Photonic Network Communications, 6:2, 105±117, 2003
# 2003 Kluwer Academic Publishers. Manufactured in The Netherlands.
Design and Performance Evaluation of a Separated Control Signaling
Protocol for WDM Optical Networks
Division of Computer, Electronics and Communication, Kwangju University, 503±703, Korea
Su-Hyun Kim, In-Kon Kang, Young-Chon Kim
Department of Computer Engineering, Chonbuk National University
E-mail: firstname.lastname@example.org, ®re¯email@example.com, firstname.lastname@example.org
Department of Computer Science, University of California, Davis
Received July 10, 2002; Revised February 19, 2003; Accepted February 20, 2003
Abstract. In WDM optical networks, an ef®cient control signaling protocol is required to dynamically establish lightpaths. This paper proposes
a separated control signaling protocol (SCSP) and compares the performance of SCSP with a conventional integrated control signaling protocol
(ICSP). The conventional ICSP makes reservations sequentially from the source to the destination for setting up and tearing down lightpaths. It
increases the control overhead and wastes the network resource if it cannot reserve the network resource at an intermediate node. Speci®cally, if
the receiver at the destination is not available after successful reservation at intermediate nodes, it wastes a lot of bandwidth. It causes decreasing
chances of reservation for other lightpaths. Instead, SCSP separates bearer control from call control to reduce the waste of network resources.
The call control function checks the availability of network resources such as wavelengths and receivers. Bearer control reserves, allocates, and
releases network resources. To evaluate the performance of the two protocols, they are mathematically analyzed using a probabilistic model.
Simulation results are also provided to compare the proposed protocol with the conventional ICSP in terms of utilization and blocking
probability. From the results of simulation and iterative analysis, we can observe that SCSP performs better than ICSP.
Keywords: WDM, signaling protocol, call, bearer, optical network
Recently, wavelength division multiplexing (WDM)
is considered as a promising technology to meet the
enormous bandwidth requirements of end-users . A
lightpath is an optical path (data channel) established
between two nodes. In WDM optical networks, a
lightpath is usually established before data is
transferred between two communicating nodes.
In the beginning, WDM optical networks provided
lightpaths that support slow-changing or static
service. However, since the Internet traf®c has
doubled every three to four months, most applications
require to dynamically establish lightpaths to support
stringent QoS. Therefore, in response to this growth,
WDM optical networks should provide the capability
of a direct lightpath among edge nodes and it needs
control signaling protocols to establish lightpaths
ef®ciently for the various traf®c demands.
Establishing a lightpath involves selecting a route
and a wavelength for a given connection request and
reserving of the required resources along that route.
There are two basic approaches that can be used to
select wavelengths to establish a lightpath: path
multiplexing (PM) and link multiplexing (LM). PM
establishes a lightpath using the same wavelength
from the source to the destination. If the intermediate
nodes have a wavelength conversion capability, a