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Yes, but this depends on your deployment setup and policies. Obviously,
you cannot support all features with all UAs. Three-way conferencing
for example. There's no guarantee that REFER and NOTIFYs work for three
random UAs from different vendors. There are still too many bugs
around. So, you need to say: If you have this and that UA, you will
probably not get three-way conferencing. Not much difference from
saying: If you have this and that UA, you may experience service
outages.<br>
<br>
There are several ways of creating server-side redundancy and
scalability. Unfortunately, none are trivial. There are three I have
heard have been successfully used in large-scale setups:<br>
1. Cacheless usrloc with a mysql cluster as back-end DB combined with
implementation of the Path header (to find the registrar of a given
UA). No replication across servers<br>
2. Multiple SER registrars, each with a standalone, local DB and where
SIP is used to replicate registrations. By storing replications from a
peer in a location_peer1 table and then lookup using this table, you
can route INVITEs to the registrar being able to pinhole the NAT in
front of a given UA<br>
3. Each SER is connected to a single mysql DB cluster as in #1, but
since usrloc also is in memory (cacheless usrloc is not used),
replication is done between the SER servers and save_memory() is used
to store the location only in memory (the registrar updates the cluster
with save())<br>
<br>
Each of these three can be combined with either:<br>
a. call-id sticky front-end load balancer (commercial or modified LVS) <br>
b. DNS SRV<br>
c. Linux HA creating two and two peers<br>
<br>
Only b) combined with either 1) or 3) or 2+c) can give geographic,
client and server-side redundancy and scalability.<br>
<br>
Scalability and redundancy is sort of a pet project of mine... I would
like to see a simple, clear-documented and code-supported setup that
satisfies most common requirements. Currently I'm leaning against #2
(which actually can be implemented in vanilla SER 0.9.x, but would be
easier and better with built-in support). I'm thinking about a setup
where two and two servers are peers to eachother using Linux HA. Both
servers would have one active SER instance and one inactive ready for
taking over for the peer.<br>
<br>
I have posted this overview to:<br>
<a class="moz-txt-link-freetext" href="http://www.iptel.org/drupal/failover_redundancy_and_scalability_overview">http://www.iptel.org/drupal/failover_redundancy_and_scalability_overview</a><br>
<br>
See also:<br>
<a class="moz-txt-link-freetext" href="http://www.iptel.org/drupal/ser/wishlist">http://www.iptel.org/drupal/ser/wishlist</a><br>
<br>
g-)<br>
G.Jacobsen wrote:
<blockquote
cite="midCPEBJFBCDCKKIHJAODHCOEHNCHAA.g_jacobsen@yahoo.co.uk"
type="cite">
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<div><span class="606391420-06072006"><font color="#0000ff"
face="Arial" size="2">Samuel,</font></span></div>
<div><span class="606391420-06072006"></span> </div>
<div><span class="606391420-06072006">Do you happen to know what
percentage of UAs out there are really </span>"Compliant" UAs <span
class="606391420-06072006">?</span></div>
<div><span class="606391420-06072006"></span> </div>
<div><span class="606391420-06072006"><font color="#0000ff"
face="Arial" size="2">My impression so far regarding SRV DNS records
is that they are theoretically a nice feature but unfortunately almost
useless since one needs to cater for those non-compliant UAs anyway. I
would love to be convinced of the contrary.</font></span></div>
<div><span class="606391420-06072006"></span> </div>
<div><span class="606391420-06072006"><font color="#0000ff"
face="Arial" size="2">Can anyone supply real usage figures regarding
compliant/non-compliant UAS ?</font></span></div>
<div><span class="606391420-06072006"></span> </div>
<div><span class="606391420-06072006"><font color="#0000ff"
face="Arial" size="2">TIA</font></span></div>
<div><span class="606391420-06072006"></span> </div>
<div><span class="606391420-06072006"><font color="#0000ff"
face="Arial" size="2">Gerry</font></span></div>
<div><span class="606391420-06072006"></span> </div>
<div> </div>
<div> </div>
<blockquote>
<div class="OutlookMessageHeader" dir="ltr" align="left"><font
face="Tahoma" size="2">-----Original Message-----<br>
<b>From:</b> <a class="moz-txt-link-abbreviated" href="mailto:serusers-bounces@lists.iptel.org">serusers-bounces@lists.iptel.org</a>
[<a class="moz-txt-link-freetext" href="mailto:serusers-bounces@lists.iptel.org">mailto:serusers-bounces@lists.iptel.org</a>]<b>On Behalf Of </b>samuel<br>
<b>Sent:</b> Donnerstag, 6. Juli 2006 14:52<br>
<b>To:</b> Ritesh Jalan<br>
<b>Cc:</b> seruser List<br>
<b>Subject:</b> [Bulk] Re: [Serusers] Global Failover Server<br>
<br>
</font></div>
<br>
Look at RFC 3623.<br>
Cofigure two SRV entries in
your DNS, one pointing to the UAS SERver and another to the UK server.
"Compliant" UAs will try to contact the other proxy upon failure of
their current one.<br>
<br>
Samuel.<br>
<br>
<div><span class="gmail_quote">2006/7/5, Ritesh Jalan <<a
href="mailto:ritesh.j@net4.in">ritesh.j@net4.in</a>>:</span>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">
<div>
<div bgcolor="#ffffff">
<div><font face="Arial" size="2">Hi All</font></div>
<div> </div>
<div><font face="Arial" size="2">Pls. guide me how can we
implement failover on SIP Server located globally, Like one server in
USA another in UK. </font></div>
<div> </div>
<div> </div>
<div> </div>
<div><font face="Arial" size="2">Ritesh Jalan <br>
Mobile: 91-9818616329 <br>
MSN: <a onclick="return top.js.OpenExtLink(window,event,this)"
href="mailto:ritesh_jalan@hotmail.com" target="_blank">ritesh_jalan@hotmail.com</a>
<br>
</font></div>
</div>
</div>
<br>
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<br>
</blockquote>
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<br>
</blockquote>
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