ThatGuyGomer.Com » VoIP Q&A http://www.thatguygomer.com A boy and his blog Fri, 16 Oct 2009 19:47:44 +0000 http://wordpress.org/?v=2.8.5 en hourly 1 Cisco – Avaya http://www.thatguygomer.com/archives/50 http://www.thatguygomer.com/archives/50#comments Mon, 03 Mar 2008 22:14:35 +0000 gomer http://www.thatguygomer.com/archives/50 I had an interesting problem come up at work recently. I have a client who has 2 Cisco Call Manager 4.x clusters as well as a third Avaya solution. The Call Manager clusters are connected with the standard Cisco inter-cluster trunk. However, the Avaya was integrated into one Cluster as an H.323 gateway. The avaya is an S8500. So, the Call Manager cluster and the Avaya have been playing nicely all along with this H.323 gateway configuration, except that some of the features you expect out of a PBX don’t work. For example, even though call signaling works fantastic, the (cisco term) alerting name doesn’t work. This is an inherent limitation in the H.323 protocol stack. H.450.8 provides calling party information over H.323 trunks, but this is for the benefit of the called party. What my client wants is for the calling party to be alerted to whose phone is ringing (particularly useful to see when a call forwards or rolls to another extension). There is no such facility, however, in H.323. Luckily, the ITU foresaw the need for some of these supplementary services that fall outside the spec of H.323. To accommodate users with needs for more services, the ITU drafted some extensions (annexes) to H.323 to allow the tunnel of some SS7 protocols over H.323. Q.SIG (an ISDN signaling protocol) supports the services my client needs, so I chose to implement H.323 Annex M1 which defines Q.SIG tunneling over H.323. The call Cisco Call Manager offers the use of this standard as a configurable option. Allegedly, the Avaya S8500 does as well. So, my client’s Avaya guy has turned on the Q.SIG tunneling, and I in turn do the same. Well, now, we are worse off than before. Now, instead of the two PBXs exchanging the regular 4 or 5 digit extensions in call alerting, we are getting full 10 digit DID numbers instead. The expected behavior was to see the display of names in call alerting, including the “alerting name” displayed on the calling party’s phone corresponding to the phone ringing at the other end.

I can find tons of documentation on the web on integrating an Avaya S8500 and a Cisco Call Manager cluster using just straight H.323, and this was in fact working. I can also find tons of documentation about integrating the two using Q.SIG over an ISDN PRI. However, I can’t find any information about enabling Q.SIG over the H.323 trunk. I’m currently working with Cisco TAC to see if this configuration is even supported.

So, if anyone reading this has any experience with getting supplementary services working between these 2 PBXs, please let me know.

]]> http://www.thatguygomer.com/archives/50/feed 1 BroadVoice http://www.thatguygomer.com/archives/49 http://www.thatguygomer.com/archives/49#comments Mon, 03 Mar 2008 21:41:42 +0000 gomer http://www.thatguygomer.com/archives/49 So, as some of you may already know, I have been using VoIP exclusively at home for a while, now. I currently use a company called BroadVoice, based right here in MA. So far, I’ve had no complaints with the service. For quite some time, I was using it strictly with a soft phone, but when Jamie moved in, she wanted to be able to use her analog cordless phone. I thought why not, so I went ahead and bought an Analog Telephone Adapter and configured it for use with Broadvoice. The whole process was amazing simple. I have been using the default G.711ulaw codec for my voice calls (not a huge concern at cable modem speeds – 80K per call is fine), but I have to see what other codecs Broadvoice supports. I have to say, though, for the price, and the service I receive for that price, BroadVoice is well worth it. I spend roughly $25 a month, and I have a phone number local to my town, and have unlimited calling any where in the US and like 20 or so more countries. That’s right, no long distance charges. I’ve been using the service whenever I work from home (with caller-id blocking), and comparable use on my old Verizon land line would have cost me hundreds of dollars a month. Even when I had my land line, and I wasn’t using it, it still cost me more than $30 a month, so I’m still saving. I think once you look at the features available and calling areas for the plan, Broadvoice works out to be cheaper than even Vonage. I highly recommend them to any one for residential use.

But see, that’s where I start to have a problem with them. I’ve recently confirmed with them that on an account, though you can have up to 3 phone numbers (including an 800 number), you can only have 1 active call (call waiting / 3-way calling, too). So, the service is not suitable for building a SIP trunk from an IP PBX for business use, unless you only have a a need for a single line. What I would like to find is a company that caters to businesses thus allowing calls to be trunked across SIP. Other things I would like to see supported, too, would be multiple DID numbers. That is to say, let’s say I start a business and I have 4 people working for me. I want to be able to have 5 people on calls, and still receive any number of incoming calls to my auto attendant. I would also like to be able to have a toll free number, as well as DID numbers in the area codes in which I do the most business. If anyone out there knows of such a company, please let me know. This would be a huge help for me.

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