Information Technology Reference
There are algorithms to protect the unicast traffic detailed in this chapter as: Dynamic hop
constrained sub-path protection, Partial SRLG-disjoint shared path protection with
differentiated reliability, two-segment algorithm, WDM-shared-non-SRLG Protection, on-
line hybrid survivability, survivable algorithm named sub-path protection based on auxiliary
virtual topology, Ant-based survivable routing, recursive shared segment protection, Network
Coding, and Level of Service Algorithm. Moreover, there is a set of algorithms proposed for
protecting multicast traffic, e.g., Optimal Path-Pair based Removing Residual Link removes
the residual links in the process of finding the path-pair for a destination node. The other
algorithm is Source-Leaf Path based Avoiding Residual Link Algorithm, the Multicast
Protection through Spanning Paths algorithm, the Adaptive Share Segment Protection, the
Shared Source-Leaf Path based Protection algorithm, the primary tree in spares-splitting
WDM networks, Sparse Splitting constrained Multicast Protection, Cross-sharing algorithm,
Arc-disjoint tree with differentiated reliability, Partial tree protection, Segment Protection
with Most-likely Failure Link, and tree protection scheme with optimized shortest path tree.
In general, we aim to review the recent protection schemes suitable for WDM mesh
networks. We focus on the protection schemes supporting unicast traffic and the protection
schemes supporting multicast traffic in such networks. Since it may not be possible to
compare all the protection schemes with each other due to the inherent implementation, we
provide a comparison among different techniques of the same group.
In Section 2, we introduce basic protection techniques. In Section 3, unicast protection
schemes are studied. Multicast protection schemes are reviewed in Section 4. To insight on
suitable protection schemes, we compare protection schemes with respect to their parameters
such as network complexity and blocking percentage in Section 5. The summery of this
review is given in Section 6.
2. B ASIC P ROTECTION T ECHNIQUES
The basic protection schemes proposed for WDM mesh networks shall be reviewed in
this section. Then, the protection techniques which have been proposed to protect unicast and
multicast traffic will be reviewed in future sections.
Link protection scheme is based on the routing of all connections around a failed link.
When a call request is accepted, the link protection scheme will save network resources for
related path protection. Take a notice that two nodes adjoining to a failed link must be
connected by a protection path (see Figure1) .
When a link failure takes place, the node adjacent to the upstream of the failed link
immediately redirects the traffic along the predetermined protection path to the failed link to
restore transmission . In fact, end nodes of the failed link are responsible for rerouting of
affected traffic around failure without informing the source and destination nodes . In this
scheme, the reservation of the protection resource is accounted for each link.