<div dir="ltr">Well at 5 am in the morning while thinking on this topic the only thing ringing in my mind is a mechanism similar to IP to IP Gateway. Here is the main concept.<div><br></div><div style>1. We have number of SIP servers running, say <a href="http://sip1.mydomain.com">sip1.mydomain.com</a>, <a href="http://sip2.mydomain.com">sip2.mydomain.com</a> ... <a href="http://sipN.mydomain.com">sipN.mydomain.com</a>, each serving domain <a href="http://mydomain.com">mydomain.com</a> and a SIP client A can select any one of these servers through DNS look-up (or whatever way possible) and registers to that server. Lets call these servers as Base Nodes.</div>
<div style><br></div><div style>2. Upon successful registration of client A to server <a href="http://sip1.mydomain.com">sip1.mydomain.com</a>, this Registrar Node fires an Event, which can be subscribed by a back-end SIP server, lets call it Super Node. This event will only contain following things,</div>
<div style><br></div><div style> a). User part of all Contact URIs of client A with Expiry.</div><div style> b). Registrar Node information e.g. its IP address + Port.</div><div style> c). SIP domain of client A. (in case of multi-domain setup)</div>
<div style><br></div><div style>3. Super Node stores this information in some db back-end (memcache, redis, mysql etc.). This is sort of back-to-back register process but without SIP or authentication, since that has already been handled on Based Node anyway. The Super Node only needs to know which user is registered on which Base Node e.g. user 1001 is registered on node <a href="http://sip1.mydomain.com">sip1.mydomain.com</a>, user 1203 is registered on <a href="http://sip6.mydomain.com">sip6.mydomain.com</a> and so on.</div>
<div style><br></div><div style>4. When a SIP client B tries to send INVITE or MESSAGE or SUBSCRIBE to SIP client A. The SIP request will arrive on Base Node it is currently registered with, say <a href="http://sip2.mydomain.com">sip2.mydomain.com</a>. This node will first do local look-up for location of client A. Upon failure it will forward request to Super Node, which will do a look-up on Event database and finds that client A is registered on node <a href="http://sip1.mydomain.com">sip1.mydomain.com</a>, so it will send SIP redirect response 302 to requester Base Node. Now the request source node knows the address of request destination node, where it will send request next and they both, while acting as independent SIP servers, establish SIP session between caller and callee. This should work regardless if both nodes serve same or different SIP domains.</div>
<div style><br></div><div style>5. The Super Node will also give us global presence of all users currently registered to all Base Nodes, which may be useful for management and monitoring etc.</div><div style><br></div><div style>
Pros:</div><div style>1. Completely independent of network topology and SIP.</div><div style>2. Will work seamlessly for multi and federated domains.</div><div style>3. Scale-able in every direction.</div><div style>4. Minimal overhead for session establishment. Once supper node return destination base node address in SIP redirect response, session will establish directly between source and destination base node. Further optimizations are possible, e.g. base node can cache destination base node returned by supper node for any particular user and avoid querying super node for recurring SIP sessions.</div>
<div style><br></div><div style>Cons: </div><div style>1. Well, the key problem i can guess is of course the Event database size and speed, as it will have information on every user registered to every Base Node. I suggest memory cache db such as Redis would be idle for this storage.</div>
<div style>2. Bandwidth consumed in Event transport. We can apply compression and make event queues as optimization.</div><div style><br></div><div style>Comments and suggestions are highly welcome.</div><div style><br></div>
<div style>Thank you.</div><div><br></div><div><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Apr 4, 2013 at 2:05 PM, Vlad Paiu <span dir="ltr"><<a href="mailto:vladpaiu@opensips.org" target="_blank">vladpaiu@opensips.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello all,<br>
<br>
We would like to get suggestions and help on the matter of distributing the user location information.<br>
Extending the User Location with a built-in distributed support is not straight forward - it is not about simply sharing data - as it is really SIP dependent and network limited<br>
<br>
While now, by using the OpenSIPS trunk, it is possible to just share the actual usrloc info ( by using the db_cachedb module and storing the information in a MongoDB cluster ), you can encounter real-life scenarios where just sharing the info is not enough, like :<br>
- NAT-ed clients, where only the initial server that received the Register has the pin-hole open, and thus is the only server that can relay traffic back to the respective client<br>
- the user has a SIP client that only accepts traffic from the server IP that it's currently registered against, and thus would reject direct traffic from other IPs ( due to security reasons )<br>
<br>
We would like to implement a true general solution for this issue, and would appreciate your feedback on this. Also we'd appreciate if you could share the needs that you would have from such a distributed user location feature, and the scenarios that you would use such a feature in real-life setups.<br>
<br>
<br>
Best Regards,<span class="HOEnZb"><font color="#888888"><br>
<br>
-- <br>
Vlad Paiu<br>
OpenSIPS Developer<br>
<a href="http://www.opensips-solutions.com" target="_blank">http://www.opensips-solutions.<u></u>com</a><br>
<br>
<br>
______________________________<u></u>_________________<br>
Users mailing list<br>
<a href="mailto:Users@lists.opensips.org" target="_blank">Users@lists.opensips.org</a><br>
<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users" target="_blank">http://lists.opensips.org/cgi-<u></u>bin/mailman/listinfo/users</a><br>
</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br><div><span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Mit freundlichen Grüßen</span></div>
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Muhammad Shahzad</span><br style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">------------------------------</span><span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">-----</span><br style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">CISCO Rich Media Communication Specialist (CRMCS)</span><br style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">CISCO Certified Network Associate (CCNA)</span><br style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Cell: +49 176 99 83 10 85</span><br style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">MSN: </span><a href="mailto:shari_786pk@hotmail.com" style="color:rgb(17,85,204);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)" target="_blank">shari_786pk@hotmail.com</a><br style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Email: </span><a href="mailto:shaheryarkh@googlemail.com" style="color:rgb(17,85,204);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)" target="_blank">shaheryarkh@googlemail.com</a>
</div>