Abstract
We investigate the survivable traffic-grooming problem for optical mesh
networks employing wavelength-division multiplexing (WDM) and dedicated protection.
We consider the dynamic-provisioning environment in which a connection arrives at
random, holds for a random amount of time, and then departs. A typical connection
request may require bandwidth less than that of a wavelength, and it may also
require protection from network failures, typically fiber cuts. On the basis of
generic grooming-node architecture, we propose two
approaches--protection-at-lightpath (PAL) level and protection-at-connection (PAC)
level--for grooming a connection request. Here we investigate dedicated protection.
In a companion paper [IEEE J. Sel. Areas Commun. 21, 1367 (2003)], we investigate
shared protection, which leads to a substantially different treatment. For dedicated
protection, we prove that the problem of provisioning a connection under PAC is
NP-complete, propose effective heuristics for both schemes, and define comprehensive
performance metrics to compare PAL with PAC with respect to wavelength or
grooming-port efficiency. Our findings are as follows. Under today's typical
connection-bandwidth distribution in which lower-bandwidth connections outnumber
higher-bandwidth connections, PAC outperforms PAL (in terms of bandwidth-blocking
ratio, lightpath use, and wavelength use) if the number of grooming ports is large;
however, PAL outperforms PAC (in terms of bandwidth-blocking ratio and grooming-port
use) when the number of grooming ports is moderate or small.
© 2003 Optical Society of America
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