asterisk users - Jan 2005 - Asterisk in a mixed phone environment

Hi,
    How difficult is to setup and maintain an Asterisk PBX with phones from
multiple vendors? Is it even worth considering or is it safer to pick one
vendor for phones and stick with them? I am more concerned about proprietary
DHCP extensions, firmware upgrades etc..If anyone has any thoughts or
experiences they would like to share I would be more than happy to hear from
them.

Thanks

-Ravi Ramamirtham

> Hi,
>    How difficult is to setup and maintain an Asterisk PBX with phones from
> multiple vendors? Is it even worth considering or is it safer to pick one
> vendor for phones and stick with them? I am more concerned about 
> proprietary
> DHCP extensions, firmware upgrades etc..If anyone has any thoughts or
> experiences they would like to share I would be more than happy to hear 
> from
> them.

Having implemented quite a few mixed and non mixed vendor systems, my two 
cents is to stick with one vendor especially in a production environment. 
Here are my main reasons.

1) Standardization of features: If all the phones have the same feature set, 
there is less of a fear of incompatibility between endpoints.  While you can 
minimize this though careful configuration and dialplans, for large systems, 
you need to almost be God to think of everything.  At least with one vendor, 
you know a set of features to work with that will work across the board.

2) Easier Configuration and Maintenance: Pick one vendor type, be it SNOM, 
Cisco or others and you now only have one type of configuration file to 
maintain.  Most vendors solutions can be configured TFTP so you can create 
configuration templates that will work across all the phones with only minor 
modifications.  I have currently been recommending to people the SNOM phones 
for the simplest rollout of a large number of phones.  They support config 
files via HTTP.  More specifically, you can use a scripting language to 
generate the config files on the fly from a database.  If you setup a 
database driven asterisk config, this essentially would ELIMINATE any 
individual file maintenance but it requires a single vendor, in this case 
SNOM, to work (BTW, for anyone who is interested, I hope to be releasing the 
fully dynamic phone code within the next few months once I actually have the 
time to sit down and fully write it)

3) Simpler troubleshooting:  I'd hate to count the number of SIP traces I 
have had to do to figure out if a problem I was having was one endpoint, 
asterisk, or another endpoint.  Having phones from the same vendor usually 
removes a step in the whole process.

4) Price:  Buy more phones from one vendor, and you are likely to get a 
better price.  By the time you are done combining high end desk phones and 
lower end phones, you might have been able to get a better bulk price on the 
higher end phones thus negating any cost savings by going with lower end 
phones.

5) TCO: All of these reasons are likely to lead to a system that costs lower 
to maintain long term.  Remember, you can buy a really cheap car and add a 
whole bunch of third party options, but if one of those options fails, you 
have to remember who installed it, deal with varying degrees of support, and 
mostly spend more time figuring out who is going to resolve the problem 
rather than getting the problem resolved.  The same occurs in most IT and 
Telecommunications installations.  Having too many vendors in the pot tends 
to lead to the "its not our problem" syndrome I think we have all 
experienced one time or another.  Remember that there is more cost to any 
system than what you pay upfront for it.

With that said, the choice of the vendor for the system is especially 
critical.  Is this vendor going to be in business next week? Do they provide 
the level of support you need?  (Maybe you don't need any support, maybe you
need high level support.  Is that level available to you?)  Does the vendor 
have a long term plan for integration with Asterisk?  These are some tough 
questions and will vary based on your needs for future flexibility and 
upgradeability.

With any luck, I'm hoping to have some time soon to write another article 
similar to http://voip-info.org/wiki-Asterisk+setup+soho+4+CO+12+extensions 
describing a low maintenance, and high reliability system config 
recommendation for a VoIP setup.  (BTW, thanks to all who have written me 
thanking me for the clear recommendations)


Raymond McKay
President
RAYNET Technologies LLC
http://www.raynettech.com
(860) 693-2226 x 31
Toll Free (877) 693-2226