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tschafferx
Beginner

Question: Redundancy with Local Route Groups

Hello Cisco community,

 

I was wondering, how a redundancy could be set up with the use of LRGs. How would I configure the following scenario with LRGs:

 

1 Route Pattern -- 1 Route List containing 2 individual RGs --- RG 1 IP-WAN - RG 2 PSTN (Failover) -- Devices

 

With LRGs I can only assign 1 RG at the Device Pool level. What if the devices in that RG go down and I want to provide a backup path over the PSTN.

 

Thank you in advance.

 

Any help is appreciated.

1 ACCEPTED SOLUTION

Accepted Solutions
Nipun Singh Raghav
Cisco Employee

You would leverage the route list for redundancy in this case -

RL -
Standard Local Route Group (1st Preference)
PSTN-RG (2nd Preference)

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

View solution in original post

8 REPLIES 8
Nipun Singh Raghav
Cisco Employee

You would leverage the route list for redundancy in this case -

RL -
Standard Local Route Group (1st Preference)
PSTN-RG (2nd Preference)

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

View solution in original post

Thank you for the reply. Okay, then it's important to set the distribution algorithm to Top Down. I guess that with LRGs load sharing via a circular approach would not be feasible. Correct?

There is no algorithm in a route list that you can configure on CUCM. Distribution algo is there for RG.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

Thank you for the quick reply.

I am aware of that. But there is for Route Groups and if I wanted to achieve some sort of load balancing with LRGs I would have to set the distribution algorithm (within the respective Route list) to circular, which in turn would invalidate the design for redundancy.

Not sure if I understand you but per your requirement you were looking for a way to provide redundancy when using LRG which I highlighted that can be done within the RL itself. Now for example the PSTN-RG that I have mentioned above have multiple gateways/trunks etc, yes the distribution algorithm will come into picture which will only come into effect if the SLRG is not able to route the call/fails.

With the RL redundancy you aren't invalidating anything. Again, distribution is not within the RL but its something that is within the RG.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

The first part is clear. You mentioned that redundancy can be achieved by placing several devices into the LRG. That's understood. What I did now is to compare it to the old approach with RL -- RG -- Devices where I could have several RGs under 1 RL with different purposes. So let's say that RG 1 is assigned to 2 GWs that have a circular distribution algorithm to achieve load balancing over the two GWs. RG 2 is assigned to a SIP-Trunk that I want to use, in case the 2 Gas go down. CUCM would see that within the RL there are two RGs selected by priority. 1st RG goes down it would automatically switch to the 2nd RG. 

 

Now I thought about a deployment to copy that behavior with LRGs. What I have seen is that with LRGs you can only specify 1 Route Group with various devices but not opposed to the 'traditional' approach several RGs inside a single RL.

 

I hope that makes it more clear. :)

Understood and your are correct but there with a close mimic to what you are trying to achieve would be what I have explained in my initial post.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"

Okay, got it. :) Thank you! I was totally focused on LRG and thought you mean the 1 route list within the LRG scenario... That's what confused me, I couldn't see where the two RGs would be placed within the LRG configuration. The reason for posting the question was to find out, if there's maybe a way to achieve the described that I haven't been aware of yet.

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