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Multi-constrained defragmentation algorithm (MCDFA) |
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Step 1: initialize the network status |
Step 2: initialize the network parameter N(V, L) |
V is the number of nodes, and L is the number of links between the nodes |
Step 3: each arrivals R(s,d,D,Gb) |
s-Source, d-Destination, D-Demand, and Gb-Gurd bands |
Step 4: find all possible routes(ki) |
Construct routing table Rt with respective modulation format and number of FSs using Equation (2) |
Step 5: for each kido |
Find the best RSA constraint (N, D) for from Equation (5) for spectrum allocation |
if the exact route is found from Equation (7) then |
Choose the channel from Equation (6) for RSA ← route + spectrum allocation policy |
Allocate Ri to the network |
else |
Reallocate neighboring connections of N, |
Find the best RSA constraint (N, D) for from Equation (5) for spectrum allocation |
if an exact route from Equation (7) is found then |
Choose the channel from Equation (6) for RSA ← route + spectrum allocation policy |
Allocate Ri to the network |
else |
if FSs cannot assign && > FItthen |
goto step 6: |
else |
Block the connection request Ri |
end if |
end if |
Step 6: Rc: set of connections that may be a necessity for reconfiguration |
Rl: connection leaving |
Pr(x): present route, Nr(x): next route |
if RcReconfigure Then |
for each link Rc Pr(x) then |
Rc ← Connection path share with some link Rl (which is occupied high FSs) |
While Rc ≠ Ø do |
Ri occupied the lowest FSs in Rc |
if Ri(shifted upper to lower optical path then |
Rc shares FSs with Ri (which is Occupied High FSs) |
end if |
Rc ← Rc\{Ri(} |
end while |
end for |
else |
for each link Ri Pr(x) and Rc Pr(x) then |
if new available FSs ≥ minimum required FSs for (Nr(x)) then |
Reassign route Pr(x) to Nr(x) |
end if |
end for |
end if |
Step 7: restart network parameters |
Step 8: end loop |
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