Cisco PVDM2 and PVDM3 DSP Credit/MIPs Allocation.

Ayodeji Okanlawon · ‎01-10-2013

Introduction</A> </H1>

I have over the years heard of cisco dsps using MIPs/credits but I never quite understood how they work. What I know like many of you is that I can tell how many number of channels a dsp can support based on the PVDM part number.<o:p></o:p>

e.g PVDM2-32 can support 32 channels; PVDM3-64 can support 64 channels and so on. In actual fact these computations depends largely on the dsp complexity mode.<o:p></o:p>

e.g A PVDM2-32 can support 32 channels or 32 G711 calls, using the default flex dsp mode. If the dsp complexity is changed to high, these values are significantly altered. <o:p></o:p>

Example: A PVDM2-32 that supports 32 channels in flex mode, will only support 16 channels in when the dsp complexity is changed to high. Mysteries abound in cisco world! Our job often times is to solve these riddles.<o:p></o:p>

So what is the magic behind all this mathematics? I hope you like maths! We will be doing a lot of it here! I have always wanted to know how these computations work and in here I attempt to share my findings.<o:p></o:p>

You may want to ask why bother knowing these details when we have the cisco dsp calculator. Here are my thoughts on this

· It’s similar to asking why do you need to know SQL to query/update CUCM database when we already have the CUCM admin page to do that. The answer is obvious; something’s can’t be done from the ccm admin page.<o:p></o:p>

· From a design point dsp calculator is very effective and should be used, however when things break then this direct knowledge becomes essential<o:p></o:p>

· As far as I know, the dsp calculator does not take into consideration dsp pooling. Hence you could end up with an over the size resources or “not so cost effective solution” when you could have used existing resources. <o:p></o:p>

<o:p> </o:p>

<H1 style="MARGIN: 24pt 0cm 0pt" mcestyle="margin: 24pt 0cm 0pt;">DSP CREDITS</A><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></H1>

Before we begin, it’s important to establish this fact. Each PVDM is equipped with a number of DSPs or cores. The higher the number of DSP, the greater the processing power of that PVDM. That obviously is not rocket science. But what is is this: Each dsp/cores within a Cisco PVDM is allocated a fixed amount of what is called “credits”. This is the “biggy!” The power of a DSP depends on the amount of credit that is allocated to it.<o:p></o:p>

PVDM3 and PVDM2 DSP modules use a credit-based system. Each module is assigned a fixed number of "credits" that represent a measure of its capacity to process media streams. Each media operation, such as voice termination, transcoding, and so forth, is assigned a cost in terms of credits. As DSP resources are allocated for a media processing function, its cost value is subtracted from the available credits. A DSP module runs out of capacity when the available credits run out and are no longer sufficient for the requested operation<o:p></o:p>

<o:p> </o:p>

The table below shows the relations between PVDM, DSP and Credits allocated to each dsp

