[cisco-voip] Redundancy Options for CME

[Nick Matthews]

The primary configuration is:

telephony-service
ip source-address <cme1> secondary <cme2>

You configure this same thing on both routers.

Then, you configure the h323 dial peers as discussed for routing the
PRIs when a call comes into the secondary CME.


-nick



On Sun, Jul 12, 2009 at 4:31 PM, Lelio Fulgenzi<lelio at uoguelph.ca> wrote:
> 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.
>
> 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.
>
> 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. ;)
>
> 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). ;)
>
>
>
>
>
> ---
> Lelio Fulgenzi, B.A.
> Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
> (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> "Bad grammar makes me [sic]" - Tshirt
>
>
> ----- Original Message -----
> From: "Bill Greenwood (US)" <bill.greenwood at us.didata.com>
> To: cisco-voip at puck.nether.net
> Sent: Sunday, July 12, 2009 4:20:02 PM GMT -05:00 US/Canada Eastern
> Subject: Re: [cisco-voip] Redundancy Options for CME
>
> Thinking more about this:
>
>
>
> 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?
>
>
>
> Bill
>
>
>
> From: Lelio Fulgenzi [mailto:lelio at uoguelph.ca]
> Sent: Sunday, July 12, 2009 4:03 PM
> To: Bill Greenwood (US)
> Cc: cisco-voip at puck.nether.net
> Subject: Re: [cisco-voip] Redundancy Options for CME
>
>
>
> 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.
>
> 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.
>
> Here's a press release talking about it (in very general terms).
>
> http://www.cisco.com/en/US/prod/collateral/routers/ps5854/prod_case_study0900aecd80424090_ns431_Networking_Solutions_Case_Study.html
>
>
> ---
> Lelio Fulgenzi, B.A.
> Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
> (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> "Bad grammar makes me [sic]" - Tshirt
>
>
> ----- Original Message -----
> From: "Bill Greenwood (US)" <bill.greenwood at us.didata.com>
> To: cisco-voip at puck.nether.net
> Sent: Sunday, July 12, 2009 3:43:39 PM GMT -05:00 US/Canada Eastern
> Subject: Re: [cisco-voip] Redundancy Options for CME
>
>
> 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.
>
>
>
> From: mthompson729 at gmail.com [mailto:mthompson729 at gmail.com]
> Sent: Sunday, July 12, 2009 3:11 PM
> To: Bill Greenwood (US)
> Subject: Re: [cisco-voip] Redundancy Options for CME
>
>
>
> 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.
>
> This would make proper documentation and config sync a critical process
> though.
>
>
>
> On Jul 12, 2009 3:03pm, "Bill Greenwood (US)" <bill.greenwood at us.didata.com>
> wrote:
>
>>
>>
>> I am looking for information on how to provide redundancy for a CME based
>> system.
>> The configuration is there are two identical routers at the
>> site, two PRI circuits to the PSTN and 60 or so phones.  I am at a loss as
>> to how to recommend redundancy for this.  Is it one router configured with
>> CME as normal, but how should the second router be configured?  Is the
>> second router configured with CME or as an SRST router.  How should the
>> second router appear to the primary CME router?  How should the PRIs be
>> connected, if one is connected to each router I can set up the dial peer
>> to
>> route the outbound calls, but how are the inbound (from the PSTN) routed?
>> If the PRIs are connected to only one router redundancy is lost.  I have
>> be unable to locate any documentation that explains how to set this up.
>
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>>
>> Thanks for your help.
>>
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>> Bill
>>
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