The Microsoft solution, when all the pieces are integrated, is sexy. Taking a page from the Apple book, Microsoft has implemented the "gee-wiz" features that demo to customers very well. Be it the text-to-speech e-mail engine, the voice recognition Auto Attendant of Exchange Unified Messaging, or the tight integration of Live Meeting with other Microsoft applications, the Microsoft solutions shout "hip" and "snazzy." (Two videos on the Microsoft Web site, based on the rather dreadful movie "The Devil Wears Prada," showcase this perfectly.)

But for all the hype and jazz, the Microsoft solution falls short on a number of issues that are going to be important to larger enterprises. While taking care of the sex and sizzle, Microsoft has forgotten the fundamentals that make these technologies work. Basic features such as music-on-hold is slated for future releases, and even the venerable call-parking is not a feature currently supported. The core routing rules, such as which trunk to use when routing to emergency calls or how to use site access codes for overlapping extensions, are also very limited in flexibility on the Microsoft platform. Finally, the list of supported VoIP gateways is laughable, with none of the major vendors currently supported.

However, while these oversights might give Cisco and its partners some comfort, they are small and short lived when you consider the factors going Microsoft's way. Microsoft has a loyal troop base of MCSE's and other server experts chomping at the bit for a chance to roll out VoIP their way, with the software and the servers providing the intelligence and the network simply delivering the packets. No new Call Manager interfaces to learn, no separate directories to take care of, and familiar Microsoft products and jargon is nirvana to the Microsoft Administrator.

However, a lack of understanding of the importance of QoS in a converged network, and failure to understand the many finicky aspects of the PSTN, will doom many overzealous Microsoft administrators. A criticism often directed against Cisco VoIP engineers is their lack of understanding of the traditional PSTN and PBX technologies. With Microsoft administrators lacking understanding of the IP network as well the PSTN, this criticism will (pardon the pun) ring true.

The aftermath

The Microsoft IP telephony solution is still in its infancy but already shows the telltale signs of a bright kid. If Microsoft is smart enough to send it to the right schools it will grow up to do great things. For the here-and-now, Cisco has little to fear from Microsoft in large enterprises and the Microsoft reputation is a two-way street: While the company obviously has strong brand recognition, many large enterprises will be less than inclined to trust such a critical corporate function to a company with a less-than-enviable reputation for software quality.

The best bet at the moment is the use of both Microsoft and Cisco technologies. The use of Exchange 2007 for voicemail with a Call Manager is a no-brainer. Most enterprises currently run Exchange, and integrating Call Manager effectively is a snap. Smart channel partners that resell both Microsoft and Cisco will use this as an opportunity to push Exchange 2007 upgrades by touting the virtue of unified messaging when integrated with Call Manager.

The Cisco presence vs. Microsoft presence argument is going to come down to money: In order for Microsoft OCS clients to be able to "see" the on-hook/off-hook status of Cisco IP phones, you need a Cisco Presence server. This means doubling-up on licensing and many enterprises may opt to use the Cisco Presence client. Finally the Microsoft Live Meeting product is too tightly integrated into OCS at the moment to be a viable Cisco MeetingPlace alternative for current Call Manager users.

I have come to the conclusion that, as is usual in warfare, there is more grey than black and white. Both the Microsoft and Cisco solutions have there merits and downfalls.

For those in the trenches trying to sort all of this out, my advice is to become an expert in the technologies involved, rather than becoming a slave to any one vendor. For example, learn SIP forwards and backwards so you can debug your Ethereal packet captures to work out why OCS will not talk to Cisco Presence (I confess that I have poured over SIP output for a good four hours before finally sorting out all the integration gremlins). And learn why QoS is important, understand the different codecs available and their distinct advantages/disadvantages, but most of all, don't forget that until the PSTN dies, you are still going to need to integrate with it. A thorough understanding of ISDN, FXO, FXS and myriad of other considerations when connecting to the PSTN will serve you well.

Peter John Revill is the Senior network engineer at a Perth, Australian-based Cisco VoIP Partner. He has been working in computing for 7+ years and specifically in the VoIP/IP telephony field for the past three. He holds a CCIE in Routing and Switching (#18371) and has his CCIE voice lab booked for March 2008. He can be contacted at nervlord@westnet.net.au. The views in this article are Revill's and may not represent those of his employer.