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Kenny,<br>
<br>
A number of different options exist for redundancy, but they all depend
on your underlying network architecture and connectivity options. The
newest switches tend to have call agents and media gateways that are
separate, so you can have redundancy across your hardware and call
control geographically. Some older switches are more monolithic, so
you have more redundancy in your network since that has to survive more.<br>
<br>
You also find the world changes pretty dramatically when you go from
Asterisk (which I use generically to refer to any small-scale solution
of under 2k endpoints or so) to Big Iron - you pay a lot more money for
all sorts of redundancy and scalability, and as a result you solve
problems very differently (and have different options to solve
problems). Right now Asterisk can't exist without the big iron (5E,
MetaSwitch, Broadsoft, etc.) because it can't handle the call routing,
SS7 interop, etc. One can think of the smaller VoIP providers as basic
class 5 switches providing the traditional end-user connectivity and
not worrying about the bigger issues that will bedevil people as they
head into the interconnection world.<br>
<br>
If you can split your call control and media between geographical
locations, then you can set up as a CLEC in two colocations, and
interconnect to the necessary tandems to exchange traffic with two
unrelated circuits, and then have lots of room to lose one half of your
network without affecting core call control (how you get to your
customers is a different problem, of course). Switches can also
function in an emergency-standalone world as well. SS7 already has all
of the redundancy options via multiple A-links to the outside world. I
don't believe it's possible to interconnect with IP anywhere as a CLEC
since the PSTN infrastructure doesn't exist outside of the SS7
environment for all practical purposes. (Obviously, you can peer with
IP but that's not the same as interconnection from a PSTN perspective).<br>
<br>
If you can't split your call control, then you use SONET and other
self-healing architecture to buttress your network as much as possible
against fiber cuts, MUX outages, and other crashes with the hope that
you never lose both ends of your ring at the same time.<br>
<br>
Cheers,<br>
<br>
David.<br>
<br>
<hr size="2" width="100%"><br>
Kenny Sallee wrote:
<blockquote
cite="mid:4a80ecce0908110729v1fdd3f81k9c3419dedbe96398@mail.gmail.com"
type="cite">
<div>Yes IP makes it easier but you still have to 'plugin' to the
PSTN somewhere and in some fashion correct? Unless you have nothing
but SIP peering it does get a little more complicated (although I'm new
to the VoIP world and do not know SS7). Then you still have to worry
about your call processing platform: can it live with being greater
than x ms apart from it's redundant pair? What about CDR's and
reporting - how do you merge those coming from multiple sources? I
would think there's also rate center and latency issues as well with
outbound routing of calls (send calls out the cheapest carrier that
will allow it). I don't think any of it's impossible, but the presence
of IP doesn't remove all complexity.</div>
<div> </div>
<div>I like David's idea of a VoiceOps working group to help define
options. Sounds like fun</div>
<div>Kenny</div>
<div><br>
<br>
</div>
<div class="gmail_quote">On Tue, Aug 11, 2009 at 7:23 AM, Alex
Balashov <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:abalashov@evaristesys.com">abalashov@evaristesys.com</a>></span>
wrote:<br>
<blockquote
style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;"
class="gmail_quote">Seems to me like one of the main arguments for
moving to IP infrastructure - alongside the numerous arguments telco
people have against it - is that it makes this type of redundancy a lot
more achievable and cost-effective.<br>
<font color="#888888"><br>
-- <br>
Alex Balashov<br>
Evariste Systems<br>
Web : <a moz-do-not-send="true" href="http://www.evaristesys.com/"
target="_blank">http://www.evaristesys.com/</a><br>
Tel : (+1) (678) 954-0670<br>
Direct : (+1) (678) 954-0671<br>
Mobile : (+1) (678) 237-1775</font>
<div>
<div class="h5"><br>
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