Network Simulator - 2

Project Made by Min-Soo Kim and Kang-Yong Lee

Ajou University, Division of Information & Computer Engineering2003/06/09

Index1. Purpose & Necessity2. Sample Network Architecture3. Proposed Network Architecture4. How to Implement5. Advantages & Drawbacks6. Project Schedule7. Implementation 8. Core Source

Packet Link Layer Channel MAC Layer

9. Simulation Environment10. Simulation Video11. Simulation Result

1. Purpose & Necessity

We will modify the network architectures which are assumed by sample NS-2 code.

Existing Network Architecture in sample code Physically flat network architecture. All nodes and routers have channel with homogeneous capability (link).

Proposed scheme

In real world, there is non-homogeneous channel capacity (link). We consider routers and nodes which have group concept. and all routers can communicate with each other, directly

2. Existing Network Architecture

n#

R

: Node

: Router

: Network (Ethernet)

n1

n2

n3

n4

n5

R

R

n6

n7

R

3. Proposed Network Architecture

Group 1

Group 2

Group 3

: New Added Channel

n1

n2

n3

n4

n5

R

R

n6

n7

R

Group 4

4. How to Implement – Data structure

Node Information – Routing module

Group Membership Table

- Routing module maintains group membership table which contains nodes ID in the same physical group

Group Membership Table

- Routing module maintains group membership table which contains nodes ID in the same physical group

Additional define a new packet field

- channel mode (for channel layer)

in common header field

Additional define a new packet field

- channel mode (for channel layer)

in common header field

Packet header - packet

Routing Module

If destination node is not located in

same physical group with router ?

Set the group field valueto New channel mode

else

Set the group field valueTo Normal mode

If destination node is not located in

same physical group with router ?

Set the group field valueto New channel mode

else

Set the group field valueTo Normal mode

Channel

Inter group traffic or

Intra group traffic(Using channel

field)?

Inter group traffic or

Intra group traffic(Using channel

field)?

Existing schemeExisting scheme New Added Channel

- Delay control

New Added Channel

- Delay control

Receives packet to transmit from upper layer

4. How to Implement – Algorithm

5. Advantages & Drawbacks Advantages

Reducing the number of packets Guarantees good QoS

- High transmission speed (through New added-Channel)

- More reliable transmission (high delivery ratio)

Drawbacks

Additional overheads - Packet size is increasing (header field - channel field)- All routers must maintain the information of group

member- All routers must equip two link

Potential bottleneck problem at the router

6. Project Schedule

5 / 26 5 / 28 6 / 1 6 / 3 6 / 5 6 / 7

Specific Design

Packet structure analysis

Link, Channel analysis

5 / 24

Coding – Link, channel

Coding - routing

Coding - packet

Debugging & Simulation

Result Analysis

L : By Kang-Yong Lee

K : By Min-Soo Kim

L , K

K

L

L

K

L, K

L, K

L, K

7. Implementation – Original Concept

arpresolve(p);

기존 LAN 에서의 Packet forwarding one lanrouter object per a LAN For every node on the LAN, the LL has a pointer to the lanrouter

lanrouter_->next_hop (p) ?

next_hop(packet *p)

schedule (downtarget_, p, delay_)

recv(p)

Direction ->Down sendDown(p)

Direction ->Up sendUp(p)

sendUp(p)

LL::sendDown()

YES

NO

7. Implementation – Proposed Concept(1)

Before forwarding a packet, if “I am a router”, send the packet through “Direct Channel” to another router

arpresolve(p)

lanrouter_->next_hop (p)?

next_hop(packet *p)

schedule(downtarget_, p, delay_)

Direction ->Down sendDown(p)

YES

NO

Am I router ?

NO

Inter or Intra

Send the packetto other router throughDirect Channel

Send the packetto other router throughNormal Channel

YES

Inter

Intra

Modified part

LL::sendDown()

7. Implementation – Proposed Concept(2)

Channel part

Received packet

cmn_hdr->channel_type()NORMAL_CHANNEL

DIRECT_CHANNEL

Set the variables characterizing Direct Channel

Set the variables characterizing Normal Channel

Modified part

Channel::sendUp()

Am I router ?

MAC layer

7. Implementation – Proposed Concept(3)

NO

Received packet

cmn_hdr->channel_type()DIRECT_CHANNEL

packet::free(p)YES

NORMAL_CHANNEL

Modified part

Mac-802_3::recv()

8. Core Source – Packet

Add the new packet field : which_Channel_

New packet header field

8. Core Source – Link Layer

Distinguish the packet transmission type : Inter ? or Intra ?

Set the channel type to use

8. Core Source – Channel

Characterizing “Direct Channel” : delay

Set the delay of channel

Send packet

8. Core Source – mac layer

Packet Drop or Receive ?

If I am not a router, I must drop the packets which are received by Direct

Channel.Because I don’t have the Direct Channel

Link

9. Simulation Environment

Simulation Environment The number of Node : 12 nodes

The number of Group : 4 physical groups

Simulation Time : 5 sec

Packet Size data packet : 1000 bytes ack packet : 40 bytes

Simulation Scenario * source : node 0

TCP Reno Agent * destination : node 14 TCP Sink Agent

10. Simulation Video

Other Meterials

11. Simulation Result

Transmission Reliability

0.95

0.96

0.97

0.98

0.99

1

Proposed Scheme Original Scheme

Receiv

ed p

kt(

s)/

Tra

nsm

itte

d p

kt(

s)

Simulation Result Transmission Reliability (Received pkt / Transmitted packet) Original scheme : (1166/1181) = 0.9872 Proposed scheme : (1172/1184) = 0.9898

Transmission Time (End-to-End delay) Original scheme : 0.008 (sec) Proposed scheme : 0.005 (sec)

Transmission Time

0

1

2

3

4

5

6

7

8

9

10

Proposed Scheme Original Scheme

End

-to

-E

nd

Dela

y (m

s)