In this webinar, Peter Saint-Andre, Chair of the XMPP Council, Oren Avissar, Director of Engineering, ooVoo and Joe Hildebrand, CTO, Jabber, Inc. join me in discussing:

• The history of Jabber/XMPP and Jabber, Inc.
• The XMPP Community and its governance process
• ooVoo’s presence-enabled multi-user video and voice communications service and other applications of Jabber XCP

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Here is an example use case of the technology in this announcement: imagine that your best friend at work has one XMPP device and one SIP device, both of which are online, publishing presence. When you subscribe to her with either protocol, you will see an aggregated view of her presence, including the presence all of her devices.

This is a unique solution providing aggregated presence for SIP/SIMPLE, XMPP and other protocols. Don’t confuse presence aggregation with federation. Aggregation collects presence information within a system, where it can be processed, filtered and published. Federation allows two or more systems to publish and subscribe to each others’ presence. Presence aggregation, particularly in multi-protocol, high-scale systems, is a much harder challenge than federation. Working together, Avaya and Jabber have met this challenge.

This announcement is another example of how presence is essential for unified communications, collaboration applications and real-time services. It also is proof positive of the fact that presence is useful for much more than instant messaging. In contrast to conceptual discussions on this blog discussing the types of applications driving demand for presence software and the critical requirements of presence platforms, this announcement is concrete - a real solution for real-world, real-time applications.

Participating in this solution has been of great value to Jabber in enhancing our multi-protocol technology and organizational knowledge. SIP is well established, particularly for applications incorporating digital telephony. Use of XMPP is growing rapidly the consumer, enterprise and government markets, with new presence-enabled applications and services based on the protocol being announced/uncovered on a weekly basis (read the hot scoop on new XMPP activities and applications here).

In case it isn’t clear, the value of presence is driven by Metcalfe’s Law. As more presence-enabled nodes (people, apps, devices, etc.) are added to a network, the value of the presence information grows exponentially. As there are several presence protocols, the only credible presence servers are those that are multi-protocol. It was challenging for Jabber, Inc. to become a multi-protocol presence server, but just being a presence server that only supports one protocol doesn’t cut it anymore.

But there are some road blocks ahead. The first one is that most clients out there don’t deal properly with negative priorities. If a buddy of mine only has negative priorities, my IM client must show him as offline. Most clients right now, don’t do that.
[Negative priority]

I agree with Pedro that it’s not clear how clients should render negative-priorty presence. This post outlines one possible approach. Just so that we have some concrete protocol to discuss, consider a PBX that injects the following presence on your behalf:

<presence from=“joe@example.com/phone“>
  <priority>-1</priority>
  <status>On the phone</status>
  <show>away</show>
  <c xmlns=“http://jabber.org/protocol/caps“
     hash=“sha-1“
     node=“http://jabber.com/bots/pbx“
     ver=“PwgGa/jZx9sUeueZsjT/xBlJfqo=“/>
  <reach xmlns=“http://jabber.org/protocol/reach“>
    <addr uri=“tel:+1-303-555-1212“/>
    <addr uri=“sip:joe@example.com“/>
  </reach>
</presence>

Let’s step through this bit by bit.

• Priority: -1, obviously, since that’s what we’re here to talk about. We would rather have messages be sent offline than come to this resource. It’s never the most available resource for this user.
• Status: We’re off-hook.
• Show: use the away icon. Which actual image should we show, though?
• Entity capabilities: a pointer to information about the software that sent the presence. The node URI is a semantically-relevant descriptor of the client, and the ver attribute is a hash of the features and other information about that client.
• Reach: how else can this device be reached? In this case, a POTS phone number and a SIP URI. This namespace is from the deferred XEP-0152, and is just here to give a little more flavor to the presence.

Assume that this is the only presence for this user at the moment. Now, imagine the client of a subscriber to this person, with a user interface that looks something like this:

This person is seeing me as offline for IM, and my phone is off-hook. There is an image for each of my negative-priority resources; presumably when I mouse over the image, something interesting will pop up, like “On the phone”. If I click on the image, I might be given options like “Call”, which could use the tel: URI in the reach section. One potential issue is what to do if there are too many negative-priority resources - that’s something for the UI designers to deal with, though.

