13-11-2012, 02:13 PM
Exploiting Excess Capacity to Improve Robustness of WDM Mesh Networks
ABSTRACT
Excess capacity (EC) is the unused capacity in a network.
We propose EC management techniques to improve
network performance. Our techniques exploit the EC in
two ways. First, a connection pre provisioning algorithm
is used to reduce the connection setup time. Second,
whenever possible, we use protection schemes that have
higher availability and shorter protection switching time.
Specifically, depending on the amount of EC available in
the network, our proposed EC management techniques
dynamically migrate connections between highavailability,
high-backup-capacity protection schemes and
low-availability, low-backup-capacity protection
schemes. Thus, multiple protection schemes can coexist
in the network. The four EC management techniques
studied in this paper differ in two respects: when the
connections are migrated from one protection scheme to
another, and which connections are migrated.
Specifically, Lazy techniques migrate connections only
when necessary, whereas Proactive techniques migrate
connections to free up capacity in advance. Partial
Backup Reprovisioning (PBR) techniques try to migrate a
minimal set of connections, whereas Global Backup
Reprovisioning (GBR) techniques migrate all
connections. We develop integer linear program (ILP)
formulations and heuristic algorithms for the EC
management techniques. We then present numerical
examples to illustrate how the EC
management techniques improve network performance
by exploiting the EC in wavelength-division-multiplexing
(WDM) mesh
networks.