Overlay Network Backup Bandwidth

1
Overlay Network? ??? Backup Bandwidth? ??

• ??????
• 19991260
• ???

2
Approach and Goal

• Find Overlay Network Model For Bandwidth
  Maintenance
• Find Overlay Network Model For Specific QoS
  Parameters

Simulation
Get the Best Overlay Network Model!!!
3
Overlay For Bandwidth

• Bandwidth is the basis for service.
• The smallest bandwidth between the hops.
• Persistent on several application.
• Ex Many P2P Application(Pruna, Soribada)

4
Bandwidth And QOS

• Human detect 150msec delay.
• Minimize primarily the network latency.
• The tolerance of audio degradation is less than
  that of video degradation.
• QOS for audio is harder.
• To keep the QOS, minimize the packet loss.

5
Overlay For QOS of VoIP

• Overlay

• UDP

• Localize the packet recovery within overlay
  hops-Network loss rate of 5 by recovery
  protocol.
• Recover the link failures by another pass.
• Routing algorithm than optimizes the probability
  being delivered within he delay.

• UDP exposes VoIP packets to network loss and
  failures.
• UDP is hard to recover the link failures.
• Not easy to optimize the routing algorithm.

6
Consideration

• QOS Routing Node for Contact Center
• Get the explicit path which have the highest
  bandwidth or the smallest traffic.
• Via Dynamic Routing between WAN and Overlay.
• Recover the packet loss.
• Contact center require the highest quality of
  VoIP.
• Do not consider the cost.
• Already pay the WAN and Overlay is backup.
• Service for customer is more important than cost.
• Always get the updated routing table.
• Reveal the current network situation.

7
Design
NODE
Routing Algorithm
QOS Routing Node

• Table For Path
• To 16 hops
• The largest bandwidth and the smallest hops

• Retransmission Manager
• Recover the packet
• Check the link state
• Check the traffic between the hops

• Link State List
• Interval Update
• All neighbor id
• Bandwidth, cost

8
QOS Routing Algorithm

• Assumption
• Link State List is always available.
• Link information is up-to-dated.
• Function
• Store all of the paths within 16 hops.
• Store the minimum value between hops along the
  way.
• Consider the minimum bandwidth instead of cost.
• Return the path which has the largest bandwidth
  although the count of hops is more.
• For efficiency, get the path from the path table.
• Use the Bellman-Form Algorithm.
• Each node tells its neighbors its distance (cost)
  to all other nodes.

9
Working
dest 0, hops 0 bw INF, prev 0 dest 1,
hops 1 bw 5.00, prev 0 dest 1, hops 2
bw 9.00, prev 2 dest 2, hops 1 bw
10.00, prev 0 dest 3, hops 2 bw 5.00,
prev 1 dest 3, hops 3 bw 8.00, prev
1 dest 4, hops 2 bw 7.00, prev 2 dest
4, hops 4 bw 8.00, prev 3
Cost 70 BW 8
2
4
Cost 100 BW 5
Cost 80 BW 9
Cost 50 BW 9
1
Cost 90 BW 9
3
5
Cost 60 BW 7
10
QOS Routing Algorithm(cont)

• Pseudo Code
• Let N Number of nodes
• C(i,j) Bandwidth of link (i,j)
• H(i,j) Next hop to get from node i to node j
• Algorithm at Node i
• Initialization (for all j)
• C(i,j) 0, if ji
• Inf, otherwise
• H(i,j) -1
• For some neighbor n Recv C(n,)
• Compute for each j
• C'(i,j) C(i,n) C(n,j)
• C(i,j) MinC(i,j), C'(i,j), if H(i,j) ! n
• C'(i,j), if H(i,j) n
• H(i,j) n if C'(i,j) lt C(i,j)
• Repeat recv-compute steps

11
QOS Routing Algorithm(cont)

• Pseudo Code For Compute the Road
• Algorithm From Node i to j over bandwidth
• Get the road table.
• Set minbw 0
• For each road to j
• check the bandwidth
• if the bandwidth is bigger than demand
• then
• accept the road and set minbw.
• Repeat compute steps by minbw until no road is
  found
• Return the road

12
Plan

• Simualation by NS.
• NS is simulation tool to implement virtual
  environment where we can use the real protocol.
• www.isi.edu/nsnam
• Develop Retransmission manager.
• Design and Develop the interface with NS.

13
Schedule

• 2005.3.102005.3.20. IP Product??? ?? ?? ? ???
  ??
• IP Product ??? ?? ??
• Case Study ????, ????, ??????, ?????? ASP
• 2005.3.212005.3.31. Solution ??
• 2005.4.1.2005. 4.15. Overlay Network ??? ??
• 2005.4.152005.5.10. Overlay Network Model
  Research
• Check that several Overlay algorithm consider QOS
  and Bandwidth.
• 2005.5.11.2005.5.18. Find the fittest QOS
  Routing Model for Solution
• Design the customized QOS Routing algorithm for
  contact center.
• 2005.5.21.2005.6.10. Design and Implement the
  Routing algorithm.
• Implement the simple MFC Program to check the
  work.
• 2005.72005.8 Study NS code.
• 2005.9 Develop the retransmission manager.
• 2005.10 Develop the interface with NS
• 2005.11 Simulation ? Performance ??
• 2005.12 Performance ?? ? Solution ??? ??