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Community Member

Small office VoIP system

Good morning everyone,


I am currently defining the architecture for a very simple VoIP network that is to be installed in a small office (about 70 VoIP extensions). Initially, we don't want to include any special feature, just the internal voice IP service and the ability to make up to 4 simultaneous external phone calls through PSTN.

We are going to acquire a Cisco 2921 Router, the SL-29-UC-K9 Unified Communications licence and a VIC2-4FXO. 

I have been reading about ISR G2 licensing, but I am still not sure of fully understanding what we need for this project. My question is, does the UC licence for the Cisco 2921 include the FL-CME licence to use the Call Manager Express functionality? do we need something else? any special license for the FXOs functionality?


Thank you for your help





if it is bundle so you will

if it is bundle so you will see cme licences in name


C2921-CME-SRST/K9 2921 Voice Bundle w/ PVDM3-32,FL-CME-SRST-25, UC License PAK

and so you will need 45 more cme licences

Hall of Fame Super Silver

No, but you get full umbrella

No, but you get full umbrella of products, including if you decide to add MRA, IMP with Jabber, etc.

What are you doing for voicemail as you did not call out CUE in your approach which is additional cost for hardware and licensing?

The BE6K bundles are very price competitive.


Hall of Fame Super Silver

If I was in your shoes I

If I was in your shoes I would consider BE6K which would give you CUCM/Unity Connection/IM&P/and other apps for bundled BE6K user license.

voice router + fxo card +

voice router + fxo card + be6000 is it cheaper than voice router + fxo ?

Community Member

Thank you guys for your

Thank you guys for your answers,

Actually, it's my first contact as a developer with VoIP and UC Cisco technology... so I would like to keep it simple at the beginning: just internal voip phone calls and the possibility to ring pstn extensions. Our budget is very limited too... so I need to stick to the hardware that I told you in the previous message: 2921 + fxo card. 

As far as I have read, SRST functionality is very useful when you have several nodes, to provide survival to each local node that loses connectivity with a centralized call manager. But in our scenario, with a single node... I think we can give up this functionality.

So, we only have budget to purchase any other license that could be necessary to accomplish this small project. so the key question is: does SL-29-UC-K9 Unified Communications License include Call Manager Express functionality and the ability to use de FXO card to make pstn phone calls as well? because that will be more than enough for us...


thank you very much



VIP Blue

Simple and small VoIP network

Simple and small VoIP network ? You may consider SMB line of Cisco products. Something like SPA5xx or SPA3xx phone in SIP mode as end user phone. Any SIP PBX. You are not limited to Cisco product, there are so many solutions based on Asterisk software. Some of them have PSTN interface cards inside already, or you can use third party gateways. Either Cisco's or something like Berobox.

Advantages: cheap, but still very reliable solution, flexible in features, it's possible to maintain high level of security, scalable from few lines to few hundreds lines. Once you designed first network, you can reuse the solution design easily.

Disadvantages: it require skilled architect (you) to design reliable network, Cisco support for SMB segment devices is poor.

I designed several VoIP network based on SPA504G and cheap generic PC with Asterisk software (running on configuration I designed). The smallest network have about 20 users, the largest have few thousands users in 7 countries ...


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