DiVitas partners with Avaya

Last week Avaya announced that it has chosen DiVitas as its preferred partner for mobile unified communications (UC). The companies will do joint marketing and cross-training of their sales forces in a reference sale mode. This is huge for DiVitas because it opens Avaya’s distribution channel to it. According to Phil Klotzkin, Avaya’s senior manager for UC, this channel supplies 20% of the business phone systems world-wide.

The DiVitas solution plugs a small but important gap in Avaya’s product line. Avaya already has a mobile unified communications solution, called one-X Mobile.

One-X Mobile extends PBX features to cell phones, notably the ability to give out a single number that rings on both your cell phone and your desk phone; the ability to do PBX-related actions like 4 digit dialing and transfers; visual voicemail; and the ability to move a call in progress between the cell-phone and the desk phone.

The DiVitas product offers a comparable solution set, but goes beyond one-X Mobile with Wi-Fi voice and a range of social networking features including IM and Presence. Because it uses Wi-Fi, the DiVitas solution requires a dual-mode handset. Virtually all new smartphones are dual-mode, but with the exception of Nokia’s Eseries and Nseries, few of them are well suited to voice over Wi-Fi. One-X Mobile uses the cellular voice channel rather than Wi-Fi, so it runs on a wide variety of phones.

For IM related features both DiVitas and Avaya’s desktop Integrated Presence Server use open source Jabber software. The two will be integrated with each other by the end of the year.

DiVitas/Avaya system diagram

For now the DiVitas handset software (client) is not integrated with the one-X Mobile handset software – the customer will choose one or the other for each user. The DiVitas client and the one-X Mobile client will each retain their different look and feel, and the one-X Mobile client will continue to run on single-mode phones and the DiVitas client on dual-mode.

In a recent interview, Klotzkin said that one-X Mobile is sufficient for most customers, but that there are a few for which dual-mode functionality is essential. Partnering with DiVitas enables Avaya to satisfy those customer needs. One such customer is CSX, the freight company. Some of its far-flung operations are in areas with no cellular coverage; Wi-Fi solves this problem. Avaya has been working with CSX on dual-mode solutions since 2004, when Avaya, Motorola and Proxim introduced the very first dual-mode system.

According to Vivek Khuller, CEO of DiVitas, “CSX has been working with Avaya since the earliest days of dual-mode telephony, and they are finally satisfied. It’s an important accomplishment for both our companies.”

Because the DiVitas solution uses smart-phones CSX gets a useful side benefit, namely that it can run proprietary application software on the phones, eliminating the need for its employees to carry a laptop. The other side benefit is that even in areas of cellular coverage the Wi-Fi connection can be used to save on cellular minutes.

So everybody gains. Avaya plugs a troublesome gap in its product line; DiVitas gets an excellent distribution channel; the Avaya channel adds a fully supported best-of-breed solution to its portfolio; and end users get the familiarity of Avaya with the handset technology of Nokia and the DiVitas software that weaves them together into a user-friendly package.

A not so perfect Storm

The Verizon Storm may be heading for failure in more than one way. A raft of reviewers, led by David Pogue of the New York Times are trashing its usability. This means that even with the marketing might of Verizon behind it it may not fulfill its goal of being a bulwark against the iPhone in the enterprise.

But the Storm was an experiment in another way by Verizon. The other three major American mobile network operators have capitulated to Wi-Fi in smartphones. Against the new conventional wisdom, Verizon decided to launch a new flagship smartphone without Wi-Fi. The Storm looks like a trial balloon to see whether Wi-Fi is optional in modern smartphones. If the Storm is a success, it will demonstrate that it is possible to have credible business smartphones without Wi-Fi. But if it turns out to be a flop because of other factors, it will not be a proof point for Wi-Fi either way.

But Wi-Fi is a closed issue by now for all the network operators, perhaps even including Verizon. Phones have lead times of the order of a year or so, and controversies active back then may now be resolved. Verizon covered its bets by launching three other smartphones around the same time as the Storm, all with Wi-Fi (HTC Touch Pro, Samsung Omnia, Samsung Saga).

