An H.323 gatekeeper prototype: Design, implementation, and performance analysis
Journal
IEEE Transactions on Multimedia
Journal Volume
6
Journal Issue
6
Pages
936-946
Date Issued
2004-12
Date
2004-12
Author(s)
DOI
246246/200611150121643
Abstract
In recent years, Internet telephony or voice-over IP
is attracting an increasing amount of attention for the reason that
it has the potential to significantly reduce the cost of long-distance
voice communication. To provide the interoperability
between different manufacturers and vendors, ITU-T is actively
drawing up the standard for the Internet telephony as ITU-T
Recommendation H.323. While H.323 is continuously revised,
there are, however, still many important issues needed to be
further discussed. In particular, the bandwidth management,
address translation, and intelligent call signaling/routing, which
are the major functions of an H.323 gatekeeper, have not yet
been fully addressed. In view of this, we develop in this paper an
H.323 gatekeeper prototype which fully complies with the H.323
recommendation, and explicitly illustrate the usefulness of this
prototype by devising two improved call-routing methods to deal
with the load-balancing problem among the gatekeepers. As a
matter of fact, the existing call-routing method used in the current
version of the H.323 is very primitive and will cause the loads
of the gatekeepers unbalanced. Using the gatekeeper prototype
devised, two improved call-routing methods are proposed based on
Multiple-Registration with Multicasted Location Request (MRML)
and Multiple-Registration with Hierarchical Database (MRHD).
To evaluate the performance improvement by these two load-balancing
methods, we design an event-driven simulator and conduct
some experiments on it. We focus on two performance metrics,
call-blocking rate and channel utilization, which are both sensitive
to the load distribution. The experimental results show that the
call-blocking ratio and channel utilization are optimized with the
proposed load-balancing methods. It is also observed from our
empirical results that the call-blocking ratio is more sensitive to
the traffic load whereas the channel utilization is more sensitive to
the duration of a call.
Subjects
Communication system signaling
ITU
Protocol
teleconferencing
traffic control (communication)
Other Subjects
Internet; Interoperability; Network protocols; Routers; Signal processing; Telecommunication; Telecommunication traffic; Teleconferencing; Channel utilization; Communication system signaling; ITU; Multicasted location request (MRML); Software prototyping
Publisher
Taipei:National Taiwan University Dept Elect Engn
Type
journal article
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