Multicast Routing and Wavelength Assignment for Capacity Improvement in Wavelength Division Multiplexing Networks by ijcsis

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									                                                          (IJCSIS) International Journal of Computer Science and Information Security,
                                                          Vol. 8, No. 7, October 2010




    Multicast Routing and Wavelength Assignment for
     Capacity Improvement in Wavelength Division
                 Multiplexing Networks

                        N.Kaliammal                                                                 G.Gurusamy
              Professor, Department of ECE,                                                     Prof/Dean/ EEE, FIE
       N.P.R college of Engineering and Technology,                                    Bannari amman Institute of Technology,
                   Dindugul, Tamil nadu                                                    Sathyamangalam,Tamil nadu.
             Email: kala_gowri@yahoo.co.in                                                 E-mail: hodeee@bitsathy.ac.in
                   Tel: +91 9965557267                                                          Tel: +91 9791301662


Abstract—In WDM network, the route decision and wavelength                 amount of data at high speeds by the users over large distance
assignment of light-path connections are based mainly on the               [2].
routing and wavelength assignment (RWA). The multicast
routing and wavelength assignment (MC-RWA) problem is for                      For the future generation internet, WDM is considered as a
maximizing the number of multicast groups admitted or for                  backbone which is the most talented technology. The data is
minimizing the call blocking probability. In this paper, The               routed through optical channels called light paths in WDM all
design of multicast routing and wavelength assignment technique            optical networks. The light path establishment requires same
for capacity improvement in wavelength division multiplexing               wavelength and it should be used along the entire route of the
(WDM) networks is proposed. In this technique, the incoming                light path without wavelength conversion. This is commonly
traffic is sent from the multicast source to a set of intermediate         considered to the wavelength continuity constraint [3].
junction nodes and then, from the junction nodes to the final
destinations. The traffic is distributed to the junction nodes in          B. Multicasting in WDM Networks
predetermined proportions that depend on the capacities of                     A network technology which is used for the delivery of
intermediate nodes. Then, paths from source node to each of the            information to a group of destinations is called as multicast
destination nodes and the potential paths are divided into                 addressing. This simultaneously uses the most efficient
fragments by the junction nodes and these junction nodes have              strategy to deliver the message over each link of the network
the wavelength conversion capability. By using the concept of              only once. Moreover, it creates the copies only when the links
fragmentation and grouping, the proposed scheme can be                     to the multiple destinations split [4].
generally applied for the wavelength assignment of multicast in
WDM network. By simulation results, it is proved that ther                     In recent years, multicast communication is turning out to
proposed technique achieves higher throughput and bandwidth                be vital due to its efficient resources usage and the increasing
utilization with reduced delay.                                            popularity of the point-to-multipoint multimedia applications.
                                                                           Usually, a source and a set of destinations are included in a
                         I. INTRODUCTION                                   multicast session. In conventional data networks, in order to
A. Wavelength-Division-Multiplexing (WDM) Networks                         allow a multicast session, a multicast tree which is rooted at
                                                                           the source is constructed with branches spanning all the
    The need for on-demand provisioning of wavelength                      destinations [5].
routed channels with service differentiated offerings within the
transport layer has become more essential due to the recent                    Recently, multicast routing in optical networks has been
emergence of high bit rate IP network applications. Diverse                researched which is related to the design of multicast-capable
optical transport network architectures have been proposed in              optical switches. For multicast in WDM networks, the concept
order to achieve the above requirements. This approach is                  of light-trees was introduced. Reducing the distance of
determined by the fundamental advances in the wavelength                   network-wide hop and the total number of transceivers used in
division multiplexing (WDM) technologies. Due to the                       the network are the objective of setting up the light trees.
availability of ultra long-reach transport and all-optical                 Nowadays, there are several network applications which
switching, the deployment of all-optical networks has been                 require the support of QoS multicast such as multimedia
made possible [1].                                                         conferencing systems, video on demand systems, real-time
                                                                           control systems, etc. [6].
    The concurrent transmission of multiple streams of data
with the assistance of special properties of fiber optics is               C. Routing and Wavelength in WDM
called as wavelength division multiplexing (WDM). The                          In WDM network, the route decision and wavelength
WDM network provides the capability of transferring huge                   assignment of light-path connections are based mainly on the
                                                                           routing and wavelength assignment (RWA). This is the most



