2 Office VOIP design, and PVDM usage

[Ahmed Zein]

Dear colleagues,

i have 2 , A and B sites, with same spec's "number of users 16 with IP phones, and just VOIP needed , both will connected via Internet using a FW then IPsec to other branches",

for VOIP solution

A:will call PSTN via 4 analog lines, so i need 4 FXO

B:will call PSTN via VOIP provider so no FXO needed

each branch will call other branches using VOIP h323 trunks

my questions are,

1- PVDM needed?? for both sites?? why PVDM needed??

2-and if both sites will not call PSTN, directly, i.e if i used send landlines calls from the branch to my central office, i.e if i didnt use analog line nor VOIP provider to contact PSTN, IS PVDM NEEDED IN THIS CASE??

your help is appreciated

thanks

[Adrian Saavedra · Accepted solution]

Hi,

You'll need PVDM in sites where FXO cards will be installed. PVDM will be used for voice termination (one leg on TDM interface and the second leg on VoIP).

If you don't need voice cards for PSTN access, you don't need PVDM (unless you need hardware media resources such as transcoding, mtp or conference bridges).

Hope it helps, please rate if it does.

Kind regards,

- Adrian.

[Ahmed Zein]

thanks man for your help

(A)so i need PVDM in cases like

1-there is connection to PSTN via FXO

2-there is connection to PSTN via PRI, or ISDN "i.e digital"

right?

(B)if the connection to PSTN run via a VOIP provider no need for PVDM?

(C)for H/W media resources:

if no PVDM i cant make conference??

(D)when i need to use transcoding? please describe with example.

your reply will be very helpfull to me, thanks in advance

[Adrian Saavedra · Accepted solution]

Hello,

A) Yes, PVDM is mandatory when you're connecting to the PSTN with voice cards.

B) No.

C) If you're using CallManager / CME software conference bridge, you can make conferences only in G.711 (you don't need PVDM here). If you need, for example, conferences using G.711 and G.729 then you need a hardware conference bridge (using PVDM) and registering it to the CM / CME.

D) A transcoder takes the stream of one codec and transcodes (converts) it from one compression type to another compression type. For example, it could take a stream from a G.711 codec and transcode (convert) it in real time to a G.729 stream. CM / CME invokes a transcoder on behalf of endpoint devices when the two devices use different voice codecs and would normally not be able to communicate. When inserted into a call, the transcoder converts the data streams between the two incompatible codecs to enable communications between them.The transcoder remains invisible to either the user or the endpoints that are involved in a call. For example, Cisco Unity Express supports only G.711. When you make a call using G.729 and you need to leave a voicemail, then you need to insert a transcoder in order to communicate with Unity Express.

Hope it helps, please rate if it does.

- Adrian.

[Ahmed Zein]

definitely it helped me, and i always rate , thanks man.

if you dont mind we can continue in this,

A-hereunder example of VOIP senario and give me your commect.

       Phone1----G711---"CME_a"-------------------G729-------------------"CME_b"--------phone3

     phone 2------G711---

1-if phone 1 call phone2, no transcoding needed?

2-if phone 1 call phone 3, transcoding needed?, if needed, what CME is responsible for transcoding?, how it done, from both drection of voice traffic?

-------------------------------------------------------------------------------------------------

B-Unity Express used only for Voice mail?, or it has another functions?

C-if there is a CME router without PVDM module exist, can this router contain unity express?

D-when i access unity express from CME CLI, i can use below command:

UNATRAC-LON-CME#service-module service-Engine 0/0 session 

Trying 20.10.20.10, 2194 ... Open

UNATRAC-LON-VM#

right??

E-what is this service-engine 0/0?, is it the AIM module??

F-from the same CME router

UNATRAC-LON-CME#sh inventory

NAME: "2821 chassis", DESCR: "2821 chassis"

PID: CISCO2821         , VID: V07 , SN: FCZ1414707P

NAME: "VWIC2-1MFT-T1/E1 - 1-Port RJ-48 Multiflex Trunk - T1/E1 on Slot 0 SubSlot 0", DESCR: "VWIC2-1MFT-T1/E1 - 1-Port RJ-48 Multiflex Trunk - T1/E1"

PID: VWIC2-1MFT-T1/E1  , VID: V01 , SN: FOC14152FV4

NAME: "3rd generation two port FXS DID voice interface daughtercard on Slot 0 SubSlot 1", DESCR: "3rd generation two port FXS DID voice interface daughtercard"

PID: VIC3-2FXS/DID     , VID: V02 , SN: FOC14194Y9W

NAME: "PVDMII DSP SIMM with Two DSPs on Slot 0 SubSlot 4", DESCR: "PVDMII DSP SIMM with Two DSPs"

PID: PVDM2-32          , VID: V01 , SN: FOC14106C5S

NAME: "PVDMII DSP SIMM with one DSP on Slot 0 SubSlot 5", DESCR: "PVDMII DSP SIMM with one DSP"

PID: PVDM2-16          , VID: V01 , SN: FOC1251583D

NAME: "AIM Service Engine 0", DESCR: "AIM Service Engine"

PID: AIM-CUE           , VID: V03 , SN: FOC14171Z7Z

1- there is PVDM2-32, and PVDM2-16, how i can choose the PVDM needed for my network?

