Design of p-Cycles for Full Node Protection

Design of p-Cycles for full node protection in WDM Mesh Networks

ABSTRACT:

We propose a p-cycle expanded protection scheme that can guarantee 100% node protection, in addition to 100% protection against single link failures. While some previous studies had already noted that p-cycles can naturally offer some node protection, we show that, at the expense of some p-cycle overlapping, with very mild impact on the bandwidth efficiency, we can guarantee node protection. We propose a design and solution method based on large scale optimization tools, namely Column Generation (CG), which compute p-cycles offering both link and node protection. Previous models offer a solution where a large number of potential cycles needs first to be enumerated, leading to very large ILP models which cannot scale. Comparisons are made between our proposed design approach and the work of Grover and Onguetou (2009). Results show that our approach clearly outperforms their design in terms of capacity efficiency and of the number of distinct cycles. We also evaluate the extra spare capacity requirement of p- cycles for full node protection compared to the one for link protection only. Results shows that p-cycles offering node and link protection only require a slightly larger spare capacity than conventional p-cycles while the implicit protection against a dual link failure is only marginally affected.

Existing System:

Algorithms for protection against link failures have traditionally considered Single- link failures. However, dual link failures are becoming increasingly important due to two reasons. First, links in the networks share resources such as conduits or ducts and the failure of such shared resources result in the failure of multiple links. Second, the average repair time for a failed link is in the order of a few hours to few days, and this repair time is sufficiently long for a second failure to occur. Although algorithms developed for single-link failure resiliency is shown to cover a good percentage of dual-link failures , these cases often include links that are far away from each other. Considering the fact

that these algorithms are not developed for dual-link failures, they may serve as an alternative to recover from independent dual-link failures. However, reliance on such approaches may not be preferable when the links close to one another in the network share resources, leading to correlated link failures.

Proposed System:

This paper formally classifies the approaches for providing dual-link failure resiliency. Recovery from a dual-link failure using an extension of link protection for single link failure results in a constraint, referred to as BLME constraint, whose satisfiability allows the network to recover from dual-link failures without the need for broadcasting the failure location to all nodes. The paper develops the necessary theory for deriving the sufficiency condition for a solution to exist, formulates the problem of finding backup paths for links satisfying the BLME constraint as an ILP, and further develops a polynomial time heuristic algorithm. The formulation and heuristic are applied to six different networks and the results are compared. The heuristic is shown to obtain a solution for most scenarios with a high failure recovery guarantee, although such a solution may have longer average hop lengths compared with the optimal values. The paper also establishes the potential benefits of knowing the precise failure location in a four-connected network that has lower installed capacity than a three-connected network for recovering from dual-link failures.

HARDWARE REQUIREMENTS

• 
  SYSTEM                                                
  
• HARD DISK
  
• MONITOR
  
• MOUSE
  
• RAM
  
• KEYBOARD
  

: Pentium IV 2.4 GHz : 40 GB
: 15 VGA colour : Logitech.
:256MB
: 110 keys enhanced.

SOFTWARE REQUIREMENTS

 Operating system :  FrontEnd :
 Tool :
REFERENCE:

Windows XP Professional JAVA
NETBEANS IDE

Brigitte Jaumar, Honghui Li, “Design of p-Cycles for full node protection in WDM Mesh Networks”, IEEE ICC 2011. 


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