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                                                                                                      ISSN 1947-5500
                                                           (IJCSIS) International Journal of Computer Science and Information Security,
                                                           Vol. 8, No. 7, October 2010



important and basic issue in resource management. For                        are divided into fragments by the junction nodes and these
maximizing the number of multicast groups admitted or for                    junction nodes have the wavelength conversion capability. By
minimizing the call blocking probability with certain number                 using the concept of fragmentation and grouping, the proposed
of wavelengths, the multicast routing and wavelength                         scheme can be generally applied for the wavelength
assignment (MC-RWA) problem is studied. [7].                                 assignment of multicast in WDM network. The Least
                                                                             Influence Group (LIG) approach is used to provide the
   The problem of finding a multicast tree and allocating
                                                                             wavelength selection.
available wavelength for each link of the tree is known as the
Multicast Routing and Wavelength Assignment (MC-RWA)                                                II. RELATED WORK
problem, which plays a key role in supporting multicasting
over WDM networks [8]. The problems involving in the                             Jingyi He et al [7] have proposed for the first time a
routing and wavelength assignment in WDM are as follows:                     formulation of the MC-RWA problem with the objective to
                                                                             maximize the number of multicast groups admitted, or
    •     Improper wavelength assignment, especially for the                 equivalently, to minimize the call (or session) blocking
          multicast connection, will cause wavelength                        probability given a certain number of wavelengths.. The
          blocking, whereas the network resources may be still               formulation is a nonlinear integer program, which in general is
          underutilized.                                                     complex to solve so a near-optimal solution of the problem is
     • The wavelength continuity constraint, i.e., that links                proposed using a two-step approach based on linear
          from source to destination shall use the same                      programming. The drawback in this work is that the focus is
          wavelength to convey data in the same lightpath,                   on minimizing the user blocking probability instead of the
                                                                             session blocking probability for single-source applications.
          always makes the wavelength assignment inflexible
          and causes wavelength blocking.                                        Anping Wang et al [8] have proposed a new multicast
     • The available wavelength can be maximized by the                      wavelength assignment algorithm called NGWA with
          wavelength converter but this type of device is much               complexity of O(N), where N is the number of nodes on a
          intricate and cost is also high when compared with                 multicast tree. The whole procedure of NGWA algorithm is
          the type of device which cannot perform the                        separated into two phases: the partial wavelength assignment
          conversion.                                                        phase and the complete wavelength assignment phase. The
     • The signal may also decay during the conversion.                      drawback of this work is that this method achieves only
                                                                             satisfactory performance in terms of the total number of
          Therefore, it is not possible to have all network nodes
                                                                             wavelength conversions and the average blocking probability
          be equipped with wavelength conversion capability.
     • The problem of the node architecture is that they                         Nina Skorin-Kapov [10] has addressed the problem of
          were designed without having into account power                    multicast routing and wavelength assignment (MC RWA) in
          efficiency, neither complexity of fabrication [9].                 wavelength routed WDM optical networks. Multicast requests
     • The two sub-problems of the routing and wavelength                    are facilitated in WDM networks by setting up so-called light-
          assignment are the routing problem and the                         trees and assigning wavelengths to them. She has proposed a
          wavelength assignment problem, which can be either                 heuristic algorithm based on bin packing methods for the
                                                                             general MC RWA problem, which is NP-complete. These
          coupled or uncoupled. In the case of uncoupled
                                                                             algorithms can consider unicast, multicast and broadcast
          situation, initially a route or a tree is obtained which           requests with or without QoS demands. Computational tests
          is then followed by the wavelength assignment where                indicate that these algorithms are very efficient, particularly
          the trees must be kept unchanged and is called as the              for dense networks.
          static RWA. In the coupled case, based on the state
          of the wavelength assignment, the routes are decided                   Fen Zhou et al [11] have proposed a routing and
          which is usually called as dynamic or adaptive RWA                 wavelength assignment for supporting multicast traffic is
          [7].                                                               investigated in WDM mesh networks under sparse splitting
    In previous paper, a resource efficient multicast routing                constrain. This problem is generally solved in two phases
protocol is developed. In this protocol, the incoming traffic is             respectively with the purpose of minimizing the number of
sent from the multicast source to a set of intermediate junction             wavelengths required. Alternative routing is first proposed to
nodes and then, from the junction nodes to the final                         route each session by pre-computing a set of candidate light-
destinations. The traffic is distributed to the junction nodes in            forests. Then wavelength assignment is formulated as coloring
predetermined proportions that depend on the capacities of                   problems by constructing a conflict graph. Potential heuristic
intermediate nodes. Bandwidth required for these paths                       algorithms are proposed. The drawback of this work is that
depends on the ingress–egress capacities, and the traffic split              simulation should be done to assess the verification of the
ratios. The traffic split ratio is determined by the arrival rate of         proposed methods.
ingress traffic and the capacity of intermediate junction nodes                  Yuan Cao et al [12] have proposed an efficient QoS-
[13].                                                                        guaranteed Group Multicast RWA solutions, where the
    In this paper, a multicast routing and wavelength                        transmission delay from any source to any destination within a
assignment technique in wavelength division multiplexing                     multicast group is within a given bound. They have formulated
networks is designed. In this technique, paths from source                   the QoS-guaranteed GMC-RWA problem as an in-group
node to each of the destination nodes and the potential paths                traffic grooming and multicasting problem, where traffic