Before its launch, AT&T hoped that the iPhone would stimulate use of the cellular data network. It succeeded in this, so far beyond AT&T’s hopes that it revealed a potential problem with the concept of 3G (and 4G) data. The network slows to a crawl if enough subscribers use data intensively in small areas like airports and conferences. Mobile network operators used to fear that if phones had Wi-Fi subscribers would use it instead of the cellular data network, causing a revenue leak. AT&T solved that problem with the iPhone by making a subscription to the data service obligatory. T-Mobile followed suit with the Google phone. So no revenue leak. With the data subscription in hand, Wi-Fi is a good thing for the network operators because it offloads the 3G network. In residences and businesses all the data that goes through Wi-Fi is a reduction in the potential load on the network. In other words, a savings in infrastructure investment, which translates to profit. This may be some of the thinking behind AT&T’s recent acquisition of Wayport. The bandwidth acquired with Wayport offloads the AT&T network relatively cheaply. AT&T’s enthusiasm for Wi-Fi is such that it is selling some new Wi-Fi phones without requiring a data subscription.

The enterprise market is one that mobile network operators have long neglected. It is small relative to the consumer market, and harder to fit into a one-size-fits-all model. Even so, in these times of scraping for revenue in every corner, and with the steady rise of the Blackberry, the network operators are taking a serious look at the enterprise market.

The device manufacturers are way ahead of the network operators on this issue: the iPhone now comes with a lot of enterprise readiness Kool-Aid; Windows Mobile makes manageability representations, as does Nokia with its Eseries handsets. RIM, the current king of the enterprise smartphone vendors also pitches its IT-friendliness.

Wi-Fi in smartphones has benefits and drawbacks for enterprises. One benefit is that you have another smart device on the corporate LAN to enhance productivity. A drawback is that you have another smart device on the corporate LAN ripe for viruses and other security breaches. But that issue is mitigated to some extent if smartphones don’t have Wi-Fi. So it’s arguable that the Storm may be more enterprise-friendly as a result of its lack of Wi-Fi. Again, if the Storm becomes a hit in enterprises that argument will turn out to hold water. If the Storm is a flop for other reasons, we still won’t know, and it will have failed as a trial balloon for Wi-Fi-less enterprise smartphones.

DiVitas Test Drive

Divitas loaned me a Nokia E71 to try out with their mobile unified communications solution hosted by Sawtel. It’s a very nice phone – looks good, feels good in the hand. It’s also the best-sounding cell phone experience I have ever had, and that’s thanks to DiVitas. All cellular service providers use technology that sacrifices sound quality for increased carrying capacity. By squeezing down the bandwidth used by a call they can fit more calls into each cell, and get by with fewer cell towers, saving money. The standard codec around most of the world is GSM, and it’s the reason that cell calls can never sound as good as landline calls.

But DiVitas uses a Wi-Fi connection for your calls, and they have chosen to use the standard land-line codec, G.711. The effect is startling – a little disorienting even; we are so used to the horrible GSM codec that when a cell phone sounds as good as a land-line the subjective illusion is that it sounds much better.

This is one of the reasons that the type of voice over Wi-Fi solution offered by DiVitas is way better than the one offered by the telco industry, called UMA. UMA uses the GSM codec even over Wi-Fi connections.

But DiVitas didn’t stop with the sound quality. DiVitas has done an excellent job in several other technical areas. The fundamental technology of fixed mobile convergence is the ability to hand off a call in progress from the cellular network to the Wi-Fi network and vice versa.

This is very challenging, and it is an area where DiVitas claims to lead. So the first thing I did after turning on the phone was to make a call to check it out. I didn’t need to look at the on-screen indicator to know that the call was running over my office Wi-Fi network. The sound quality (did I mention this before?) was superb. So I walked out of range of the WLAN and sure enough the call handed over to the cellular network without dropping. There was a brief interlude of music and the call continued. Going back into the WLAN coverage area the handoff was completely seamless, perceptible only by the improvement in call quality as it moved from the cellular to the WLAN network.

Superior sound quality and seamless handover, while impressive to an engineer who knows what’s entailed, are not really sexy to regular users – it’s just a phone behaving like you would expect. DiVitas takes it to the next level by overcoming another technical challenge, delivering a polished, well thought-through, feature rich and well integrated user interface on the phone.

