<div>Or just tell your clients that cool technology comes at a cost - that cost is more downtime due to other problems mentioned earlier in this thread and the inherint problems of sharing voice and data on the same medium....Actually, it's an interesting problem to solve from both the core and cpe perspectives that all revolve around which vendors you use, business requirements, and cash (with cash being the first variable)...</div>
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<div>On a curiosity note - why would you even need to interconnect with SS7 to the PSTN when you can SIP peer to all the major carriers? There can be an argument for backup to SIP peering that makes sense. Maybe it's cheaper? But outside of those what other benefits are there (don't misread my tone here - I'm really asking)?</div>
<div>Kenny<br><br></div>
<div class="gmail_quote">On Tue, Aug 11, 2009 at 6:45 PM, David Birnbaum <span dir="ltr"><<a href="mailto:davidb@pins.net">davidb@pins.net</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote">
<div text="#000000" bgcolor="#ffffff">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>
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<br>Kenny Sallee wrote:
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<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>
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<div>I like David's idea of a VoiceOps working group to help define options. Sounds like fun</div>
<div>Kenny</div>
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<div class="gmail_quote">On Tue, Aug 11, 2009 at 7:23 AM, Alex Balashov <span dir="ltr"><<a href="mailto:abalashov@evaristesys.com" target="_blank">abalashov@evaristesys.com</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT: rgb(204,204,204) 1px solid; 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 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>
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