PVDM<o:p></o:p></TD>

Number of DSP<o:p></o:p></TD>

Credits/DSP or Credits/Core<o:p></o:p></TD></TR>

PVDM3-16<o:p></o:p></TD>

1<o:p></o:p></TD>

240<o:p></o:p></TD></TR>

PVDM3-32<o:p></o:p></TD>

1<o:p></o:p></TD>

480<o:p></o:p></TD></TR>

PVDM3-64<o:p></o:p></TD>

2<o:p></o:p></TD>

480<o:p></o:p></TD></TR>

PVDM3-128<o:p></o:p></TD>

3<o:p></o:p></TD>

480<o:p></o:p></TD></TR>

PVDM3-192<o:p></o:p></TD>

5<o:p></o:p></TD>

480,645 (read PVDM3-192 section)<o:p></o:p></TD></TR>

PVDM3-256<o:p></o:p></TD>

6<o:p></o:p></TD>

645<o:p></o:p></TD></TR>

PVDM2-8<o:p></o:p></TD>

1/2<o:p></o:p></TD>

120<o:p></o:p></TD></TR>

PVDM2-16<o:p></o:p></TD>

1<o:p></o:p></TD>

240<o:p></o:p></TD></TR>

PVDM2-32<o:p></o:p></TD>

2<o:p></o:p></TD>

240<o:p></o:p></TD></TR>

PVDM2-48<o:p></o:p></TD>

3<o:p></o:p></TD>

240<o:p></o:p></TD></TR>

PVDM2-64<o:p></o:p></TD>

4<o:p></o:p></TD>

240<o:p></o:p></TD></TR></TBODY></TABLE>

<o:p> </o:p>

<H2 style="LINE-HEIGHT: normal; MARGIN: 10pt 0cm 0pt" mcestyle="line-height: normal; margin: 10pt 0cm 0pt;">How to Determine Credits Allocated to A DSP</A><o:p></o:p></H2>

<o:p> </o:p>

<H2 style="MARGIN: 10pt 0cm 0pt" mcestyle="margin: 10pt 0cm 0pt;">PVDM3-Credits</A><o:p></o:p></H2>

The obvious question is this, how do we know the allocated Credit to a particular DSP. This is very important as you can see that the allocated credit to each DSP vary depending on what PVDM it is on. The answer is in two folds<o:p></o:p>

1. The popular and most useful command showing dsp related information<o:p></o:p>

“Show voice dsp group all”<o:p></o:p>

Please refer to this document to understand the output of this command in detail.<o:p></o:p>

https://supportforums.cisco.com/docs/DOC-29151<o:p></o:p>

LABUK-02S-ERT01#Show voice dsp group all (for a PVDM3-128)<o:p></o:p>

<SPAN style="FONT-FAMILY: Wingdings; COLOR: #333333; FONT-SIZE: 10pt; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-language: EN-GB; mso-ansi-language: EN; mso-bidi-font-size: 9.0pt" lang=EN mcestyle="font-family: Wingdings; color: #333333; font-size: 10pt; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-language: EN-GB; mso-ansi-language: EN; mso-bidi-font-size: 9.0pt;">§ <SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;">DSP groups on slot 0:
dsp 1:
State: UP, firmware: 28.3.3
Max signal/voice channel: 43/43
Max credits: 645

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Transcoding channels allocated: 6<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Group: FLEX_GROUP_VOICE, complexity: FLEX

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Signaling channels allocated: 30

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;">dsp 2:
State: UP, firmware: 28.3.3
Max signal/voice channel: 43/43
Max credits: 645

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Transcoding channels allocated: 14<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Group: FLEX_GROUP_VOICE, complexity: FLEX

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> State: UP, firmware: 28.3.3<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> <SPAN style="BORDER-BOTTOM: windowtext 1pt; BORDER-LEFT: windowtext 1pt; PADDING-BOTTOM: 0cm; PADDING-LEFT: 0cm; PADDING-RIGHT: 0cm; BORDER-TOP: windowtext 1pt; BORDER-RIGHT: windowtext 1pt; PADDING-TOP: 0cm; mso-border-alt: none windowtext 0cm" mcestyle="mso-border-alt: none windowtext 0cm; border: windowtext 1pt; padding: 0cm;">Max signal/voice channel: 42/43<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Max credits: 645<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;">, Voice credits: 645, Video credits: 0<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> num_of_sig_chnls_allocated: 18<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Transcoding channels allocated: 0<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Group: FLEX_GROUP_VOICE, complexity: FLEX<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Shared credits: 276, reserved credits: 0<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Signaling channels allocated: 18<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Voice channels allocated: 0<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Credits used (rounded-up): 0<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Group: FLEX_GROUP_CONF, complexity: CONFERENCE<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Shared credits: 0, reserved credits: 369<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Codec: CONF_G729, maximum participants: 8<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Sessions per dsp: 7<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> Device idx: 0<o:p></o:p>

<o:p> </o:p>

From the output of the above command we can see that each core/dsp in a PVDM3-128 has a fixed credit of 645. This information is obtained from the “Max credits:645” Line<o:p></o:p>

2. The second way is to use another not so popular command on the IOS: “show voice dsp capabilities slot x dsp y”, where x=PVDM slot and y=dsp number on PVDM<o:p></o:p>