Actually, the DiVitas software client for the handset overcomes two challenges. The technical challenge of integration with the phone’s native software environment, and the design challenges of usability and usefulness. User interfaces are a matter of personal taste; the best are those that don’t get in the way of doing what you want. I disappointed the people at DiVitas by discarding their carefully written instructions and forging ahead by trial and error. Considering the potential consequences of this behavior I got away lightly. Everything worked the way I expected it to, and there were some nice touches, including Skype-like presence icons by the names in the directory.
While we’re on the topic of the directory, one thing that jumps out is the four digit phone numbers.

This is an indicator of yet another set of technical challenges that DiVitas has overcome to deliver their solution, namely integration with the corporate PBX, and presentation of the PBX features through the cell-phone user interface. DiVitas users will actually get a superior experience of the PBX through their cell phone compared to their desk phone. This is because the DiVitas software has a computer industry heritage rather than a telco heritage; it takes advantage of the nice big color screen with features like the presence icons and voice mail presented in an on-screen list like on the iPhone.

So the big news here is that a product has finally caught up with the hype around enterprise Mobile Unified Communications. All my criticisms (DiVitas got an earful) are nitpicking. For me the system worked as advertised, and that’s saying a lot.

Femtocell versus Wi-Fi

Rethink Research has published an interesting article relating the new Wi-Fi voice certification to the outlook for femtocells.

The idea of the article is that voice over Wi-Fi for cell phones is competing with femtocells, and that femtocells may win out. The article distinguishes between business voice and consumer voice, saying that service providers see femtocells as “an important stalking horse for greater control of corporate customers. ” This gives a hint of why femtocells may be unattractive to businesses: many of them would rather not yield this control.

Consumer voice service is controlled by service providers. They have three options in this space: do nothing, deploy femtocells or deploy Wi-Fi. Do nothing is the obvious best choice, since neither of the other options carries a revenue upside. But poor coverage in a home discourages usage and risks cancellations of subscriptions. So in areas of poor coverage something like femtocells or UMA (voice over Wi-Fi) is attractive to service providers. For both technologies the service provider subsidizes the wireless router, but femtocells will remain more expensive than Wi-Fi routers because of their lower sales volumes, so Wi-Fi is more attractive on this count. But UMA requires phones with Wi-Fi, while femtocells will work with any phone in the service provider’s line-up, including legacy ones. So the customers’ experience of femtocells is better – they can choose or keep the phone they want and still get improved coverage at home. This benefit of femtocells clearly outweighs the marginal price advantage of Wi-Fi routers. Femtocells may help subscriber retention in another way: a Wi-Fi router is not tied to any particular cellular service provider, while a femtocell only works with the carrier that supplied it.

The situation in businesses is different. They generally prefer to control their own voice systems, which is why they have PBXs. But a substantial number of business calls are now made on cell phones, even on company premises. These calls don’t go through the PBX, so they are not least-cost-routed and they are not logged or managed by the IT department. Femtocells don’t fix these problems, but Voice over Wi-Fi does. Not service provider Voice over Wi-Fi, like UMA, but SIP-based Voice over Wi-Fi from companies like DiVitas and Agito. What about phone choice though? Won’t corporate customers be stuck with a limited choice of handsets? The answer is yes, only a limited number of phones have Wi-Fi: less than 10% of those sold in 2008. But in the category of enterprise smart phones, like the Nokia Eseries and Blackberries, the attach rate of Wi-Fi will soon be close to 100%.

So femtocells are a good way for service providers to remedy churn caused by poor residential coverage for consumers, but Wi-Fi may be the better option for businesses that want to regain control over their voice traffic.

Wi-Fi certification for voice devices

In news that is huge for VoWi-Fi, the Wi-Fi Alliance announced on June 30th a new certification program, “Voice-Personal.” Eight devices have already been certified under this program, including enterprise access points from Cisco and Meru, a residential access point from Broadcom, and client adapters from Intel and Redpine Signals.