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                                                                                                        ISSN 1947-5500
                                                         (IJCSIS) International Journal of Computer Science and Information Security,
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streams from members of the same group are groomed in an                                                   D.
effective way before being delivered to their common                                                   1.2 End if
destinations, subject to the following optical layer constraints.                     2. End for
                                                                                      3. If {D} ≠ Null, Then
                III. MULTICAST TREE FORMATION
                                                                                                    3.1 Repeat from1.
A. Basic Definitions                                                                  4. End if
    The node which cannot split the incoming message to the
outgoing ports is called as Multicast Incapable (MI) nodes.               B. Multicast Routing
But it can utilize a small amount of optical power from the
wavelength channel while forwarding it to only one output                     A collection of point to multiple point paths from the
link.                                                                     source node to each destination is considered as a multicast
                                                                          tree. Choosing a suitable wavelength for its downlink is
   The nodes which are capable of splitting the incoming                  flexible for a path in the WDM network which has sparse
message to all the outgoing ports are called as Multicast                 junction nodes. The main objective is to reduce the affected
Capable (MC) nodes.                                                       capacity. This can be done by selecting a suitable wavelength
                                                                          for the downlink of the junction nodes which reduces the
    The set which includes the multicast capable nodes (MC
                                                                          influence on the potential request paths across it. The junction
node) and the leaf multicast incapable nodes (leaf MI nodes) is
                                                                          node is considered as an end point of a wavelength within a
called as MC_SET.
                                                                          fragment. According to the position of converters within the
   The set which includes only the non-leaf multicast                     path, the path can be divided into uni-wavelength fragments.
incapable nodes, which are not able to connect a new                      As a result, paths from source node to each of the destination
destination to the multicast tree, is called as MI_SET.                   nodes and the potential paths are divided into fragments by the
                                                                          junction nodes and these junction nodes have the wavelength
   The set D includes the unvisited multicast destinations                conversion capability.
which are not yet joined to the multicast tree.
                                                                             A network G= (N, E) with node set N and (directed) edge
    A constraint path between a node u and a tree T is a                  E set is taken,where each node in the network can be a source
shortest path from node u to a node v in the MC_SET for T,                or destination of traffic. The nodes in N are {N1, N2…Nn}.
and this shortest path should not traverse any node in MI_SET
for T. And the constraint path with the minimum length is                                         S
called the Shortest Constraint Path (SCP).                                                R1            0
    For one nearest destination d, MC_SET may have different
SCPs to the sub-tree. Let X and Y are the nodes for the sub-
tree in MC_SET. Without involving any node in MI_SET for                                    1                    2
the sub-tree, both the shortest paths from X and Y to the                    R2
nearest destination d have the shortest length among all the
nodes in MC_SET. Here, the nodes like X and Y are named as                                                                             Junction
junction nodes in the sub-tree.                                                                                                        Node
                                                                                  3                    4
   Member only Algorithm
      T = {s}
       MI_SET = Null                                                                            Figure 1. Multicast Routing Process
       MC_SET = {s}
       D = {D1, D2….Dn}                                                       The above diagram (Fig. 1) shows the routing process. A
       1. For each Di, where i = 1, 2….n                                  predetermined fraction of the traffic entering the network at
                                                                          any node is distributed to every junction node. The
                1.1 If dist (Di, N) = min, where N ∈
                                                                          corresponding route from the source to the junction node can
                 MC_SET, then                                             be denoted as R1. Then each junction node receives the traffic
                          1.1.1 Add Di to T                               to be transmitted for different destinations and it routes to their
                          1.1.2 Find SCP (Di, T) ∉ M, where               respective destinations. The corresponding route from the
                          M ∈ MI_SET                                      junction node to the destination can be denoted as R2.
                          1.1.3 Add SCP (Di, T) to T
                          1.1.4 Add all the MC nodes to                       Let Ii and Ei, be the constraints on the total amount of
                          MC_SET                                          traffic at ingress and egress nodes of the network, respectively.
                          1.1.5 Add all the leaf MI nodes to                  The traffic along R1 and R2 must be routed along
                          MC_SET                                          bandwidth-guaranteed paths. Bandwidth required for these
                          1.1.6 Add all the non-leaf MI nodes             paths depends on the ingress–egress capacities, and the traffic
                          to MI_SET                                       split ratios. The traffic split ratio (δ) is determined by the
                          1.1.7 Delete the non - leaf MI node             arrival rate of ingress traffic and the capacity of intermediate
                          from MC_SET                                     junction nodes.
                          1.1.8 Delete the destination di from



