Hello list, When you have an asterisk box connected between the VoIP phones and an PSTN gateway what is the role of asterisk. Proxy server: stateful or stateless? From what i read in the: "Understanding the SIP, second edition" from Alan B. Johnston i think that asterisk is a stateful proxy server as well as registration server. Am I right? Can asterisk be configured to work as redirect server or stateless proxy or i am totally in the dark and don't understand correctly? And if you know other (better) books for SIP please tell me. thank you and have a great day, v
On Wed, 2008-11-19 at 12:33 +0200, Valentin Bud wrote:> When you have an asterisk box connected between the VoIP > phones and an PSTN gateway what is the role of asterisk. Proxy server: > stateful or stateless?Close, but not quite. Actually, Asterisk is what we call a back-to-back user agent. The most basic difference between a proxy and a back-to-back user agent is that with a proxy, a single call gets passed *through* the proxy and on to the destination. The proxy is not the destination of the call. With a back-to-back user agent, Asterisk is the destination of one call (in this case, the VoIP call), and then it creates a whole new call on the other side (to the PSTN in this case). It then acts as an endpoint to both calls, and sits in the middle and bridges the two calls, all while doing any necessary protocol or codec conversion between the two calls. Make sense? -- Jared Smith Training Manager Digium, Inc.
On Wed, 2008-11-19 at 12:33 +0200, Valentin Bud wrote:> i think that asterisk is a stateful proxy server as well as > registration server.To answer the second portion of your question (which I forgot to do in my earlier email)... yes, Asterisk can be a registration server as well. -- Jared Smith Training Manager Digium, Inc.
Hello Mr. Smith, Thank you very much for you time and explanations. I just started to take this VoIP business serious and as i mentioned in my previous email, I took a SIP book. If you know any kind of books that are suitable for a beginner please let me know. I started to read SIP books because i have an ackward problem with an asterisk box and i really have to know the protocol to understand what happens there. thanks once again and a great day, v On Wed, Nov 19, 2008 at 4:55 PM, Jared Smith <jsmith at digium.com> wrote:> On Wed, 2008-11-19 at 12:33 +0200, Valentin Bud wrote: >> i think that asterisk is a stateful proxy server as well as >> registration server. > > To answer the second portion of your question (which I forgot to do in > my earlier email)... yes, Asterisk can be a registration server as well. > > > -- > Jared Smith > Training Manager > Digium, Inc. > > > _______________________________________________ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users >
Jared Smith had written:> To answer the second portion of your question (which I forgot to do in > my earlier email)... yes, Asterisk can be a registration server as well. > > -- > Jared Smith > Training Manager > Digium, Inc.Valentin Bud wrote:> Hello Mr. Smith,<snip>>If you know any kind of books that are suitable for a beginner please letme know. Hi Valentin, I really like the book "Asterisk: The Future of Telephony, Second Edition" authored by some guy named Jared Smith... Coincidence? You be the judge... http://oreilly.com/catalog/9780596510480/ :)