Practical use question - cme or cme to cucm over vpn tunnel?

JeanM

Hi, while playing around with some lab routers and internal dial peers I was wondering if it would be of practical use to let's say add ipsec vpn to a pair of 2620xm routers with voice-2v / fxs for a remote "office" to "home/office" scenario?

Then maybe even add cucm running on esxi host to the mix as the master call manager, and have the two CME running routers vpn over the internet as two "branch" offices?

Just trying to put these to some practical use, you can only do so much w/o adding or running things over the net or from/to remote locations, might as well make it fun?

Jollycork

Sure...why not.... at least you'll know how to do it...

in practical use terms though, I don't know many large businesses that run Callmanager that stick CME at a bunch of remote sites they have, so those at remote sites can just dial by extension number.

I've only run across CME at less than a hand full of sites...actually it was only 1...and that was at a chain shoe store. ..and then they had only 1 IP phone at the store to call to corporate over IP. The rest POTS.... "and that"...was 6 years ago... today, I still see mostly POTS at small businesses... even franchise stores of big chains, the stores themselves use POTS...

JeanM

Jollycork wrote: »

Sure...why not.... at least you'll know how to do it...

in practical use terms though, I don't know many large businesses that run Callmanager that stick CME at a bunch of remote sites they have, so those at remote sites can just dial by extension number.

I've only run across CME at less than a hand full of sites...actually it was only 1...and that was at a chain shoe store. ..and then they had only 1 IP phone at the store to call to corporate over IP. The rest POTS.... "and that"...was 6 years ago... today, I still see mostly POTS at small businesses... even franchise stores of big chains, the stores themselves use POTS...

Do you see that branch or remote offices run their own cucm or don't run any at all and use just pots?

shodown

I'm on my phone right now, but I'll give a few examples and elaborate more when I get home if anyone is interested.


1. Large manufacturing company kept loosing circuits in overseas location. Each time they went down they were down for 4 to 5 days min
One time this happens during end of quarter closeouts. The phone bill was 5 times the cost of cme/cue licensing. We moved them over to cme with backup over ip sec in cause they wanted to dial any other site.


2. One company did quite a few office moves. It was a hassle to always change stuff for them. They got the there own cme that could change on the fly to meet there changing requirements

Alex90

I be interested to see how to this - is it possible on CUCM v6?

This is what we're currently using.

JeanM

shodown - please do

I was thinking that a backup route (vpn or not) or PSTN (but costly as in your example right?) as backup would be a way to go vs. having the RTP go all way over WAN link to the main office call manager vs. having your own branch call manager/cme and then route to main office as needed. Plus, that way if the main CM goes down or WAN link is lost, then at least local branch calls aren't affected.

Alex90

I certainly remember Jeremy Ciora demonstrating an example where the PSTN is used as a back up if the WAN goes down.

shodown

Business requirements drive what you should do for your VoIP system. There are tons of ways to design the system and its really hard to give good guidelines without knowing the business functions. I made a post a while back about a fairly large company only have a a few pri circuits and that fit there business, and I had another company that had way less people, but double the capacity cause damn near 90 percent of that company was on the phone at all times. The phones were there money makers so telling them they needed dual routers, and multiple paths in and out was no big deal for them.



Are there any specific questions, or anything you want to ask what I have seen. I have seen quite a bit as I've spent the majority of my VoIP career at VAR's then my own shop.

JeanM

shodown - how about just some simple examples.

a. HQ and remote Branch Office (would you go with CUCM on both ends, or CME configured as SRST, over wan/vpn?) located in same state/country
b. HQ and three remote branch offices , one branch office located in another country. (I imagine, you would not want to use PSTN for backup here at all)/

Maybe you could share the common configuration or two, and pro/cons?

shodown

Good questions.1


1. It depends on the business and the branch office. Usually I would put the CUCM at the HQ if there is a decent Data center there, if not it would go in to there data center at another site and both sites would connect to it over MPLS. Some questions to ask. If you have a branch office with more than 300 people would you have CME with SRST? That's a huge loss of functionality if they went down. You could cluster your CUCM over the WAN, but then have the latency requirements to meet of that design, you could build another CUCM cluster which has its own problems. These are all design questions you have to work out with the customer when building. Sometimes presales will get this all figured out, and other times you will have to think this all through.


For questions 2(b) they are pretty much the same answers.


The most common design is CUCM at HQ and SRST routers at branch sites. There is usually no need for CME SRST unless there is some sort of extra functionality needed.




Cisco Collaboration System 10.x Solution Reference Network Designs (SRND) - Cisco


This document is your bible. I read from it everyday. If you guys to decide to make voice your primary focus reading this becomes a must.

Alex90

Thanks for the response shodown.

So could you potentially have something like this: CUCM cluster at the HQ, 1 PUB & 2 SUB connecting to a L3 switch which uses a DWDM .1q trunk across to another L3 switch at a remote site? At the remote site you'd have possibly another 2 SUB's which could be part of the same cluster? Could you then connect to the L3 switches 2 voice gateways with PRI's connecting to the PSTN?

Could something like that work?

shodown

yeah that would work, but depending on the size of the sites that could be overkill, but you could do it. CUCM licencing is damn free now. You can build as many CUCM's as you would like as long as you have the hardware to support it. You pay for user licencing now.

Alex90

Ok understood.

I know what you mean about the user licensing - we've been slowly replacing all our analogue conf phones with the polycom soundstation 7000. You have to add it to CUCM as an third-party SIP device (advanced) which takes up 6 licenses alone!!!

We're always in minus figures with our available licenses but luckily you get 5% extra to play with on CUCM.

JeanM

shodown - thanks! I was watching some udemy ccna voice training courses last night and David Bombal referenced SRND as well . I picked up older Cvoice/CIPT1 and CIPT2 books (as they were really cheap) and was just scanning through them, they have some good examples as well that helps put things into clear ideas.

Appreciate your posts!

shodown

in CUCM 9x they introduced the ELM, which means you won't have the extra 5 percent anymore. Cisco will continue to let you add phones, but you get 60 days to get correct licencing in the system. If you don't your system will lock up and you wont' be able to make any changes on the CUCM side. On the unity connection side voicemail will ring fast busy until someone buys more licences or deletes the users in the system.

Alex90

Thanks, thats useful to know actually. We're still on CUCM 6.1 so we're in the process of trying to get a plan together to upgrade to 9.x or 10.x. Our voice recording solution was upgraded two months ago so I can't see us getting approval for the cost until middle of 2015 at the earliest. Am I right in think that to move from CUCM 6 to 10 you would have to do it in a 2 set upgrade? For example CUCM 6 to 8 then 8 to 10?

shodown

You maybe better off just doing a fork lift upgrade. Since you would have to purchase new hardware I would just make a 10.5 or 11.x server and import all the people into the new box with a new dial plan and all the new features. It would be painful for a while, but no since in taking a system built in 2008 time frame when you can have a 2015 system that takes advantage of all the newer features. This is a hard sell to management, but more than likely would be the best way to get the best performance. Other wise depending on what version of 6 you are on you will have to

1. Upgrade to a version of 6 that can upgrade to 9x, then upgrade from 9x to 10x/11x. That requires lots of backup's and restores then a flash cut over to the new system. The benefits is that you can get all of the work done during the day, then only have the night to cut over. The downside is any bad configuration comes over to the new system so any lingering problems will follow you.

You can also do a hybrid approach. Do the backup's and restores and slowly add new features and test them. Then cut over completely to the new system. This has the most risk as 100 percent something will not work as before and people will complain.