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                                                                                 where Pij is the jth fragment of the potential path i, Si is the
     The bandwidth requirement for the routing paths R1 and                  source node of the potential path i, and Di is the destination of
R2 is derived. Consider a node i with maximum incoming                       the potential path i. Basically, each fragment can be treated as
traffic Ii. Node i sends δjIi amount of this traffic to node j               a reassignment domain of wavelength.
during R1 routing for each jєN and thus the traffic demand is
                                                                                 Fragments of a path are mutually independent from the
δjIi. Now, node i has received δiIk traffic from any other node
                                                                             wavelength assignment point of view and may be with
k. Out of this, the traffic destined for node j is δirkj since all
                                                                             different fragment capacities. The actual capacity of a path is
traffic is initially split without regard to the final destination.
                                                                             basically determined by its fragment(s) with the least capacity.
The traffic that needs to be routed from node i to node j at R2
                                                                             The fragment(s) with the least capacity of a path is named the
routing is given below:
                                                                             critical fragment of that path. Let CPi and CPPi be the path

                     ∑δ r
                                                                             capacity (the least fragment capacity) of the path i of the
                             i kj   ≤ δi E j .                               multicast tree, and the path capacity of the potential path i,
                     k∈N                                                     respectively,then
    Thus, the traffic demands from node i to node j at the end                                                                                        (3)
of R2 routing is λiEj.                                                                       CPi =    min            SCPR i j
                                                                                                     1≤ j ≤ ri + 1
    Hence, the maximum demand from node i to node j as a                     and
result of R1 and R2 routing is δjIi + δiEj.
                                                                                                           CPpi = min SCPpi
                                                                                                                                        j
    Let M = [mij] = [δjIi + δiEj] be the fixed matrix which can                                                                                       (4)
handle the traffic variation. It depends only on aggregate                                                               1≤ j ≤ ri +1
ingress-egress capacities and the traffic split ratios δ1, δ2 …. δn,             Capacity of the path cannot be decreased by decreasing the
Thus the routing scheme is unaware to the changes in traffic                 capacity in a fragment whose capacity is larger than the
distribution.                                                                critical fragment of that path. A path may have more than one
                                                                             critical fragment. Let Fi = {fi1, fi2 …} be the set of the critical
           IV. MULTICAST WAVELENGTH ASSIGNMENT                               fragments in the potential path i. Then Fi can be used to
A. Grouping the Paths                                                        indicate whether the potential path is affected or not during the
                                                                             wavelength assignment of the multicast tree. So, the critical
    Assume the set Ri = {Ri1, Ri2 … Rij …} to represent all
                                                                             fragment of a potential path is the fragment traveled by the
fragments of the path from source to the ith destination in the
                                                                             multicast tree. The impact on the potential path can be reduced
multicast tree. Rij is the jth fragment of the path i. If AWRij is
                                                                             by considering the wavelength assignment of that fragment
the set of available wavelengths of the jth fragment of path i,
                                                                             carefully. Fragments which come from multicast tree with
then the number of wavelengths in AWRij is regarded as the
                                                                             common links into groups are coupled using the concept of
capacity of this fragment. The capacity of the jth fragment of
                                                                             grouping. Within a group, all fragments have common
the path i, SCPRij is obtained as
                                                                             wavelengths. As a result a group is composed of fragments