#show voice dsp capabilities slot 0 dsp 1 (PVDM3-128)<o:p></o:p>

DSP Type: SP2600 -43<o:p></o:p>

Card 0 DSP id 1 Capabilities:<o:p></o:p>

Credits 645 , G711Credits 15, HC Credits 32, MC Credits 20,<o:p></o:p>

FC Channel 43, HC Channel 20, MC Channel 32,<o:p></o:p>

Conference 8-party credits:<o:p></o:p>

G711 40 , G729 92 , G722 92 , ILBC 129<o:p></o:p>

<o:p> </o:p>

This command showed us the maximum credit for this dsp, which we can see is consistent with the output of the show voice dsp group all command.<o:p></o:p>

Let’s look at another example: PVDM3-64<o:p></o:p>

LABUK-01S-ERT01#show voice dsp group allDSP groups on slot 0:dsp 1: Max credits: 480----

We see that 480 credit is allocated to each dsp in a PVDM3-64

dsp 2: Max credits: 480

Now we see that the credit on each dsp varies depending on the PVDM it resides in. <o:p></o:p>

<H2 style="MARGIN: 10pt 0cm 0pt" mcestyle="margin: 10pt 0cm 0pt;">PVDM2-CreditsOn the PVDM2s, the credit allocated to each dsp in the PVDMs is 240 except for the PVDM2-8 which has 120 credits.

#show voice dsp group all (PVDM2-64, showing only the first dsp)dsp 1: State: UP, firmware: 4.4.20 Max signal/voice channel: 16/16 Max credits: 240 Group: FLEX_GROUP_VOICE, complexity: FLEX Shared credits: 180, reserved credits: 0 Signaling channels allocated: 16 Voice channels allocated: 3 Credits used: 60 Voice channels: Ch02: voice port: 0/0/0:23.23, codec: g711ulaw, credits allocated: 30 Ch03: voice port: 0/0/0:23.20, codec: g711ulaw, credits allocated: 15 Ch04: voice port: 0/0/0:23.19, codec: g711ulaw, credits allocated: 15 Group: FLEX_GROUP_XCODE, complexity: MEDIUM Shared credits: 0, reserved credits: 0 Transcoding channels allocated: 0 Credits used: 0 </o:p>

The PVDM3-192 has a total of 5 dsps in it. In the table above you can see that the number of credits is 480,645. The reason for this is that this PVDM is built as follows:<o:p></o:p>

<o:p> </o:p>

PVDM3-128 + PVDM3-64. <o:p></o:p>

<o:p> </o:p>

This PVDM is a combination of PVDM3-128 and PVDM3-64, hence since dsp of PVDM3-128 has 645 credits and each dsp of the PVDM3-64 has 480 credits<o:p></o:p>

<H1 style="MARGIN: 24pt 0cm 0pt" mcestyle="margin: 24pt 0cm 0pt;">DSP Channel Calculations/Voice Termination</A><o:p></o:p></H1>

<o:p> </o:p>

<o:p> </o:p>

Now that we understand and know how many credits each dsp has, we can then go on to attempt to understand how each dsp and corresponding PVDM support a “X” amount of voice channels.<o:p></o:p>

<o:p> </o:p>

The total amount of voice channels a dsp can support is dependent on two factors:<o:p></o:p>

<o:p> </o:p>

1. Maximum Credits<o:p></o:p>

2. DSP complexity mode.<o:p></o:p>

<o:p> </o:p>

To understand more about DSP complexity mode, please refer to this document:<o:p></o:p>

<o:p> </o:p>

<A href="http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/media.html#wp1045532" mcehref="http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/media.html#wp1045532">http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/media.html#wp1045532</A><o:p></o:p>

<o:p> </o:p>

The amount of credit consumed by a single call or channel depends on the dsp complexity mode and on the dsp itself. The credits used for calls vary from DSP to DSP on the PVDM3. So question is how can we find out?<o:p></o:p>

