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)
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.
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 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.
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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