         ⎧OL ( S , J k ) =| AWR j |,                                         whose links are overlapped.
                    i          i       k = 1, j = 1
         ⎪
      j ⎪         k     k −1         j                                              G = {G1, G2… Gm… GY}                                 (5)
SCPR i = ⎨OL ( J i , J i ) =| AWRi |, 1 < k ≤ M i , j = k                        where G is the set of all groups in a multicast tree, Gm is
         ⎪        k              j                                           the set of all fragments in the mth group.
         ⎪OL ( J i , D ) =| AWRi |,
         ⎩
                                       k = Mi, j = Mi +1
                                                          (1)                    The multicast tree with n destinations is treated as n
                                                                             unicast paths from source to each destination. Paths are
    where s is the source node of the multicast tree, Di is the ith          fragmented with respect to junction nodes. Same group
destination of the multicast tree, Jik is the kth wavelength                 fragments have more than one available wavelength in
converter in the path i, and Mi + 1 is the number of fragments               common. Let AWGm be the connection set of all fragments
of path i if there are Mi junction nodes being traveled by the               existing wavelengths in the mth group. The group capacity,
path. The Overlap function OL(n1, n2) represents the size of                 CGm, is defined as the number of wavelengths in AWGm. If
the intersection set of all available wavelengths for all links              links of a fragment and the links in the mth group are
from node n1 to n2.                                                          overlapped and no common available wavelength between
                                                                             them, this fragment will be considered as a new group.
    For the potential request paths, the set Pi = {pi1, pi2 …}is
defined to indicate all fragments of the ith potential request               B. Total Network Capacity Estimation
path and the capacity of the jth fragment of the potential path i,               The influence of network capacity is examined by
SCPPij, can be stated as following                                           checking whether the links of potential paths overlap with
                                                                             those of the multicast groups. If the overlap occurs at the
             ⎧OL ( S , J k ),          k = 1, j = 1
             ⎪            i                                                  critical fragments of the potential path and the assigned
             ⎪                                                               wavelength is the one of the available wavelengths in that
   SCPPi j = ⎨OL ( J i k , J i k −1 ), 1 < k ≤ M i , j = k      (2)
                                                                             critical fragment, the path capacity of the potential path will be
             ⎪         k                                                     affected. Let Cm(pi, λ) be the capacity of pi being influenced
             ⎪OL ( J i , D ),          k = Mi, j = Mi +1
             ⎩                                                               when the wavelength λ is assigned in the mth group, and x be a




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common link of the mth group and the critical fragment of the
potential path i. Then
                                                                                           TNC m ,λ =      ∑C
                                                                                                           p b ∈P '
                                                                                                                      m   ( pb , λ )

                  ⎧1 if (λ ∈ xw ) ∧ x ∈ LS m , Fi                               3.   Assign λ which TNCm, λ is minimum in group m
  Cm ( pi , λ ) = ⎨                                             (6)
                  ⎩0 Otherwise                                                                  V. SIMULATION RESULTS
    where LSm,Fi = LGm ∩ LFi, LGm is the set of all links in the            A. Simulation Model and Parameters
mth group, LFi is the set of all links in the critical fragments of
the potential path i. and xw is the set of all available                        In this section, the performance of multicast routing and
wavelengths on link x.                                                      wavelength assignment technique is simulated with an
                                                                            extensive simulation study based upon the ns-2 network
    The network capacity affected when λ is assigned for the                simulator [14]. The Optical WDM network simulator (OWNs)
mth group, TNCm,λ , can be obtained by the summation of the                 patch in ns2 is used to simulate a NSF network (Fig.1) of 14
influence of all potential paths as                                         nodes. Various simulation parameters are given in table I.
               TNCm,λ =       ∑ Cm ( pi , λ )                   (7)
                             pi ∈P
    The total network capacity (TNC) gets affected since each
group should assign one wavelength, and it can be obtained by
the summation as