But, how do we actually decide what image to show? There are several ways:

1. Hard-code a mapping between the (caps node, show) pair to a resource in the subscriber’s client. This would work, but is obviously limited for the future.
2. Hard-code a mapping between the (caps identity, show) pair of the device and a resource in the subscriber’s client. This is similarly limited.
3. Do an IQ to the publisher to ask what it’s current image is. With this one it’s hard to know when to cache, so scalability suffers.
4. Use one of the avatar XEPs (like 0153), and include an image reference in the presence. This doesn’t work because the avatar is for the identity of the person sending the presence, not for the software or device.
5. Create a new namespace that has a URL for the current presence icon. This would work just fine, and normal web caching would get us everything we need. It would increase the size of every presence stanza, though.
6. Add a couple of new fields to the XEP-0232 software information that comes along with the caps. There would be a field for each presence state that you care about, where the value of that field is a URL to an image.

This last approach is obviously the one I favor. The caps result would look like this:

<iq from=“joe@example.com/phone“
    to=“subscriber@example.com/work“
    id=“disco1“
    type=“result“>
  <query xmlns=“http://jabber.org/protocol/disco#info“
         node=“http://jabber.com/bots/pbx#PwgGa/jZx9sUeueZsjT/xBlJfqo=“>
    <identity category=“client“ type=“bot“ name=“PBX“/>
    <x xmlns=“jabber:x:data“ type=“result“>
      <field var=“FORM_TYPE“ type=“hidden“>
        <value>urn:xmpp:dataforms:softwareinfo</value>
      </field>
      <field var=“icon“>
        <value>http://jabber.com/pbx.png</value>
      </field>
      <field var=“icon_available“>
        <value>http://jabber.org/pbx_available.png</value>
      </field>
      <field var=“icon_away“>
        <value>http://jabber.org/pbx_away.png</value>
      </field>
    </x>
  </query>
</iq>

In this case, there is a general-purpose icon field, and then one icon_[show] field for each show that we will be sending. Whenever the subscriber gets a new negative-priority presence update, it looks in its caps cache, pulls out the field for the appropriate show, and pulls the image URL through an HTTP client that does caching (or does it’s own manual image caching). The image is scaled into the desired size, and displayed in the user interface. If these fields are added to XEP-0232, we should probably specify a desired image size, like 128×128 pixels.

We have started to see our customers and partners send negative presence, and are feeling the pain of client UI that doesn’t know how to deal with it. The first step for us is to figure out the correct protocol to deal with the UI issues. We’ll push this into MomentIM as soon after that as release cycles allow.

XMPP is enhanced and extended through a standards process around XMPP Extension Protocols (XEPs). Jabber, Inc., has a long history of participation in the standards process (back to the days when XEPs were called JEPs) and through the years, support for many XEPs have been added to Jabber XCP, Jabber’s flagship XMPP server.

Our developers are at it again, adding support to Jabber XCP for XEP-0163: Personal Eventing via Pubsub, which should be of interest to anyone following the evolution and use of presence technology. XEP-0163 lets users send updates about anything to users on their rosters. Personal eventing lets people easily publish things about themselves - it doesn’t get any more user-centric than this! The updates are sent using the XMPP Publish-Subscribe functionality used in Jabber XCP’s InfoBroker and described in XEP-0060. One way to look at it is that XEP-0163 takes XEP-0060 functionality to a more personal level.

I was skeptical when we first started talking about adding this enhancement. The use cases in the XEP include sending updates on your current mood and what music you are listening to. I immediately understood the value of personal geolocation, a classical extended presence element, but mood? Why should Jabber’s customers at leading service providers, enterprises and government agencies care about such personal and subjective elements?

But then I had an epiphany: Presence is intrinsically personal and becomes more valuable as more details are added. Plus, personal subjective thoughts and feelings have major impacts on our world. Mood (sometimes veiled in more scientific words such as “sentiment” or “perception”) can determine the outcome of elections, move capital markets and have a major impact on the success of corporate, military and organizational initiatives. Things get really interesting when the extended presence details of many individuals are aggregated and analyzed. You probably don’t care what mood I’m in, but wouldn’t it be interesting to see the aggregated mood of everyone in your company or organization? How about the aggregated, real-time sentiment of voters, soldiers, traders or everyone in an online community, particularly if the information is up-to-date, accurate and made anonymous at the individual level?

