NDLI: Strictly Nonblocking WDM Cross-connects

Please wait, while we are loading the content...

Strictly Nonblocking WDM Cross-connects

Content Provider	Society for Industrial and Applied Mathematics (SIAM)
Author	Wilfong, Gordon Rasala, April
Copyright Year	2005
Abstract	Using (WDM) technology, an optical network can route multiple signals simultaneously along a single optical fiber by encoding each signal on its own wavelength. If the network contains places where multiple fibers connect together and signals are allowed to be moved from any of the incoming fibers to any of the outgoing fibers, then the network is said to contain cross-connects. More precisely, a $k_1\,\times\,k_2$ WDM cross-connect has k1 input fibers and k2 output fibers. Each of the k1 input fibers supports the same n1 input wavelengths and each of the k2 output fibers supports the same n2 output wavelengths. Since a signal on input wavelength $\lambda$ can be routed from its input fiber to an output fiber such that it arrives on the output fiber using wavelength $\gamma$, where $\lambda \neq \gamma$, the cross-connect must be capable of performing wavelength conversion. Along any fiber in the cross-connect a device called a wavelength interchanger can be inserted to perform wavelength conversion. In other words if the path of a signal from an input fiber to an output fiber passes through a \wins, then the wavelength of the signal can be changed to any wavelength that is not already in use along the fiber leaving the wavelength interchanger. Given the high cost of \wisns, the overall cost of a \CC{k_1}{k_2} is minimized by reducing the number of \wis in the cross-connect. However, a desirable property for a cross-connect C is for C to always be able to provide a route (and wavelength conversion) for any valid demand from any pair of input and output fibers regardless of the routes of other demands currently routed in C. If C has this capability then it is said to be strictly nonblocking. For most of this paper we consider a demand to be a request for a connection from an input fiber to an output fiber such that the connection starts on a specified input wavelength and leaves the on a second specified wavelength. Using this demand model, we consider cross-connects for which $k_1$ is not necessarily equal to $k_2$ and the number $n_1$ of supported input wavelengths can differ from the number $n_2$ of supported output wavelengths. Without loss of generality we assume that $k_1 \leq k_2$ and present a family of \snob \CCns{k_1}{k_2}s that use \Opt \wisns. For the case when $k_1 = k_2=k$ and $n_1 = n_2$, we prove that this is optimal. For s where $n_1$ is not necessarily equal to $n_2$, we show that if there is at most one wavelength interchanger on any path from an input fiber to an output fiber, \Opt \wis are optimal. Finally, we consider a more flexible demand model where $k_1 = k_2$ but the input and output wavelengths are not specified as part of the demand. We show that $2k-1$ \wis are still necessary for any \snob \CC{k}{k}.
Starting Page	449
Ending Page	485
Page Count	37
File Format	PDF
ISSN	00975397
DOI	10.1137/S0097539703434255
e-ISSN	10957111
Journal	SIAM Journal on Computing (SMJCAT)
Issue Number	2
Volume Number	35
Language	English
Publisher	Society for Industrial and Applied Mathematics
Publisher Date	2006-07-27
Access Restriction	Subscribed
Subject Keyword	wavelength division multiplexing strictly nonblocking optical networking cross-connect Network design and communication Communication networks
Content Type	Text
Resource Type	Article
Subject	Mathematics Computer Science

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in