              TNC =      ∑ ∑ Cm ( pi , λm ) − q                 (8)
                        All m pi ∈P
                                                                                             Figure 1. NSF network of 14 nodes
    In the mth group, λm is the wavelength assigned and q is the
affected capacity that is counted repeatedly. This can be                                   TABLE I: SIMULATION PARAMETERS
regained in the first term of (8). When the same wavelength is
assigned to the groups it leads to repeated counts and also the                Topology                                     Mesh
critical fragments of the path travels through the group. For                  Total no. of nodes                           14
example, the available wavelengths of the critical fragment of                 Link Wavelength Number                       8
potential path p1 are (λ1, λ2). G1 and G2 are the groups of the                Link Delay                                   10ms
multicast tree. If λ1 is assigned to G1 and G2 and if the critical             Wavelength Conversion Factor                 1
fragment of potential path p1 travels through G1 and G2, then,
according to the first term of (8), the affected capacity of p1 is             Wavelength Conversion Distance               8
calculated twice. In fact, the decreased capacity is only one.                 Wavelength Conversion Time                   0.024
The other repeated count happens when the same or a different                  Link Utilization sample Interval             0.5
wavelength is assigned to the groups and more than one                         Traffic Arrival Rate                         0.5
critical fragment of an individual path goes through these                     Traffic Holding Time                         0.2
groups.                                                                        Packet Size                                  200
C. Wavelength Assignment                                                       No. of Receivers                             4
                                                                               Max Requests Number                          50
    By using junction nodes the multicast tree is separated into               Rate                                         2,4,6, 8 and 10 Mb
groups, so the wavelength assignments for groups are
independent of each other. The wavelength assigned in the                      Number of Traffic Sources                    1,2,3,4 and 5
previous group has no effect on the wavelength assigned in the
current group. The wavelength assigned for each group can be                   In this simulation, a dynamic traffic model is used, in
easily selected since all of the available wavelengths for a                which connection requests arrive at the network according to
group have been collected in AWGm.                                          an exponential process with an arrival rate r (call/seconds).
                                                                            The session holding time is exponentially distributed with
    The Least Influence Group (LIG) algorithm selects the                   mean holding time s (seconds).
wavelengths for groups to maximize the network capacity.
The idea behind LIG algorithm is that the wavelength having                    The connection requests are distributed randomly on all the
the least effect on the potential paths is chosen for that group.           network nodes. In all the simulation, the results of MRWA
The affected network capacity in (7) examines the influence of              with the previous paper “resource efficient multicast routing
each wavelength assignment. The LIG algorithm is illustrated                (REMR) protocol [13].” Is compared.
below:                                                                      B. Performance Metrics
                    AWGm = {λ1, λ2, λ3….}                                       In this simulation the blocking probability, end-to-end
    1.   Find all pb whose links overlap in the links of group              delay and throughput is measured.
         m
    2.   For each λ ∈ AWGm




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      •            Bandwidth Utilization: It is the ratio of bandwidth
                                                                                                                  Rate Vs Utilization
                   received into total available bandwidth for a traffic
                   flow.
      •            Average end-to-end delay: The end-to-end-delay is                                0.08
                   averaged over all surviving data packets from the




                                                                                      Utilization
                                                                                                    0.06
                   sources to the destinations.                                                                                                         MRWA
                                                                                                    0.04
      •            Throughput: It is the number of packets received                                                                                     REMR
                   successfully.                                                                    0.02

C. Results                                                                                            0
                                                                                                           2      4       6       8      10
A. Effects of Varying Traffic
    In the initial simulation, the traffic rate is varied as 2Mb,                                                      Rate(MB)
4Mb, 6Mb, 8Mb and 10Mb and measure the throughput, end-
to-end delay and bandwidth utilization.                                                                         Figure 4. Rate Vs Utilization

                                   Rate Vs Throughput                                  Figure. 2 shows the throughput occurred when the rate is
                                                                                   increased. From the figure, it is proved that the throughput is
                 1.5                                                               more in the case of MRWA when compared to REMR.
                                                                                       Figure.3 shows the end-to-end delay occurred when the
                  1                                               MRWA             rate is increased. It shows that the delay of MRWA is
                                                                  REMR
                                                                                   significantly less than the REMR.
                 0.5
                                                                                       Figure.4 shows the bandwidth utilization obtained when
                  0                                                                the rate is increased. MRWA shows better utilization than the
                           2       4         6       8     10                      REMR scheme.