The success of Twitter (which has XMPP in its architecture, BTW) and other similar services proves that personal eventing (in addition to presence, in general) is valued in social network settings. Service providers should be interested in the increased stickiness that personal eventing brings to their communities. Once users get used to seeing their friends’ moods, blog posts, activities, etc. they are more likely to stay in the communities which publish these details. The extension of social network technology to enterprise applications is in full swing, so by adding support for Personal Eventing via Pubsub to Jabber XCP, our extensible and highly scalable real-time presence and messaging platform will take the Power of Presence to a more personal and valuable level. The customers we’ve talked to about PEP have some great use cases and they will use this new functionality in their deployments. How about you?

It is an honor to provide software and services in support of the mission of one of the world’s most renowned and agile military organizations. While best known for its prowess in battle, the USMC is also a leader in the use of technology. I have no doubt that the extensibility, scalability and interoperability of the Jabber XCP platform will facilitate its use in a broad range of innovative applications within the Corps.

We need to think of presence more along the lines of a lifestream or activity stream where a variety of information is published into the stream and people can subscribe to the entire stream or to different types of information placed into the stream.

This new presence construct generates an essentially continuous stream of information of what someone is doing, where they are, etc. I believe that in this new model, the presence publisher, in addition to the subscriber, requires granular control over who can see what elements of their presence stream. I also see a future where presence gains more use cases where it is applied to things, in addition to people.

As an example of the use of presence platform software, read how the Me.dium social browsing application integrates Jabber XCP as its presence and messaging platform.

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To be broadly useful, presence platforms must be scalable, highly available, extensible and able to work with other middleware and network services. It is worth noting that some of these requirements are the same or very similar to the requirements of more established types of platform middleware, particularly services at the edge of the network, such as Web servers and application servers. This is because presence platforms in commercial deployments have similar, and in some cases, greater demands placed on them by the enterprise applications, consumer-facing services, etc. that they support.

The ability to scale is critical because presence must, by definition, be a real-time service. In commercial applications, a presence server must scale to be able to route presence information between millions of network nodes. Millions of points of presence are not uncommon, even in traditional enterprise settings. When counting points of presence, consider that a single person, device or sensor can have multiple presence elements. For example, a person with a desktop computer, and both desktop and mobile telephones has three points of presence, not counting additional presence states of presence-enabled applications running on their computer. With millions of nodes with changing presence states, a presence platform must be able to handle extreme message rates. For example, in some benchmark testing designed to model consumer service use patterns, rates of over 15,000 messages per second were observed. Without a highly scalable presence platform, presence information degrades into pseudo real-time information - what presence was, not what it is. Latency in the delivery of presence information greatly reduces its value and may cause errors and oddities in presence-enabled applications.

As presence is an always-on service, presence platforms must be highly available. The presence platforms which meet availability requirements typically have built-in architectural redundancy and auto-healing features designed to gracefully recover from outages on the network or at the network node level.

There is no such thing as a one-size-fits-all presence model. To allow the presence platform to be tailored to specific applications and services, it must provide developers ways to access and extend its capabilities. As there are several presence protocols in general use ( e.g., SIMPLE and XMPP) support for multiple standards makes it easier for application developers to make use of a presence platform when the presence nodes speak different protocols. To maximize interoperability and prevent vendor lock-in, presence platforms should be based on truly open standards and not rely on proprietary extensions. Another important development requirement is libraries to facilitate the creation of clients and software to connect network nodes and applications with the presence platform. A diverse set of libraries, such as is listed here, represents a major advantage for a presence platform, as it allows developers to work in the language that is most appropriate for their specific objectives.

Presence platforms are not stand-alone entities. In most use cases, presence platforms must interoperate with other network software, such as directory servers and data base services. As presence is often a new service added to an existing deployment architecture, the presence platform must be able to integrate with existing network middleware. To minimize data/hosting center floorspace and management costs, presence platforms should run on the most popular server operating systems, so a customer is not required to provision new hardware and train staff on the management of a new OS.

If you have deployed a presence platform or are planning to do so, do you have other requirements?