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Basic CME Questions

Unanswered Question
Jul 9th, 2014
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I have a few really basic Call Manager Express Questions I was hoping someone could answer.  I'm considering deploying CME version 10 on a Cisco 2911 Router and I want to use SIP Phones which will connect to CenturyLink via PRI.  All of that should work just fine.  The questions I have are:

 

1.  We have people that work from home so I want to get them a SIP phone and allow them to feel as if they are in the office with intercom, extension dialing, etc.  I don't want to use a VPN.  Can I do this with CME version 10 and does anyone know of any trusted guides for doing this?

2.  Will the 7941-G phones support a version of SIP that works with CME?

Thanks for any advice!

 

 

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Emmanuel Valdez Wed, 07/09/2014 - 17:15
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Hi,

The best practices is to deploy a VPN for remote users, if you don´t want to implement a router for every user at home to establish a VPN to the cooperative you can use Phone VPN feature, this permit to have a SSL VPN Server into 2911 and the IP phone is the client. Only few IP Phones support this feature, you have to check the compatibility before to deploy.

7941-G support a SIP firmware but I really recommend you to work with native SCCP firmware.

If it was useful please rate.

Regards.

tditechsolutions Wed, 07/09/2014 - 17:21
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Thank you Emmanuel...this leads me to a question. How do providers like Ring Central, etc. provide that service then?  Their phones are all SIP phones and you can plug them in pretty much anywhere on the Internet.  Just curious why I could not do this with a Cisco SIP phone?

Emmanuel Valdez Wed, 07/09/2014 - 18:34
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Hi,

At this momment 2911 can act like call processor or CUBE only, if you have security license you can enable IOS Firewall and NAT your CME, you have to NAT signaling port for example 5060 for SIP and RTP ports. Aditional you have to disable ALG on the router or you will have problems registering your remotes IP Phones.

You can test with NAT first and then enable Firewall if you have the license. But I really don´t recommend it, you can have a toll fraude attack from Internet, you may block this declaring safe networks that can make calls from CME, the problem is that you don´t know that networks because they will be from Internet.

If it was useful please rate.

Regards.

tditechsolutions Wed, 07/09/2014 - 19:12
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Thanks again Emmanuel. It's so frustrating because I know I can get a simple shortel system and have remote users with no issue...I wish cisco would make this a tad easier for remote workers who I know won't understand even what a VPN is let alone connect to know just to use their phone 

Emmanuel Valdez Thu, 07/10/2014 - 08:24
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Hi,

CME is an old solution with EoL, at this momment you could accomplish your requirements with CUCM and Expressway Technology, version 10 offers this for all features for example voice, IM & Presence, etc, like Shoretel.

Regards.

 

tditechsolutions Thu, 07/10/2014 - 09:13
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Thanks Emmanuel. Question. This is for a business with 25 people... Chuck is way overkill for that. So what exists then if cme is end of life??

Emmanuel Valdez Thu, 07/10/2014 - 10:19
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Hi, 

Yes the initial bundle includes 25 users with voice, voicemail, IM & Presence feature and you can use your actual CME like PSTN Gateway and Survivable.

This is a solution called Business Edition 6000, if you need more information you can check the link below or contact a Cisco Partner.

http://www.cisco.com/c/en/us/products/unified-communications/business-ed...

Additional ask for the Expressway Technology that is incuded in this solution and doesn´t need aditional licensing. 

Regards.

Emmanuel Valdez Wed, 07/09/2014 - 17:37
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Hi,

Yes you can do it but this is not recommended by security because all your traffic is not encrypted and is very easy for a phreaker to attack your telephony system. With Phone VPN you can plug the IP Phone anywhere in the world (you only need internet connection) and make calls like in the office.

Many telephony providers accomplish this by nating the call procesor and authenticating the phone with user and password, but security is minimum, others use SIP Proxy servers.

Regards.

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