atcomsystems.ca/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones What is SIP anyway?

No S##t.

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For anyone just getting into VOIP as I am, this is what I understand so far. SIP is only part of a host of protocols that work together. You got to start learning from a point of reference. So as you investigate SIP, you will also see MCGP, UDP, RTP, RTCP, SDP, . . . . So it's not all you need to understand. SIP is responsible for the call setup (Session initiation) Once the session (call) is set up, SIP's job is done until you call upon it again (make another request for a service). To give you a real life example - remember that SIP to SIP calls are switchless. In my first experience with my own SIP equipment I was able to make a call from one Comdial EP200 softphones to another EP200 soft phones and then walk over and turn off my MP5000 switch. My call was still connected. If I made another request (try to transfer the call) the call was terminated. Now if I made a call from an EP200 out through a gateway in the switch to the outside world or a digital set in the switch, the call was terminated if I turn off the MP5000. So my approach to this is to see what happens here when I do that there.

Print this one and take it to the bath room for reading material.


https://www.sipcenter.com/sip.nsf/h...rge d_Communications_With_SIP_lb2343.pdf

As for SIP security, read this one.

https://www.sipcenter.com/sip.nsf/html/Session+Initiation+Protocol+and+Security


[This message has been edited by MARK3906 (edited April 08, 2005).]

[This message has been edited by MARK3906 (edited April 08, 2005).]

Coral:
You are correct that SIP does not provide encryption with one exception. Zultys is a SIP IP-PBX that provides 128 bit encryption. This hurdle is already being overcome.

But, once again that is proprietary and not a standard, thus not SIP. When SIP FINIALLY gets a true standard we will see. Right now it's simply 16 basic features that are generally considered the standard.



[This message has been edited by Coral Tech (edited April 09, 2005).]

Coral: I would like to think that people could freely present some of the things they learn along the way as we all embark on this journey of IP telephony without being afraid that YOU are going to come along an correct them. You can pick this thing to death if you want to. Basically what you are acomplishing is aleinating yourself from a group of people who could collectively learn something from each other. The only real thing I have learned from you so far is that you're going to have the last word.

aweaver: Fill me in. I don't care if Zultys added a little piece of propriatary brilliance in to get to their product to where they want it to be. But you might have to talk REAL LOUD so I can hear you.

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Alrighty then let me wade in on this. SIP is a standard ratified by the IETF. It is in it's infancy. Call it phase one. So what if there are only 16 features in phase one. Coral Tech - you are either coming across as one who believes that SIP sucks or you are playing Devil"s advocate..which is it? I have SIP working in my office and evaluate it based on feature set releases. What platform has been released with the full working complement of features? Don't let your short field of vision believe that your platform is the only working one. I have been in this business since 1976 and if I cut off both hands I still could count the number of Tadiran installs I come across. I'm in the ninth largest metropolitan area in the US and encountered zero. That being said I am not impressed with the current versions of VOIP or SIP. I only see value in VOIP tying offices or teleworkers together. Still evolving.. too soon to call. Remember fiber to the desk top, CTI (you'll never sell another phone as PCs will replace them), PC based VOIP gateways..all of them were more bust than balls. This bickering is like my brother can beat up your brother shit. I'll press forward with SIP and see what it grows into. Right now I'll have another SIP of cold beer. LOL.

[This message has been edited by RATHER BE FISHING (edited April 09, 2005).]

https://www.cisco.com/en/US/tech/tk652/tk701/technologies_white_paper09186a008009294d.shtml
https://www.cisco.com/en/US/tech/tk652/tk701/technologies_white_paper09186a0080092949.shtml
https://www.cisco.com/en/US/tech/tk652/tk701/technologies_white_paper09186a00800a9818.shtml
I know yall arent big Cisco fans, but they have good documents.

Nice documents. Crap implementation. I can show many Fortune 500 deinstalls due to lack of perceived value. I ran across a car dealership last week who lamented that when multiple calls ring in that they can't proceed to the second and third call until the first call is transferred. If its parked or on hold they can't get to sucessive calls. Whew thats innovation.

CISCO's approach here now is to get a small presence started with a large organization and very slowly bring more phones on line within the organization. The large installs don't get the attention around here like they use to, unless they are the one's they had and then lost at the contract signing.

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Mark, I am simply pointing out what you are calling SIP is not true SIP. I don't want to rain on you parade but since we are in this industry we need to be precise in calling something what it is. If you want to call it a SIP compliant system, with added features..thats great. When and if someone sits down and makes SIP a functioning standard written in stone. I am not here to have the last word by any means.

I cannot tell you how many times I have had to go in after Cisco and explain the customer about the Cisco system to the customer. Then have that customer go back and ask the cisco salesperson what I told them to ask them and if they said they could do it to get it in writing...needless to say they wouldn't. Accuracy, we have to watch what we are selling AND be precise to what is going on.

Rather, thats the way the system works. You can't take a second call. The other thing that's funny if you don't ask about MOH and buy a system be ready for that sticker shocker. People that have the previous AVVID systems...well lets say that ready the dumpster because to use any of the new tech you have to do a forklift. Remember guys, the MIS people are not stupid, they just need to be educated. It's easy to go into a business that gives the IT guy all the responsibilty and start talking his lingo IP and this and that. You have to make him think about more than that, and THAT is why we have to show and explain things so that he doesn't feel like the phone system is this alien antiquated piece of equipment. I have meeting go for more than 2 hours just explaining the the differences of IP and TDM. Trust me, I deploy a TON of IP in the field but where and when it makes sense.