Verschenen in Automatisering Gids nr. 40, 2008

De informatie of iemand bereikbaar is en hoe, verandert de komende tijd ingrijpend. Volgens experts wijzigt daardoor ook het gebruik van communicatiemiddelen. ‘Presence’-informatie is in basale vorm bekend van sociale netwerken, instant messaging en een aantal openbare VoIP-aanbieders. Dit zijn echter bedrijfseigen systemen en de informatie over bereikbaarheid is nog beperkt.

Twee standaarden, SIMPLE en XMPP, brengen daar verandering in. De consequenties komen op 10 oktober aan de orde op het congres ‘Future of Presence’, georganiseerd door onder meer de ISOC in de Koninklijke Bibliotheek in Den Haag.

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June 2008, NXTComm/Las Vegas

Peer-to-Peer Sesssion Initiation Protocol (P2PSIP) provides a conceptually simple, standards-based mechanism to distribute functionality, leveraging the power of clusters of devices, rather than a single centralized box.  At the heart of P2PSIP is a notion of providing a distributed "fabric" of devices that are able to provide these same services and functionality with little or no centralized infrastructure. P2P systems do not eliminate work that would be done by a centralized device in traditional client-server architecture, but rather distribute that work differently, pushing the functionality to the edge. As a result, there some advantages to a P2P architecture (for example improved scalability and reliability) and some areas where a conventional CS system may be better (for example number of hops involved to route a message).

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It was for me an interesting an utterly refreshing experience to sit face to face with the inventors of SIP and to learn of its extensions to many applications beyond Voice over IP such as presence, mobility and emergency services. On the panel were present also mobile and fixed line service providers as well as technology vendors.

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Easy service creation is one of the highlights of the SIP protocol. It promises a low cost, quick development cycle for applications around SIP. With so much theory on paper and more than two years of live deployments, what can SIP offer today in terms of classic telephony features and value added services?

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Traversing NAT (Network Address Translation) is one of the issues that hinder SIP communications. Some background about the problem: With an ideal Internet, all devices would be able to communicate end to end without any intermediaries except routers. This assumes each device has a routable IP address, a public reachable Internet identity. In reality, today many of the devices connected on the Internet are using a NAT function present in the border router. While this stops the Internet to initiate connections to the device (bad for IP telephony or other forms of peer-to-peer communications), it also protects the users against malicious attacks. Using NAT, one may also connect multiple devices to the Internet by only using one public IP address. So NAT has both advantages and disadvantages.

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Published by ETSI 

ENUM, a convergence tool for translating telephone numbers into Internet addresses used by IP telephony and next generation mobile networks like UMTS, is a key ingredient for the transition to the Next Generation Networks.

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