Why is this huge news? Well, as the press release points out, by 2011 annual shipments of cell phones with Wi-Fi will be running at roughly 300 million units. The Wi-Fi in these phones will be used for Internet browsing, for syncing photos and music with PCs, and for cheap or free voice calls.

The certification requirements for Voice-Personal are not aggressive: only four simultaneous voice calls in the presence of data traffic, with a latency of less than 50 milliseconds and a maximum jitter of less than 50 milliseconds. These numbers will produce an acceptable call under most conditions, but a network round-trip delay of 300 ms is generally considered to approach the limit of acceptability, and with a Wi-Fi hop at each end running at the limit of these specifications there would be no room in the latency budget for any additional delays in the voice path. The packet loss requirement, 1% with no burst losses, is a very good number considering that modern voice codecs from companies like GIPS can yield excellent sound quality in the presence of much higher packet loss. This number is hard to achieve in the real world, as phones encounter microwave ovens, move through spots of poor coverage and transition between access points.

Since this certification is termed “Voice-Personal,” four active calls per access point is acceptable; a residence is unlikely to need more than that. Three of the four access points submitted for this certification are enterprise access points. They should be able to handle many more calls, and probably can. The Wi-Fi Alliance is planning a “Voice-Enterprise” certification for 2009.

There are several things that are good about this certification. First, the WFA has seen fit to highlight voice as a primary use for Wi-Fi, and has set a performance baseline. Second, this certification requires some other certifications as well, like WMM power save and WMM QoS. So far in 2008, of 99 residential access points certified only 6 support WMM power save, and of 52 enterprise access points only 13 support WMM power save. One of the biggest criticisms of Wi-Fi in handsets is that it draws too much power. WMM power save yields radical improvements in battery life – better than doubling talk time and increasing standby time by over 30%, according to numbers in the WFA promotional materials.

Making lemons into lemonade

Phybridge is a Canadian startup (founded May 2007) aiming to solve some of the problems of VoIP implementation. Its premise is that in many cases, an organization seeking to move from a traditional TDM phone network to a VoIP network does not have an Ethernet LAN capable of supporting VoIP. This inadequacy may result from insufficient capacity, QoS or reliability.

The conventional solution in these cases is to upgrade the Ethernet network while junking the old phone wiring.

Phybridge proposes to leave the Ethernet network alone, and to reuse the old phone wiring to implement a parallel data network, using Ethernet over a flavor of DSL. This is similar to HomePNA, but aimed at business use rather than consumer, and done point-to-point rather than into a shared medium.

The solution consists of two parts: a central box called “Uniphyer” has 24 ports connected to the legacy phone wiring. At the other end of each cable run is a “phy adapter” the size of a pack of cigarettes that you plug into the legacy phone jack, and into which you plug your Ethernet VoIP phone.

The Uniphyer provides power over the same copper pair as the data, so you can plug power-over-Ethernet phones into the client adapters.

The data rate is 3 megabits per second upstream, 30 down. This is slow for a data network, but certainly adequate for VoIP, so an organization that is replacing a conventional PBX phone system with a VoIP one may find Phybridge a cost effective solution if their existing data network isn’t up to VoIP, and the required improvements are extensive.

The Uniphyer is scheduled to launch at the end of September.

Agito and Cisco Motion

Agito Networks was in the news recently as a part of Cisco’s Motion announcement. I have mentioned Agito a couple of times before in this blog. Like DiVitas it offers PBX-agnostic enterprise-based fixed-mobile convergence.

One of Agito’s unique technical claims is that it employs location based technology as one of the factors to determine the handover between Wi-Fi and Cellular (and vice versa).

The RoamAnywhere Mobility Router adds the element of location awareness to solve the challenging problem of routing between multiple networks.

From the Agito website

The Mobile Intelligent Roaming component of Cisco’s new Mobility Services Engine (MSE) also uses location as one of the factors (the other are signal strength and signal quality) to determine when to hand off between networks. This incorporation of location awareness into the MSE’s handover recommendation appears to weaken Agito’s claim to uniqueness in this respect, so why is Agito so enthusiastic about the MSE?