                                       Rate(MB)
                                                                                   B. Effect of Varying Traffic
                                   Figure 2. Rate Vs Throughput
                                                                                      In this simulation , the number of traffic sources is varied
                                                                                   as 1, 2, 3, 4 and 5 and measure the throughput, end-to-end
                                                                                   delay and bandwidth utilization.
                                           Rate Vs Delay
                                                                                                               Traffic Vs Throughput
                 2000

                 1500                                                                               3500
    Delay(sec)




                                                                  MRWA                              3000
                 1000
                                                                                      Throughput




                                                                  REMR                              2500
                   500                                                                              2000                                                MRWA
                                                                                                    1500                                                REMR
                       0
                                                                                                    1000
                               2       4         6    8    10
                                                                                                     500
                                           Rate(MB)                                                    0
                                                                                                           1       2      3       4       5
                                       Figure. Rate Vs Delay                                                            Traffic


                                                                                                               Figure 5. Traffic Vs Throughput




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                                                                                        distributed to the junction nodes in predetermined proportions
                                    Traffic Vs Delay                                    that depend on the capacities of intermediate nodes. Then,
                                                                                        paths from source node to each of the destination nodes and
                   70                                                                   the potential paths are divided into fragments by the junction
                   60                                                                   nodes and these junction nodes have the wavelength
                   50                                                                   conversion capability. In order to select the wavelengths for
                                                                                        groups to maximize the network capacity, the Least Influence
     Delay




                   40                                                 MRWA
                   30                                                 REMR
                                                                                        Group (LIG) algorithm is used, i.e. the wavelength having the
                   20                                                                   least effect on the potential paths is chosen for that group. So
                   10                                                                   the affected network capacity influences the wavelength
                    0                                                                   assignment. By simulation results, it is proved that the
                                                                                        proposed technique achieves higher throughput(22% increase)
                         1      2       3       4       5
                                                                                        and bandwidth utilization (1% increase)with reduced
                                     Traffic                                            delay(420sec decrease)for varying rate & 9.4 sec derease in
                                                                                        delay ,0.3% increase in utilization and 480times increase in
                               Figure 6. Traffic Vs Delay                               throughput for varying traffic.
                                                                                                                       REFERENCE
                               Traffic Vs Utilization                                   [1]    A. Rajkumar and N.S.Murthy Sharma, “A Distributed Priority Based
                                                                                               Routing Algorithm for Dynamic Traffic in Survivable WDM Networks”,
                                                                                               IJCSNS International Journal of Computer Science and Network
                    1                                                                          Security, VOL.8 No.11, November 2008.
                   0.8                                                                  [2]    Canhui (Sam) Ou Hui Zang, Narendra K. Singhal, Keyao Zhu, Laxman
     Utilization




