<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Verdana; font-size: 10pt; color: #000000'>In a perfect world, yes. However, depending on how your L2/L3 links are set up, it may be possible from some phones to register on each router. Definitely not ideal, and it should be avoided, however, it might be possible. With a dial peer on each router, you cover this scenario.<br><br>HSRP is really only used to advertise to the phones where to register. Everything else is configured with the appropriate router address, most likely a loopback address. So, it's conceivable that the two routers can talk to each other via L3 via some advertised route, but not via L2 (over which HSRP is handshaked), in that case, each router will advertise it is the HSRP active router.<br><br>That's just me and my "try to cover every scenario possible" attitude. It's helped me out in some cases, bitten me on the ascot tie others. ;)<br><br>Then again, I don't try to be an L2/L3 expert and have been known to be laughed out of a network meeting trying to accomodate a scenario that costs 10K to provision and will happen once every election of a pope (that one sounds better in Italian). ;)<br><br><br><br><br><br>---<br>Lelio Fulgenzi, B.A.<br>Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1<br>(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)<br>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^<br>"Bad grammar makes me [sic]" - Tshirt<br><br><br>----- Original Message -----<br>From: "Bill Greenwood (US)" <bill.greenwood@us.didata.com><br>To: cisco-voip@puck.nether.net<br>Sent: Sunday, July 12, 2009 4:20:02 PM GMT -05:00 US/Canada Eastern<br>Subject: Re: [cisco-voip] Redundancy Options for CME<br><br>
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<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Thinking more about this:</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">If both routers run CME, on the standby router a general dial
peer for the phones would point to the primary router. This dial peer would
not be needed on the primary router as if it was up it would have the phone
registered locally. This dial peer on the standby router would be in place all
the time routing calls from the PSTN to the primary router under normal
operation. In the case where the primary router has failed then the phones
would register and create more specific dial peers which would route the call
locally to the phones. Does that sound correct?</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Bill</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"> </span></p>
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<p class="MsoNormal"><b><span style="font-size: 10pt; font-family: "Tahoma","sans-serif";">From:</span></b><span style="font-size: 10pt; font-family: "Tahoma","sans-serif";"> Lelio Fulgenzi
[mailto:lelio@uoguelph.ca] <br>
<b>Sent:</b> Sunday, July 12, 2009 4:03 PM<br>
<b>To:</b> Bill Greenwood (US)<br>
<b>Cc:</b> cisco-voip@puck.nether.net<br>
<b>Subject:</b> Re: [cisco-voip] Redundancy Options for CME</span></p>
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<p class="MsoNormal"> </p>
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<p class="MsoNormal"><span style="font-size: 10pt; font-family: "Verdana","sans-serif"; color: black;"><br>
Each router would have dial-peers pointing to the other router for each set.
There is a default setting (in SRST anyways) that prevents a routing loop via
H323.<br>
<br>
I had a similar question, and it was discussed briefly on the list. One of the
Cisco folk told me about the routing loop prevention. That's key. Because it's
on by default, it helps.<br>
<br>
Here's a press release talking about it (in very general terms). <br>
<br>
http://www.cisco.com/en/US/prod/collateral/routers/ps5854/prod_case_study0900aecd80424090_ns431_Networking_Solutions_Case_Study.html<br>
<br>
<br>
---<br>
Lelio Fulgenzi, B.A.<br>
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1<br>
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)<br>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^<br>
"Bad grammar makes me [sic]" - Tshirt<br>
<br>
<br>
----- Original Message -----<br>
From: "Bill Greenwood (US)" <bill.greenwood@us.didata.com><br>
To: cisco-voip@puck.nether.net<br>
Sent: Sunday, July 12, 2009 3:43:39 PM GMT -05:00 US/Canada Eastern<br>
Subject: Re: [cisco-voip] Redundancy Options for CME<br>
<br>
<br>
</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Even if the configurations are synchronized which would allow
for the phones to register with either router, how would the calls from the
PSTN be handled? If a call was received on the router that was not the
primary it would see the phone as not being registered and forward to voice
mail. There needs to be some method of having the routers communicate
with each other similar to a publisher and subscriber. I have not been
able to find anything to allow for this communication. Can the second
router be configured with SRST? But that still leave the question on the
PRIs, if both are connected to the primary router and it fails then you are
left with no connection to the PSTN.</span><span style="color: black;"></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"> </span><span style="color: black;"></span></p>
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<p class="MsoNormal"><b><span style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: black;">From:</span></b><span style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: black;"> mthompson729@gmail.com [mailto:mthompson729@gmail.com] <br>
<b>Sent:</b> Sunday, July 12, 2009 3:11 PM<br>
<b>To:</b> Bill Greenwood (US)<br>
<b>Subject:</b> Re: [cisco-voip] Redundancy Options for CME</span><span style="color: black;"></span></p>
</div>
<p class="MsoNormal"><span style="color: black;"> </span></p>
<p class="MsoNormal"><span style="color: black;">I've never tried to do this, but
the only way I could think to do this is using HSRP on the FE interface. this
is assuming that the HSRP address can be used as the source-address for the CME
system. <br>
<br>
This would make proper documentation and config sync a critical process though.
<br>
<br>
<br>
<br>
On Jul 12, 2009 3:03pm, "Bill Greenwood (US)"
<bill.greenwood@us.didata.com> wrote: <br>
<br>
> <br>
> <br>
> I am looking for information on how to provide redundancy for a CME based
system. <br>
> The configuration is there are two identical routers at the <br>
> site, two PRI circuits to the PSTN and 60 or so phones. I am at a
loss as <br>
> to how to recommend redundancy for this. Is it one router configured
with <br>
> CME as normal, but how should the second router be configured? Is
the <br>
> second router configured with CME or as an SRST router. How should
the <br>
> second router appear to the primary CME router? How should the PRIs
be <br>
> connected, if one is connected to each router I can set up the dial peer
to <br>
> route the outbound calls, but how are the inbound (from the PSTN)
routed? <br>
> If the PRIs are connected to only one router redundancy is lost. I
have <br>
> be unable to locate any documentation that explains how to set this up. <br>
<br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> Thanks for your help. <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> Bill <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> Disclaimer: <br>
> <br>
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