The MSE boils down an assortment of metrics related to handover decision-making to a simple binary message – link-up or link-down – which it sends to a third party eFMC controller like the Agito RoamAnywhere Mobility Router. The message is a recommendation, not a command, but since the MSE sends just this binary event, rather than any of the metrics that go into it, Cisco seems to be claiming responsibility for the decision about when to hand over.

Rather than simply obeying the link-up or link-down event by changing networks, the Agito mobility router takes these events as triggers to run its own handover-decision algorithm, using metrics gathered by the handset. This makes sense for several reasons. First, the Agito location determination mechanism is more precise for this particular application, since it knows when it is going through a doorway, whereas the Cisco location mechanism has a more general idea about the perimeter of the building. Second, the entire Agito handover-decision algorithm has to be maintained regardless of how good the MSE is at making the decision, because in many places there is no MSE (at home, in public areas, in buildings with non-Cisco networks and in buildings with Cisco networks lacking an MSE).

So Agito views the information from the MSE as a mere additional factor for its handover decision-making, rather than a substitute. On the other hand, Cisco’s marketing program around the MSE is a huge benefit to Agito.

Even though this part of the MSE will not be released until later this year, Agito’s Mobility Router works fine without it; the Cisco Motion announcement has led to a burst of interest in Agito from Cisco’s channel partners. According to Cisco, it has 65% share of enterprise Wi-Fi infrastructure, so Pej Roshan, Agito’s V.P. of marketing, anticipates that the relationship will “slingshot us to the next level of sales and customers.”

Cisco’s Motion Announcement

Cisco’s Motion announcement on May 28th was huge for enterprise mobility. It defined some new terms which we will be hearing a lot: “Cisco Motion,” “Mobility Services Architecture” and “Mobility Services Engine.” Cisco Motion is the name of the “vision.” The Mobility Services Engine 3350 is a $20,000 appliance that embodies the Mobility Services Architecture, which is a part of Cisco’s Service Oriented Network Architecture.

Cisco has published a lot of useful information about these new products. A good place to start is the launch webinar, which includes an informative Powerpoint presentation. The Mobility Services Architecture is described in a white paper. There are two press releases: a conventional press release consisting of written words, and a “social media release” consisting of links to YouTube clips and podcasts.

What we’re doing here is abstracting the network control element of the architecture and the services and application integration piece. This reflects what we have been talking about for the last 2 plus years around the Services Oriented Network Architecture. It’s about how we can drive new capabilities into the network, that can be married up with a host of different applications and turned into a solution for our customers. It’s not just applications running over the network. Increasingly with this architecture, it is about applications running “with” the network.

Ben Gibson, Senior Director Mobility Solutions, Cisco Systems

Cisco describes the MSE as a “platform for partnering,” the idea being that it exposes network-level information through an open application programming interface (API) to applications delivered by independent software vendors (ISVs).

Adding wirelessness to the IP world generates network-layer information that can be useful to applications, notably information about the location of known devices, and the intrusion of unknown devices. The MSE orders that information and presents it through the API.

Cisco Motion also addresses some downsides of mobility. Adding mobility to the IT world brings a lot of new headaches:

  • There are multiple network types (currently cellular and Wi-Fi, later WiMAX)
  • There is a profusion of new device types (currently smart phones) which must be managed and tracked
  • There is a wave of innovation in consumer applications. Employees are demanding these applications in the enterprise environment.
  • Mobility also complicates compliance with data confidentiality regulations like PCI and HIPAA.

So far Cisco has identified four categories of application that can run on the MSE: Context-Aware applications, Wireless Intrusion Prevention Systems, Client Management and Intelligent Roaming.

Context Aware Applications
“Context Aware applications” seems to be Cisco’s term for applications that do asset tracking. Cisco is partnering with ISVs in both horizontal and vertical markets. These ISVs are OAT, Intellidot, Aeroscout, Pango/Innerwireless and Airetrak. The Context-Aware software is scheduled to ship in June 2008.

Adaptive Wireless Intrusion Prevention Systems

Overlay wireless intrusion prevention systems add devices to monitor wireless traffic looking for rogue access points and clients. The innovation here appears to be that the MSE exposes information from the access points and wireless controllers that eliminates the need for these overlay devices. IPS software running on the MSE can substitute for the overlay IPS, while yielding equivalent depth of reporting and features. A further benefit of running the IPS over the MSE API is that the same software will be able to handle future wireless networks in addition to Wi-Fi. The Adaptive WIPS software is scheduled to ship in the second half of 2008.

