Why are we still talking about something that has been around since Call Manager 7.x? Why is a dial plan built around URI not more common place? Why is it still something most people only think about in reference to video?

At the outset, the purpose of the URI is exactly what the name states, a Universal Resource Identifier. For those unfamiliar with URI or SIP URI, it is basically an alphanumeric ID that is reachable across the web. It seems like a perfect fit with Cisco’s vision of an all-encompassing communication platform, and in large part it is. In concept, the goal is to have a single address at which to contact someone regardless of the medium you choose. In other words, mbalcer@stack8.com becomes my e-mail address, my instant messaging ID, my video call number, and yes even my phone number. Isn’t this what IP telephony and UC were built for?

We know that not every environment is ready to take that step today and that there are caveats to getting this to work in the way described above. In some cases, there may be domain changes and complex call routing required. What we know is that at its most basic level, SIP URI integration in your dial plan or at least a URI directory adds significant flexibility.

The first and clearest advantage is the facilitation of a truly unified environment. Since URI is the native dialing method for video calling it makes sense that we move towards a globalized method that at the very least incorporates URI dialing. Until then, and for the near future, perhaps using a “Blended Identity” method is the way to go, whereby each platform (telephony, video, and softphone) uses their native dialing method and each resource essentially has a blended identity of URI and Directory Number in CUCM . This essentially means that not only does the technology choose their preferred identity, but that the users can use their choice of dialing method to reach a resource.

Once URI is integrated into the dial plan, it also enables integration across multiple video platforms, such as MS Lync and H323 standardized video platforms with Cisco. URI is the standardized resource ID across most of these platforms so even within an organization where there might be multiple vendors that make up “Unified Communications” URI is a must. It is even more essential for B2B video, IM&P and federation between organizations. B2B video and federation are becoming severely more complicated, if not impossible without the use of a standard web address.

There are other secondary advantages of a URI dial plan integration that do not even relate to video. The ability to scale is certainly one of those advantages. As organizations restructure, globalize, merge, and grow it becomes more difficult to adapt an existing Directory Number plan to this reality. I have seen organizations grow from 4-digit dial plans to 10-digit dial plans overnight. This transition is certainly cumbersome for users. Whereas, the ability to use a directory that is URI based or click to dial using a colleague’s e-mail address is far more intuitive. A user is no longer required to understand why a new block of DNs is completely out of sync with other DNs or why they now have to dial an additional 2 to 6 digits to reach a colleague. Therefore, DN ranges and exceptions become almost irrelevant. There are caveats that need to be addressed such as ILS (Intercluster Lookup Service) for organizations that span across multiple clusters. CUCM even allows you to associate multiple URIs per DN which can allow for simplified internal URIs and more complete external URIs. Digit based directory number dial plans are finite and become more complex through growth, whereas URI-IDs are nearly infinite and the complexity doesn’t change: it remains simple.

URI also helps adapt to the evolving user base. Gone are the days where every user just wanted a desk phone and UC applications were secondary. In a recent project with a university, nearly half the users chose to have only Jabber, as instant messaging, video, and content sharing was their primary form of communication. URI allows for a user to have only Jabber and use their domain ID (hopefully their e-mail address) as their contact information. I’ve heard some C-level executives even state that allowing potential employees a choice of technology may be a key differentiator to attracting talent. I’m not here to sell that correlation but flexibility is always valuable.

SIP URI and URI dialing really are key pieces of the complex puzzle that intuitive and fully unified communications represent. Also, the advantages and benefits of this dialing method as standard are largely dependent on how and to what depth it is configured. Making your URI your universal communication “barcode” involves several components to be configured in concert and correctly. In fact, one of those key components is the Cisco Expressway server as described in a previous Stack8 blog by Eric Losier: “Living on the Edge: Make the Jump to Cisco Expressway” ; it is essential for B2B video communication and federation.

Interested in learning more about how you can make incorporate this into your environment, then stay tuned for next week’s blog post when Dishko Hristov explains the deployment considerations for SIP URI dialing or we can help with the architecture and design and even deployment of such changes: let’s talk!