Glossary

Mobile IP

Sun Microsystems Laboratories engineers James Kempf, Jonathan Wood, and Carl Williams (among others) are working to design and implement protocols and technologies that improve connection performance and reliability for cell phones and Internet devices as they physically move through different radio access networks and from cell to cell. (see "Mobile or Portable" sidebar)

SLP

The Service Location Protocol (SLP) is an IETF standard that is designed to reduce the manual configuration of devices that you connect to, wirelessly or otherwise. "SLP provides a scalable framework for automatic resource discovery on IP networks," says Sun Microsystems Laboratories engineer Erik Guttman. What SLP protocols and technologies automate is the discovery and setup of network resources, such as printers, web servers, mail servers, and calendars, as well as fax machines, video cameras, file systems, backup tape drives, and just about any imaginable IP device. The goal of SLP is to make all networked resources dynamically configurable through the use of IP-based service and directory agents. "As computers become more portable and networks larger and more pervasive, the need to automate the location and client configuration for network services also increases," says Guttman.

Guttman and Kempf worked on the draft SLP specifications for the IETF protocol. Kempf implemented the API and the Java[tm] programming language version of SLP for the Solaris[tm] 8 Operating Environment; Wood implemented the C portion of SLP for the same Solaris OE release. A number of prototyping projects are using SLP company wide.

SCTP

The Stream Control Transmission Protocol (SCTP) is a new, robust signal transmission technology for wireless communications. Designed by the IETF SIGTRAN working group, SCTP is the successor to the SS7 signaling protocol. SCTP's robustness stems from its capacity to maintain several data streams within a single connection. This makes SCTP ideally suited for connecting and monitoring wireless cell phone and Internet appliances. With SCTP, connections and signal paths can be actively monitored, and failures or losses of sessions can be instantly detected. Wood implemented a version of SCTP. "We have 20 customers that are looking to use it currently using SCTP prototypes," says Kempf. "There's a huge demand for it."

Diameter

Diameter is an IETF protocol that unifies authentication, authorization, and accounting (AAA) transactions. Diameter improves immensely on its less secure, less mobile predecessor, RADIUS. Combining accounting and security features, Diameter supports the business end of mobile IP service providers, keeping authentication simple and strong while minimizing overall response times and network overhead. Sun Microsystems Laboratories engineer Dave Frascone is implementating Diameter for Sun. Frascone, Kempf, and Pat Calhoun (a former Sun Labs member who recently founded his own startup company) designed the Diameter API.

OpenRAN

The IP radio access network (OpenRAN) is a new architecture for wireless radio access networks (RANs). The RAN is a network that bridges the radio link and the IP core network (the RAN performs the same role for CDMA and GSM radio networks as DSL or cable does between homes and the IP network in wired broadband). The IP-based RAN would replace ATM (Asynchronous Transfer Mode), reducing the costs of RAN equipment and improving compatibility with the Internet.

The Mobile Wireless Internet Forum (MWIF) published a study in January 2000 that demonstrated IP's superiority to ATM for the "last mile" RAN connection. This study prompted 3GPP, the Europe/Asia mobile communications standards body, to examine the feasibility of using IP as transport in the RAN. Five months later, in May 2001, MWIF completed the initial OpenRAN study for an architecture based on all-IETF protocols. 3GPP2, the North American mobile communications standards body, decided to adopt OpenRAN as the basis for its next generation RAN. Kempf chaired the working group at MWIF that was responsible for the IP RAN work.

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