Mobile Intelligent Roaming

This is enterprise Fixed-Mobile Convergence. The MSE isn’t a mobility controller; it issues an event up through the API when it determines that the Wi-Fi network needs to hand the call off to the cellular network. This event is handled by mobility controller software from an ISV. Cisco’s launch partners for this are Nokia for phones, and Agito on the mobility controller side. The Mobile Intelligent Roaming software is scheduled to ship in the second half of 2008.

Secure Client Manager

This works with Cisco’s 802.1X and CCX products. Cisco estimates that 80% of IT’s wireless and mobility effort goes to client troubleshooting and security provisioning. The Secure Client Manager will help mitigate this problem for the imminent wave of mobile devices. The Secure Client Manager is scheduled to ship in the first half of 2009.

Unified Wireless Network Software

Cisco Motion requires a new software load for the access points and WLAN controllers: the Cisco Unified Wireless Network Software Release 5.1, which shipped in May 2008.

What is Enterprise FMC?

“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean — neither more nor less.”

The term “Fixed Mobile Convergence” is an umbrella for so many different things that it has become almost meaningless when used without elaboration. Here’s how it started out, in the 2004 press release announcing the formation of the FMCA:

Fixed-Mobile Convergence is a transition point in the telecommunications industry that will finally remove the distinctions between fixed and mobile networks, providing a superior experience to customers by creating seamless services using a combination of fixed broadband and local access wireless technologies to meet their needs in homes, offices, other buildings and on the go.

In this definition “Fixed broadband” means a connection to the Internet, like DSL, cable or T1. “Local access wireless” means Wi-Fi or something like it. BT’s initial FMC service actually used Bluetooth rather than Wi-Fi for the local access wireless. The advent of picocells and femtocells means that the local access wireless can be cellular radio technology.

The term “seamless services” in the quotation above is ambiguous. When talking about FMC, the word “seamless” usually refers to “seamless handover,” which means that a call in progress can move from the mobile (cellular) network to the fixed network on the same phone without interruption, as described in one of the FMCA specification documents:

Seamless is defined as there being no perceptible break in voice or data transmission due to handover (from the calling party or the called party”s perspective).

The term “Seamless services” sometimes means service equivalence across any termination point, fixed or mobile, so for example, dialing plans are identical and no change in dialed digits is required on a desk phone versus a mobile. A less ambiguous term for this might be “Network Agnostic Services.” To do it properly is very difficult, for example I have not been able to track down an Enterprise FMC system that offers SMS on the desktop phone.

The FMCA is a carrier organization, mainly oriented to consumer services. Enterprise phone systems are different. When Avaya announced its “Fixed Mobile Convergence” initiative in 2005, it was using a different definition. What Avaya and other PBX manufacturers were calling FMC was the ability for a PBX to treat a cell phone as an extension, and the ability for a cell phone to behave like a PBX extension phone:

Extension to Cellular technology: software seamlessly bridges office phone services to mobile devices, permitting the use of just one phone number and one voice mailbox.
Client software extends the capabilities of the PBX to a mobile smartphone – creating a virtual desk extension. This software runs on Nokia Series 60 phones and works in conjunction with Extension to Cellular.

In other words, this new definition of FMC didn’t include local access wireless and it didn’t include fixed broadband technology. The only defining characteristic it shared with the previous definition was seamless services, albeit without seamless handover.

“The question is,” said Alice, “whether you can make words mean so many different things.”
“The question is,” said Humpty Dumpty, “which is to be master – that’s all.”

We can regain mastery here by breaking out the features of the various definitions of Enterprise FMC, giving them names, and using those terms to describe the various solutions on offer. Here’s a first cut:

Session Redirection
This simply means moving a call in progress from the cell phone to desk phone or vice-versa, in much the same way as you might transfer a call from one extension to another. For example, you are in your car on the way to work, listening in on a conference call on your cell phone. You walk in to the office, sit down, and redirect the call (session) to your desk phone. Depending on the implementation, you might control the process from your cell phone, your desk phone or your PC, using touch-tones or something more user-friendly.

