Maximum FXO ports on Cisco 3945

[Sharleen Suarez]

Hi,

Is it possible to configure 64 FXO ports on a Cisco 3945? It has been told in UC8.0 launch but I can only configure 48, 16 on the HWIC slots and 32 on the NM slot using four NM-HD-2V.

Thanks!

Sharleen

[AtefHashish]

In place of 2 NM-HD-2V, you should use 2 EVM-HD-8FXS/DID each with 2 EM-HDA-6FXO

[skilambi]

Yes you can using EVM, DSP calculator will also accept the configuration. Using Low complexity codec and no resources for transcoding/conferencing here is the output.

Router: 3945

IOS: 15.0(1)M

DSPs Required:

PVDM3-192: 1

Motherboard Slots:

Slot 1: PVDM3-192

Network Module 1: EVM-HD-8FXS/DID

Network Module 2: EVM-HD-8FXS/DID

Network Module 3: EVM-HD-8FXS/DID

Network Module 4: EVM-HD-8FXS/DID

Thanks

Srini

[Sharleen Suarez]

Thanks for the response. I configured 64 FXOs but I have a question, why is the DSP too large? Thanks.

[skilambi]

I noticed it and opened a case with the DSP calculator team. It was identified as a bug and it has now been fixed. I ran the same scenario and now you will see the correct results. If you decide not to allocate DSP for the base 8 port FXS module and only allocate DSP for FXO then it will be PVDM3-64. If you include the 8 FXS port then it will be PVDM3-128 which is what you would expect

Thanks

Srini

[aalejo]

HI Srini

Do you have the bug id?

Thanks

Alex

[skilambi]

Alex

Just to clarify this isn't an IOS bug just an issue back then with the Cisco DSP calculator tool which has been fixed. Hence there isn't any bug ID, just an email from the DSP team that the issue was fixed

Thanks

Srini

[aalejo]

Srini

It is happening on the gateway itselft.The gateways does not allow to configure the 128 channels using the PVDM2-128 when you have that type of analog card.

- Alex

[skilambi]

As per the DSP calculator, screen shot attached you can have 72 FXO (4 VIC2-4FXO and then 4 EVM modules with 6 FXO) but in one of the sheets I have the maximum listed is 64 for FXO. So that is the upper limit you might be running into? If you are only able to configure 64 channels then it does match this sheet that I have

Thanks

Srini

[aalejo]

Hi Srini

This is what i have:

PVDM3-128 configure as Flex complexity

EVM-HD-8FXS/DID

EM-HDA-6FXO

EM-HDA-6FXO

EVM-HD-8FXS/DID

EM-HDA-6FXO

EM-HDA-6FXO

VWIC2-2MFT-T1/E1

I have 128 channels available and 86 hardware channels. Should be enough.

When i tried to configured the second T1 it said that i need and extra DSP.

Looks very similar to the problems that you have with the DSP calculator but in the gateway itselft.

Thanks

- Alex

[skilambi]

If those are the only cards you have and you are using low complexity codec (G711) and you are not using any additional resources for conferencing or transcoding, then with 2 EVM 8 FXS each with 2 6 FXO and 1 VWIC2-2MFT you will be fine with PVDM3-128. Even the DSP calculator confirms the same. Open a case with TAC if it is an IOS issue

Thanks

Srini

[annya.martinez]

Hi Srini

This is an old post, but I have a similar situation where I need to configure several FXO ports on a Router. Is there any difference in using EVM modules instead of NM-HD-2V?

Thank you,

Annya

[skilambi]

The EVM uses the onboard PVDM3. I would always run the scenarios through the DSP calculator

Srini

[annya.martinez]

And how does EVM-HD-8FXS/DID module with 2 EM-HDA-6FXO work? I see it has only 1 RJ-21 port...

Thank you.

[skilambi]

Yes you can buy break out panels like Black box has one for the EVM module or you can use the classic punch down too

http://www.blackbox.com/Store/Detail.aspx/Distribution-Panel-for-Cisco-High-Density-Analog-and-Digital-Extension-Module-for-Voice-and-Fax/JPM2194A

I don’t work for this company. It is merely a suggestion

Thanks

Srini