2-the AIM service engine 0, is it the Unity Express??

3-when i access it , i use service engine 0/0, why 0/0, it is AIM 0 only, there is no 0/0?

------------------------------------------------------------------------------

F-what is related configuration to PVDM?, i.e, is there any provisioning configuration commands?

----------------------------------------------------------

G-when transcoding done by PVDM, it it need any configuration or done automatically?, i.e if G711 tranlated in real time to G729, is it use a specific commands in the run config, or just the existance of PVDM make the transcoding done automatically?

------------------------------------------------------------

H-is there is any config needed to provision AIM?, or just access the service engine and config the voice mail?

I am very sorry for such long paragraph, but i really wanna learn from your knowledege

thanks my friend for your help as usual.

[Adrian Saavedra · Accepted solution]

Hello Ahmed,

Hope I'm answering all your questions

A-hereunder example of VOIP senario and give me your commect.

1-if phone 1 call phone2, no transcoding needed?

No. Calls between phones controlled under the same CME will use G.711 and both phones supports G.711.

2-if phone 1 call phone 3, transcoding needed?, if needed, what CME is responsible for transcoding?, how it done, from both drection of voice traffic?

No. Call will be in G.729 and will work since Cisco IP phones (besides G.711 and other codecs) supports G.729. If for some reason phone 3 doesn't support G.729, then CME_b needs a transcoding resource to connect the call successfully.

-------------------------------------------------------------------------------------------------

B-Unity Express used only for Voice mail?, or it has another functions?

Supports Voicemail, Integrated Messaging, Auto Attendant, IVR and Fax.

C-if there is a CME router without PVDM module exist, can this router contain unity express?

Yes.

D-when i access unity express from CME CLI, i can use below command:

Yes. That command is used to access CUE via CLI, although you can use GUI as well.

E-what is this service-engine 0/0?, is it the AIM module??

Yes.

F-from the same CME router

1-there is PVDM2-32, and PVDM2-16, how i can choose the PVDM needed for my network?

Depending on the requirements (i.e. connections to PSTN, conferencing, transcoding, etc) you will need to calculate the total number of PVDMs. For this you can use the Cisco DSP Calculator: http://www.cisco.com/web/applicat/dsprecal/dsp_calc.html

2-the AIM service engine 0, is it the Unity Express??

Yes.

3-when i access it , i use service engine 0/0, why 0/0, it is AIM 0 only, there is no 0/0?

The AIM is installed in slot 0, subslot 0.

------------------------------------------------------------------------------

F-what is related configuration to PVDM?, i.e, is there any provisioning configuration commands?

The most common is for conferencing and transcoding resources. Check this: http://www.cisco.com/en/US/docs/ios/12_3/vvf_c/interop/intcnf2.html
----------------------------------------------------------

G-when transcoding done by PVDM, it it need any configuration or done automatically?, i.e if G711 tranlated in real time to G729, is it use a specific commands in the run config, or just the existance of PVDM make the transcoding done automatically?

You configure the resources as shown in the link above. Once you get the resources registered and configured correctly, they will be invoked by CM/CME automatically when the situation demands.

------------------------------------------------------------

H-is there is any config needed to provision AIM?, or just access the service engine and config the voice mail?

You first configure IP connectivity to the module. Check this: http://www.cisco.com/en/US/docs/voice_ip_comm/unity_exp/design/design21/cuenwinf.html#wp1008330

Next you can access it via CLI or GUI for configuration and integration to CM/CME.
http://www.cisco.com/en/US/products/sw/voicesw/ps5520/products_configuration_example09186a008037f2a9.shtml#t11
http://www.cisco.com/en/US/products/sw/voicesw/ps5520/products_configuration_example09186a0080289ef0.shtml

Hope it helps. Thank you for the ratings.

-- Adrian.

[Ahmed Zein]

Dear Guys i am really happy with this co-operation speret , and i hope you more knowledge and more experiance and steping up in your carrer path,

thanks in advance .

and i will keep sending such questions in order to learn from experts

[Ahmed Zein]

Hello my friend i have an issue with CME b-ACD

could you please check this topic

https://supportforums.cisco.com/thread/2091840

[Ahmed Zein]

Hello my friend i have an issue with CME b-ACD

could you please check this topic

https://supportforums.cisco.com/thread/2091840