PBX Mobility
This is what the Avaya press release called “Extension to cellular,” and some other vendors call “PBX Extension.” You program the cell phone number into the PBX (or third party PBX Mobility device – see the paragraph below headed “PBX Agnostic”), and then when somebody calls your office number, the PBX dials your cell phone over the PSTN and bridges the call. The PBX treats the cell phone as though it is an analog extension, so you can invoke PBX features like hold and transfer by touch-tone commands. This means that you can use any cell phone and any carrier (see the paragraphs below headed “Handset Agnostic” and “Carrier Agnostic”.)

Treating the mobile phone as an analog extension to the PBX opens up several more possibilities. Various flavors of this service might include features like Single Number, Simultaneous Ringing and Single Voicemail.

“Single Number” means that the mobile phone and the desk phone share an extension number. So you only need to give out one phone number to receive calls on either your mobile or desk phone. But bear in mind that your cell phone probably still has its own number – it’s just that you don’t give it out to anybody. In order to make business calls from your cell phone, you dial an access number at your office, get a new dial tone, and then dial the destination number. This allows you to take advantage of corporate least-cost-routing, and it shows your office number on the Caller ID display of the person you are calling.

Single Voicemail is the option to use the corporate voice mail rather than the cell phone’s voice mail. This only works on calls made to your office number.

“Simultaneous Ringing” means that when somebody calls your office number, your desk phone and your mobile phone ring simultaneously.

When your cell phone receives a call made to your office number, the Caller ID display would normally show your office as the caller, since the call is routed though the PBX. When the client software on the cell phone can pre-empt the built-in phone software (depends on the handset and the client software vendor) this Caller ID is suppressed and the mobility controller passes the correct calling number and name to the client software on the handset using the cellular data channel. Alternatively, depending on your PBX and carrier, the system may be able to insert the Caller ID of the person calling you into the regular Caller ID notification (Caller ID spoofing). This will show the ‘correct’ Caller ID even on the built-in handset interface.

Client Software
PBX Mobility on a regular cell phone is not particularly user friendly, what with the touch-tone interface and the access number prefixing. With a smart phone things get a lot better. The definition of a Smart Phone is that it can run third-party software. If you happen to have a smart phone, and it is a model supported by your Enterprise FMC system, you will be able to run a “Client application” that puts a friendly user interface on the PBX Mobility features, allowing easy use of PBX features like 4 digit dialing to other extensions.

If the phone supports it, well written client applications can completely hide the native phone user interface. Otherwise users will have two different screens from which to dial calls – the built-in one and the client application.

RIM has built PBX signaling features into its handsets running firmware version 4.2.1 or higher. This means that Blackberries can access PBX features through menus rather than touch-tones, even without add-on client software.

Dual-mode Phone Support
A dual-mode phone is a cell phone that also has Wi-Fi. The Wi-Fi can be for data only (like the iPhone), for voice only (like the Nokia 6086), or for both.

There are two main categories of wireless extensions to PBXs: those that work over Wi-Fi (VoWLAN, or VoWi-Fi), and those that use other radio technologies like DECT. Client software can make a dual-mode smart phone act as a Wi-Fi extension to the PBX. This gives the handset a split personality: a regular cell phone and a VoIP PBX extension, each having its own phone number. These two personalities can be well integrated, completely separate or something in between. Session Redirection as described above moves the call between devices; with a dual-mode phone, you can do Session Redirection between the two networks, keeping the call on the same handset.

Well integrated dual-mode user interfaces are sometimes described as “Network Agnostic” (see below).

Session Continuity
Dual mode handset clients can completely hide their split personality, taking the onus of Session Redirection off the user, and dealing with it automatically. When the system senses that you have walked into Wi-Fi coverage it moves the call over onto the VoWi-Fi side. When you move out of Wi-Fi coverage it moves the call back to the cellular side. This is also sometimes called “seamless handover” or “automatic handover.” To do it imperceptibly to the user is technically challenging. This automatic, seamless flavor of Session Redirection is often termed VCC, or Voice Call Continuity. The term VCC has the disadvantage that it specifically mentions voice, while FMC systems are evolving towards multimedia sessions where voice is only one of the elements. So a better term might be Session Continuity.