                                                                                               H. Sahasrabuddhe, Robert A. Macdonald and Biswanath Mukherjee,
                   0.6                                                MRWA                     “Sub path Protection For Scalability And Fast Recovery In Optical
                   0.4                                                REMR                     WDM Mesh Networks”, IEEE Journal On Selected Areas In
                                                                                               Communications, Vol. 22, No. 9, November 2004.
                   0.2                                                                  [3]    Vinh Trong Le, Son Hong Ngo, Xiao Hong Jiang, Susumu Horiguchi
                                                                                               and Yasushi Inoguchi, “A Hybrid Algorithm for Dynamic Lightpath
                    0                                                                          Protection in Survivable WDM Optical Networks”, IEEE, 2005.
                         1      2       3       4        5                              [4]    Multicasting: http://en.wikipedia.org/wiki/Multicasting
                                     Traffic                                            [5]    Fen Zhou, Miklos Molnar and Bernard Cousin, “Distance Priority Based
                                                                                               Multicast Routing in WDM Networks Considering Sparse Light
                                                                                               Splitting”, IEEE 11th Singapore International Conference on
                             Figure 7. Traffic Vs Utilization                                  Communication Systems – 2008
                                                                                        [6]    Xiao-Hua Jia, Ding-Zhu Du, Xiao-Dong Hu, Man-Kei Lee, and Jun Gu,
    Figure 5 shows the throughput occurred when varying the                                    “Optimization of Wavelength Assignment for QoS Multicast in WDM
number of traffic sources. From the figure it is proved that, the                              Networks”, IEEE Transactions on Communications, Vol. 49, No. 2,
                                                                                               February 2001.
throughput is more in the case of MRWA when compared to
                                                                                        [7]    Jingyi He, S.H. Gary Chan and Danny H.K. Tsang, “Routing and
REMR.                                                                                          Wavelength Assignment for WDM Multicast Networks”, In the
   Figure.6 shows the end-to-end delay occurred when                                           proceedings of the IEEE GLOBECOM 2001.
varying the number of traffic sources. It shows that the delay                          [8]    Anping Wang, Qiwu Wu, Xianwei Zhou and Jianping Wang, “A New
                                                                                               Multicast Wavelength Assignment Algorithm in Wavelength-Converted
of MRWA is significantly less than the REMR.                                                   Optical Networks”, International Journal of Communications, Network
    Figure 7 shows the bandwidth utilization obtained when                                     and System Sciences, 2009
varying the number of traffic sources. MRWA shows better                                [9]    G. M. Fernandez and D. Larrabeiti, “Contributions for All-Optical
                                                                                               Multicast Routing in WDM Networks”, 16th International Congress of
utilization than the REMR scheme.                                                              Electrical Engineering, Electronics and Systems, IEEE INTERCON,
                                                                                               2009
    Name of                    Effects on varying            Effects         on
                                                                                        [10]   Nina Skorin-Kapov, “Multicast Routing and Wavelength Assignment in
  performance                  rate                          varying Traffic                   WDM networks: A Bin Packing Approach”, In the proceedings of optics
    metrices                   REMR      MRWA                REMR MRWA                         Infobase in the optical networks, 2006.
 THROUGHPUT                    0.49      0.71                1520      2000             [11]   Fen Zhou, Miklos Molnar and Bernard Cousin, “Multicast Routing and
 DELAY                         1440sec 1020sec               48.6sec 39.2sec                   Wavelength Assignment in WDM Mesh Networks with Sparse
                                                                                               Splitting”, The 5th International Workshop on Traffic Management and
 UTILISATION                   0.0325    0.041               0.456     0.7                     Traffic Engineering for the Future Internet, Dec- 2009.
                                                                                        [12]   Yuan Cao and Oliver Yu, “QoS-Guaranteed Routing and Wavelength
                                                                                               Assignment for Group Multicast in Optical WDM Networks”,
                                    VI. CONCLUSION                                             Conference on Optical Network Design and Modeling, 2005
    In this paper, a multicast routing and wavelength                                   [13]   N.Kaliammal and G. Gurusamy, “Resource Efficient Multicast Routing
assignment technique in WDM networks is developed. In this                                     Protocol for Dynamic Traffic in Optical WDM Networks”, European
                                                                                               Journal of Scientific Research, 2010
technique, the incoming traffic is sent from the multicast
                                                                                        [14]   Network Simulator: www.isi.edu/nsnam/ns
source to a set of intermediate junction nodes and then, from
the junction nodes to the final destinations. The traffic is



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                                                                                                                         ISSN 1947-5500
                                                                    (IJCSIS) International Journal of Computer Science and Information Security,
                                                                    Vol. 8, No. 7, October 2010



                   N. Kaliammal received the B.E (ECE)., M.E(Applied                   pursuing the Ph.D. degree in Optical Networking, under the guidance of
                   electronics), degrees from the Department of Electronics            Dr.G.Gurusamy, Dean and Head/ EEE Department, Bannariamman Institute
                   and Communication Engineering ,from Madurai Kamaraj                 of Technology, Sathyamangalam, Tamil Nadu.
                   University , Bharathiar University, Tamilnadu , in 1989,
                   1998, respectively. From 1990 to 1999, she served in the            Dr.G.Gurusamy, received his BE, ME and PhD degree from PGS college of
                   PSNA College of Engineering & Tech, Dindigul,                       technology-Coimbatore. He has 35 years of teaching experience in PSG
                   Tamilnadu, as Lecturer. From 1999 to 2009, she was in               College of technology-Coimbatore. He is currently working as a Prof &
                   RVS College of Engineering & Tech, Dindigul, Tamil                  Dean/in EEE Department of Bannariamman Institute of Technology-
Nadu, as assistant professor and Associate Professor. Currently she is working         Sathyamangalam.
as Professor in NPR College of Engineering &Technology She is currently




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                                                                                                                     ISSN 1947-5500

								
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