I see many posts about issues regarding problems with CallManager. I am looking at switching my company over to a CallManager environment. My question is, with all these issues that come up from time to time(and I know every install in different and I may never see any of these problems) has anyone had a CallManager setup just flat out stop working? My budget is only big enough right now for one CM server with another one very late in the year. The little glitches can be resolved but I will catch you-know-what if the phone system goes down across the board.
How many phones do you need up - in an emergency....
I'd suggest you think about an SRST deployment initially - and then a pub-subscriber cluster when budget allows.....
SRST is a fairly low cost IOS feature set.
About 25 phones is the total and we need all up. I looked at SRST but that seems geared more toward the WAN calls coming into the CallManager. I am looking at making CallManager my PBX since my current Key system is out-dated, at capacity, can't be upgraded and I am rolling out CallManager anyway.
SRST is generally used for WAN backup - but it can be used for local backup - until that time when budget will allow another call manager server.
It somewhat depends upon what gateway you need - i.e. if you already have a router - 2620 would support 24 phones/48 LA...
CM is very stable - if setup correctly - what you read here are many different configurations - some with exisiting eq. - rather than all green field installs....
I am focusing my career on VoIP. I want to be the a guru when it is all said and done. Ten years in traditional voice and 3 years in data only 2 on Cisco has taught me one thing. Set up a test lab throw some volume on it and wait and see. I have hundreds of users on the call manager worksgreat most of the time. Remember all most users want is dial tone and some times Call Manager will not give you that. Five nines go out the window with VoIP,VoFR, ect. Just try it first and know you will spend 90% of your time working on it. Stick with it one day it will make us all better engineers.Hope my rambling helped. Be careful.
I have several clients using CCM and have not yet seen one "just flat out stop working". Most issues I have come across were the result of inadequate planning, unrealistic expectations, or were flukes that could not be predicted.
Call Manager is a fine product, but VoIP technology is still "green". As dconstantino said, five nines (99.999 percent uptime) is out the window. CCM is built on a hardened Windows platform - the most crash-prone OS I have used. If the system crashes hard, it could require a complete reload and reconfig - which can take hours. So the first question you should be asking is, "how critical is this phone system to my business and my users?"
For those of us from a data background, the configuration is not intuitive (for any voice product, and CCM has a much better interface than comparable products from Nortel and 3Com). It will require considerable planning (CCO has some very good planning tools for this) or you WILL have problems implementing the technology. So the second question you should ask is, "do we have the resources, or have we planned to spend enough to pay someone with the experience, to make this work, work right, and work the first time?" (People are so unforgiving where their phones are concerned.)
Current VoIP soft-PBX systems do not include all the functionality of a traditional PBX. You may need Unity or other products to get all of the functionality your users are used to. Third question: have you done a feature-for-feature comparison of "hard" and "soft" PBX products - and matched them against the expectations of your users?
I work with VoIP solutions and do not want to discourage you if this is a good fit for your company, but I have seen people move to this technology with unrealistic expectations. They have been disappointed because the technology did not meet those expectations - or more often, they did a poor job of planning and implementing the product.
You may want to investigate the laws in your area regarding e911 and the solutions Cisco suggest for this thorny issue.
If you decide to use CCM, I urge you to use one of the power-over-Ethernet options to power the phones so that you can throw a UPS on it and not loose the phones in a black- or brown-out. Have you seen the Cisco ICS7750 product? An all-in-one shelf-based product, it provides more fault-tolerance than the stand-alone version of CCM, and is expandable and cost-efficient as your budget allows you to grow the system (build in redundancy).
Thanks guys for your input. It was truly invaluable. We are a smaller company and can't stand the down time surrounding a soft PBX. Our current PBX is about to be replaced and I thought "Hey...well since we are rolling this out anyway....". I really appreciate the insight. The reason for CallManager in the first place is for Voip for some remote users. about 6 in total. I am planing on connecting CallManager and the PBX and using CallManager for the Voip Calls and not as our PBX. For these users the phone is not as important but I will still catch it if they are down alot. Any thoughts on this setup?
The same cautions we were discussing before apply here for the remote users. Are the users all in a branch office? If so, you could drop the CCM into the remote office and run a WAN link back to a gateway into your PBX. If they are in homes offices, it becomes more complex - a gateway to the PBX instead of the trunks to the PSTN, use of a VPN to get them into the local net(?), QoS questions, compression codex.
How remote are the users? If they are in the same LATA, you might check on the availability of Centrex. Centrex is a Central Office service that will allow remote sites to operate as if they are directly attached - even using "local" extention numbers. Check with your phone provider for availability.
4 users in 4 locations 2 different states that work from home. No branch office at all. Maybe I could implement SRST like John suggested earlier but not for the central site , for these remote users instead so that if CallManager goes down they can still get and make calls. Or at least that is my limited understanding of SRST. Anybody know if thats what it can do? John?
How are these users connected to your main site...if you like - you can email me drawings, etc.
I tend to doubt that SRST will be the appropriate choice for these users - because you will probably have a 1FB analog line anyway - so they could just use a backup phone/fax machine in a "down" situation - but....
SRST can work very well - I did an install in AZ - and the frame-relay provider messed up - and I was glad we had pre-configured the phones - they "booted" up just fine to the router - and users used them for 2 days until the frame circuit was up.
I just got off the phone with Cisco pre-sales and they say that SRST is not a fit for my needs. The users are work-from-home people in different states and will have 1 IP Phone per site connecting back to CallManager at a central site but not stopping there. They will be connected to my PBX from that point so that they can have extensions at the remote sites and do toll-bypass when they talk to central and central to them etc. They will be coming in over a 128 kbps VPN connection to a VG200 gateway. Yes I already know about lack of QoS over the Internet and other shortcomings in doing VoIP over the Internet but I believe I have the best possible situation for this. Remote users are using the same Tier 1 ISP as the central site with a guaranteed 1 hop count back to the central site and SLA for latency under 65ms. I was hoping that somehow SRST could get these users connected back to the cental site with the usage of extensions intact until CallManager came back up. Pre-sales said SRST was more for branch office types deals to allows the router on-site to act as a "mini-CallManager" and that it could not get these users connected in the manner that I need. Your thoughts John? Or anybody in a similar circumstance?
I am still thinking that SRST could be used - while it wasn't really designed for what you are suggesting - with say a 3002 connected to a 3015 (vpn)- the phone could for all practical argument - reside on the central site network. The VG200 will not support SRST - as it is not a router - you could use a 2620 instead of the VG200 - I am not suggesting that you put SRST routers at the remote sites - just vpn into the central SRST router.
Did they give you a specific reason why it would not work - ??
BTW - This is a somewhat hypothetical solution - I should have a better idea of if this possible Thur. eve.
You may want to consider one of the firms that host the CallManager - typically, they have the redundant infrastructure to satisfy your concerns regarding outages, etc and can offer terrific rates for termination - in addition to being rather intimate with the platform.... www.appiacomm.com
Hey John, I basically have to use the VG200 for transcoding and allowing conferencing at a lower bandwidth consumption. Right now my plan is a 3002 coming into a 3005 with the PC and IP Phone plugged into the 8 port 3002. I can throw a 1751 in there instead of the 3002 but if I am coming in on a 3005 for VPN and then voice calls going into the VG200 is there a way to make the IP phone fail-over to the 2600 that will be using SRST as the voice gateway should Call Manager go down?