The powerful command “show voice dsp capabilities” is the answer.<o:p></o:p>

Example1 (DSP1 on a PVDM3-128)<o:p></o:p>

LABUK-01-ERT01#sh voice dsp capabilities slot 0 dsp 1<o:p></o:p>

DSP Type: SP2600 -43<o:p></o:p>

Card 0 DSP id 1 Capabilities:<o:p></o:p>

Credits 645 , G711Credits 15, HC Credits 32, MC Credits 20,<o:p></o:p>

FC Channel 43, HC Channel 20, MC Channel 32,<o:p></o:p>

Conference 8-party credits:<o:p></o:p>

G711 40 , G729 92 , G722 92 , ILBC 129<o:p></o:p>

Example2 (DSP1 on a PVDM3-64)<o:p></o:p>

<o:p> </o:p>

LABUK-0115S-ERT01#sh voice dsp capabilities slot 0 dsp 1<o:p></o:p>

DSP Type: SP2600 -32<o:p></o:p>

Card 0 DSP id 1 Capabilities:<o:p></o:p>

Credits 480 , G711Credits 15, HC Credits 34, MC Credits 22<o:p></o:p>

FC Channel 32, HC Channel 14, MC Channel 21,<o:p></o:p>

Conference 8-party credits:<o:p></o:p>

G711 36 , G729 96 , G722 96 , ILBC 120<o:p></o:p>

<o:p>

PVDM<o:p></o:p></TD>

PVDM3-16<o:p></o:p></TD>

PVDM3-64<o:p></o:p></TD>

PVDM3-128<o:p></o:p></TD></TR>

G711 credits<o:p></o:p></TD>

15<o:p></o:p></TD>

15<o:p></o:p></TD>

15<o:p></o:p></TD></TR>

HC Credits<o:p></o:p></TD>

24<o:p></o:p></TD>

34<o:p></o:p></TD>

32<o:p></o:p></TD></TR>

MC Credits<o:p></o:p></TD>

20<o:p></o:p></TD>

22<o:p></o:p></TD>

20<o:p></o:p></TD></TR></TBODY></TABLE>

<o:p> </o:p>

<o:p> </o:p>

NB: MIPS is the same as credits<o:p></o:p>

<o:p> </o:p>

PVDM2-8 Signaling

-Each Pri slots also count for 1 channel<o:p></o:p>

<o:p> </o:p>

<H2 style="MARGIN: 10pt 0cm 0pt" mcestyle="margin: 10pt 0cm 0pt;">DSP Channel Allocation Example</A><o:p></o:p></H2>

So now that we have established these facts let’s look at an example.<o:p></o:p>

<o:p> </o:p>

How many channels does a PVDM3-128 support in flex mode (uses G711 for analysis) and in High complexity mode (HC)<o:p></o:p>

<o:p> </o:p>

<o:p> </o:p>

Max credit/dsp =645. G711 credit =15, hence 645/15= 43.<o:p></o:p>

So each dsp will support 43 channels/voice calls. However we know that this PVDM has 3 dsps in it, hence if we multiply 43*3=129 channels. So that’s not right because it’s a PVDM3-128. The way this is then done is this.<o:p></o:p>

<o:p> </o:p>

Dsp1=43, dsp2=43, dsp3-42 channels, making a total of 128 channels.<o:p></o:p>

<o:p> </o:p>

This is what we see from the output of the show voice dsp group all command for the dsp3<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> State: UP, firmware: 28.3.3<o:p></o:p>

<SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #333333; FONT-SIZE: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN" lang=EN mcestyle="font-family: 'Arial','sans-serif'; color: #333333; font-size: 9pt; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-GB; mso-ansi-language: EN;"> <SPAN style="BORDER-BOTTOM: windowtext 1pt; BORDER-LEFT: windowtext 1pt; PADDING-BOTTOM: 0cm; PADDING-LEFT: 0cm; PADDING-RIGHT: 0cm; BORDER-TOP: windowtext 1pt; BORDER-RIGHT: windowtext 1pt; PADDING-TOP: 0cm; mso-border-alt: none windowtext 0cm" mcestyle="mso-border-alt: none windowtext 0cm; border: windowtext 1pt; padding: 0cm;">Max signal/voice channel: 42/43----

Max signal=42 out of a possible 43<o:p></o:p>