ccm
sccp
!
sccp ccm group 999
bind interface
associate ccm
associate profile
!
dspfarm profile
maximum sessions 6
associate application SCCP
05-08-2007 06:31 PM
Since you have, PVDM2-16.
You will have only either conference or xcoder&voice termination. not both. you will have to buy more DSPs...
05-09-2007 05:51 AM
OK. Are the resources shared then between transcoding and voice termination? Or do I have to set them up individually? Any recommendations there?
05-09-2007 09:08 AM
DSP can be shared between voice termination and transcoding sessions, but conference DSPs cannot be shared.
Chris
05-09-2007 09:13 AM
Can you provide an example? Is voice termination rolled up into the transcoding piece?
05-09-2007 09:54 AM
Voice termination DSPs get allocated dynamically when you build pri-group for example, here is example of transcoding profile:
HTH, please rate all useful posts!
Chris
05-10-2007 06:41 AM
I am using FXO ports in this particular config:
sccp ccm group 1
bind interface Vlan406
associate ccm 1 priority 1
associate profile 1 register mtp001aa18f8108
!
dspfarm profile 1 transcode
codec g711ulaw
codec g711alaw
codec g729ar8
codec g729abr8
codec gsmfr
maximum sessions 8
associate application SCCP
I am unable to dial out with the maximum sessions set to 8 here. If I lower it I can then dial out on the FXO port through a pots dial peer.
05-10-2007 06:54 AM
What does "sh voice dsp" display?
Chris
05-10-2007 06:56 AM
Configured with max sessions 8:
SE_2811#show voice dsp
DSP DSP DSPWARE CURR BOOT PAK TX/RX
TYPE NUM CH CODEC VERSION STATE STATE RST AI VOICEPORT TS ABORT PACK COUNT
==== === == ======== ======= ===== ======= === == ========= == ===== ============
edsp 001 01 g711ulaw 0.1 IDLE 50/0/1.1
edsp 002 02 g729r8 p 0.1 IDLE 50/0/1.2
edsp 003 01 g711ulaw 0.1 IDLE 50/0/2.1
edsp 004 02 g729r8 p 0.1 IDLE 50/0/2.2
edsp 005 01 g729r8 p 0.1 IDLE 50/0/3.1
edsp 006 02 g729r8 p 0.1 IDLE 50/0/3.2
edsp 007 01 g729r8 p 0.1 IDLE 50/0/18.1
edsp 008 01 g729r8 p 0.1 IDLE 50/0/19.1
----------------------------FLEX VOICE CARD 0 ------------------------------
*DSP VOICE CHANNELS*
CURR STATE : (busy)inuse (b-out)busy out (bpend)busyout pending
LEGEND : (bad)bad (shut)shutdown (dpend)download pending
DSP DSP DSPWARE CURR BOOT PAK TX/RX
TYPE NUM CH CODEC VERSION STATE STATE RST AI VOICEPORT TS ABRT PACK COUNT
===== === == ========= ======= ===== ======= === == ========= == ==== ============
*DSP SIGNALING CHANNELS*
DSP DSP DSPWARE CURR BOOT PAK TX/RX
TYPE NUM CH CODEC VERSION STATE STATE RST AI VOICEPORT TS ABRT PACK COUNT
===== === == ========= ======= ===== ======= === == ========= == ==== ============
C5510 001 01 {flex} 8.4.1 alloc idle 0 0 0/0/0 02 0 46/0
C5510 001 02 {flex} 8.4.1 alloc idle 0 0 0/0/1 06 0 36/0
C5510 001 03 {flex} 8.4.1 alloc idle 0 0 0/0/2 10 0 36/0
C5510 001 04 {flex} 8.4.1 alloc idle 0 0 0/0/3 14 0 36/0
------------------------END OF FLEX VOICE CARD 0 ----------------------------
05-10-2007 07:07 AM
This is also a bit of the config under telephony-service
sdspfarm units 1
sdspfarm transcode sessions 16
sdspfarm tag 1 mtp001aa18f8108
05-12-2007 06:36 AM
Hi Chris,
Are you sure? because SRND does not same the same. May be can share them as you said but 8 will be lost. i hope someone could explain this.
++++++++++++++++++++
1DSP=PVDM2-16=8 calls for voice termination= 8 transcoding sessions, even if we need only 4 or 2
Cisco Unified IP Phones use only the G.729a variants of the G.729 codecs. The default for a new
DSP farm profile is G.729a/G.729ab/G.711u/G.711a. Because a single DSP can provide only one
function at a time, the maximum sessions configured on the profile should be specified in multiples
of 8 to prevent wasted resources.
Reference SRND IP Telephony
+++++++++++++++++++++
Good day
05-15-2007 02:20 PM
The PVDM2-16 is a *SINGLE* DSP with 16 channels of G.711 audio codec or 8 channels of G.729a/G.729ab audio codec or 8x8 G.711 conferencing or 2x8 party mixed mode conferencing or 8 transcoding channels.
Note that in most cases you have either 8 channels of transcoding or 8 channels of medium complexity (G.729a/G.729ab) voice, depending on the analog voice hardware installed in the router. *NOT* both combined. Usually, the voice ports grab DSP channels and they cannot be freed, therefore *ONLY* the leftover DSP channels can be used for transcoding.
In your case, you have a max of 4 channels of transcoding available...
05-16-2007 04:37 AM
Per your calculations, how did you come up with the 4 channels of transcoding? How many channels of G.711, G.729a/G.729ab does that leave me? 12?
05-16-2007 09:06 AM
Again, for all intents and purposes, a single 5510 DSP (PVDM2-16) will support *EITHER* 8 transcoding sessions *OR* 8 medium complexity audio calls (G.729a/G.729ab) *OR* 16 low complexity audio calls (G.711).
In my previous post I stated that you pretty much need to assume that a single DSP will only give you 8 channels to work with in most situations. Since it appears that you have 4 channels of hardware analog voice, which will automatically reserve 4 DSP channels, that leaves you with 4 channels for transcoding.
As long as you configure the voice-card 0 for 'codec complexity flex' on your router and expect all hardware analog calls to terminate as G.711, then you *COULD* configure 6 transcoding sessions with a single DSP. The worst case scenerio with this config is if any of the hardware analog calls terminate with a medium complexity codec you will loose 1 or 2 of your transcoding channels during the call(s).
Let me explain it this way, the 5510 DSP when running flex software is broken up into 16 logical channels. Each of the 16 DSP channels can handle a low complexity call (G.711 or fax passthru). A medium complexity call uses the equivalent resources of 2 DSP channels to terminate the call. A transcoding session to or from a medium complexity call (G.729a/G.729ab) from G.711 uses 2 DSP channels.
Have you ever used the DSP calculator on Cisco's web site?
http://www.cisco.com/cgi-bin/Support/DSP/dsp-calc.pl
CLI Information for Optimal results.
To match the DSP Calculator configuration with your router, enter the following commands in configuration mode in your Cisco 2811 router:
!Optimal Results
voice-card 0
codec complexity flex
!Set of Conferencing/Transcoding commands when used with PVDM2-XX DSPs:
sccp local
sccp ccm
sccp
!
sccp ccm group 999
bind interface
associate ccm
associate profile
!
dspfarm profile
maximum sessions 6
associate application SCCP
05-18-2007 11:48 AM
What part do the following statements play:
sdspfarm units 1
sdspfarm transcode sessions 16
sdspfarm tag 1 mtp001aa18f8108
in relation to what you have above? Do I still need these statements?
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