Nortel Networks WEB OS 212777 - Manual (Page 158)

Web OS 10.0 Application Guide
158 n Chapter 6: Server Load Balancing
212777-A, February 2002
Wireless Application Protocol SLB
Wireless Application Protocol (WAP) is an open, global specification for a suite of protocols
designed to allow wireless devices to communicate and interact with other devices. It
empowers mobile users with wireless devices to easily access and interact with information
and services instantly by allowing non-voice data, such as text and images, to pass between
these devices and the Internet. Wireless devices include cellular phones, pagers, Personal
Digital Assistants (PDAs), and other hand-held devices.
WAP supports most wireless networks and is supported by all operating systems—with the
goal of inter-operability. A WAP Gateway translates Wireless Markup Language (WML)—
which is a WAP version of HTML—into HTML/HTTP so that requests for information can be
serviced by traditional Web servers.
To load balance WAP traffic among available parallel servers, the switch must provide persis-
tency so that the clients can always go to the same WAP gateway to perform WAP operation.
Web OS allows the Web switch to decide which real gateway the request should go. WAP SLB
is based on RADIUS static session entry or RADIUS snooping.
The following topics are discussed in this section:
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Using RADIUS Static Session Entries
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Using RADIUS Snooping
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Preconfiguring WAP Server Load Balancing
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Enabling Wireless Application Protocol SLB
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Configuring RADIUS Snooping
Using RADIUS Static Session Entries
RADIUS is a client/server protocol and software that enables remote access servers to commu-
nicate with a central server to authenticate dial-in users and authorize their access to the
requested network or service. RADIUS allows a company to maintain user profiles in a central
database that all remote servers can share. It provides better security, allowing a company to
set up a policy that can be applied at a single administered network point. RADIUS is an indus-
try standard used by network product companies and is a proposed IETF standard.
The RADIUS server uses a static session entry to determine which real WAP gateway should
receive the user’s sessions. Typically, each WAP gateway is integrated with a RADIUS server
on the same host, and a RADIUS request packet is allowed to go to any of the RADIUS
servers. Upon receiving a request from a client, the RADIUS server instructs the switch to
create a static session entry in the switch via Transparent Proxy Control Protocol (TPCP).