Session Continuity requires client software support in the handset, either with built-in VCC client software, or (more commonly in Enterprise FMC) as a part of the client software from the Enterprise FMC system vendor.

Mobility Controller
VCC is a term lifted from the IMS (IP Multimedia Subsystem) specifications published by the international bodies concerned with standardizing cellular technologies. In IMS terminology, VCC is done by software called the “Call Continuity Control Function,” or CCCF.

Session Redirection and Session Continuity require a device in the network that routes and reroutes the call over either the fixed or mobile network as needed (that is to say, something that embodies the CCCF.) There are many terms for this device, and each of these terms can also mean something else. Also the various devices that incorporate Session Redirection or Session Continuity usually also do other things. These devices have names like “Mobility Server,” “Mobility Controller,” “Mobility Router,” “Mobility Appliance” or “Mobility Gateway.”

Carrier FMC and Enterprise FMC
The path of a call transits both the service provider network and the enterprise network, and the Mobility Controller can be located just about anywhere on that path. If it is in the service provider network we call the system Carrier-based FMC, if in the enterprise network, Enterprise FMC. This is the defining characteristic of Enterprise FMC.

Most Carrier-based FMC is aimed at the consumer market, but there are some implementations that support enterprise features like PBX Mobility. Carrier-based FMC can support PBX Mobility either by installing a PBX Mobility control device near the PBX in the enterprise network (the approach taken by Tango Networks), or perhaps by offering the PBX functionality as a network service (Centrex), the approach taken by Sotto Wireless.

Carrier FMC normally uses one of two technologies to implement Session Continuity, VCC or UMA (Unlicensed Mobile Access, also known as GAN, for Generic Access Network). UMA is an older technology, which transports GSM packets through the IP network; the handset uses the same GSM signaling stack for Wi-Fi calls as for cellular. With the predicted conversion of the carrier networks to all-IP, UMA has been superseded by VCC, which uses SIP signaling.

Handset Agnostic
We mentioned above that basic PBX Mobility can work with any cellular handset. At the other extreme, Carrier FMC usually only works with particular handsets. For example the T-Mobile@Home service works with only three handsets, one each from Nokia, Motorola and RIM. Client software for Enterprise FMC almost always works on phones that run the Windows Mobile or S60 operating systems, particularly the HTC phones and the Nokia Eseries respectively. Other smartphone operating systems that may be supported include Linux and RIM, and in the future OSX and Android. Handset agnosticism is a major selling point. A handset agnostic system is more attractive to Enterprise FMC customers than one that limits the choice of handsets.

Carrier Agnostic
A system with the Mobility Controller in the enterprise network can work with any carrier, provided the carrier will allow the phones to connect to their network. The benefit of this is that the customer gets a wide selection of phones, and the FMC system will work on employees’ personal phones, even when those phones are on an assortment of carriers.

A system with the Mobility Controller in the carrier network is not carrier agnostic from the point of view of the customer. They have to buy service from that carrier.

PBX Agnostic
Each of the PBX vendors offers a mobility capability. Some developed it internally. Some, like Cisco or Avaya, bought a third party developer, and some license their offering from a company like Telepo , Comdasys or Counterpath (formerly FirstHand). There is another set of vendors that offers Enterprise FMC that works with any PBX, for example DiVitas, Agito, Tango and RIM. This is beneficial to both large and small customers. Large customers may have PBXes from multiple vendors, yet still wish to roll out a unified FMC solution. Small customers appreciate having a choice of supplier, rather than being tied to their PBX vendor.

Network Agnostic Interface
Some vendors use this term to mean that all features are available through a uniform user interface in both cellular and Wi-Fi networks. This means that the user should not be able to perceive which network is carrying their session on a dual-mode phone.

Agonizing over minute definitions is tedious, but when evaluating competing solutions it is essential to be able to recognize when two vendors use the same term in different ways, when they use different terms for the same feature, or when they describe a feature without giving it a name.