h*h: hop by hop analysis of tcp-ia for multi-hop wireless networks - … · fig1.flowchart . source...

H*H: Hop by Hop Analysis of TCP-IA for Multi-Hop

Wireless Networks

Vani Chawla

PhD Scholar, Department of Electronics and Communication, AFSET,

Faridabad (India)

Email:[email protected]

Abstract The main problem of TCP in multi-hop

wireless networks is the huge number

of medium accesses done by TCP.

Further, increased transmission of the

acknowledgment packets results in the

collision, hence cause the degradation

of performance of TCP, Congestive

network, channel losses, bandwidth

limitations degrades the TCP

performance. To overcome these

drawbacks, in this paper, comparison

has been done between TCP-IA and

TCP reno in terms of various metrics

by varying number of hops from 2 to

10 in a time interval of 25 seconds.

Results show that TCP-IA has better performance.

Keywords— TCP-IA, MHF, ACK, Hops

I. INTRODUCTION The network of computers and devices that are associated with wireless

communication links are termed as multi-

hop wireless networks. In most cases, the

links are employed with the help of digital

packet radios. [1]

Universally, the applications of wireless

networks are well-liked in the corporate

world and residences. The need for the

people to communicate anytime,

anywhere with the communication

devices has made look for innovative

technologies. At last, the main function

in the future communication systems

are predicted to be performed by wireless communications. The flexible

organization of the mobility patterns,

cheap deployment, easy maintenance

and improved performance makes

wireless networks more advantageous.

In wireless multihop ad hoc networks,

multiple wireless hops are utilized to

link two distant nodes. Here the nodes

interact to each other directly and must

be able to communicate in a self-

regulating manner. The application of

this networks enabling communication

across several wireless hops results in

significant property for communication

that is more susceptible to changes in

the topology and channel fading. [2]

Daniel Scofield et al [11] designed

HxH, a hop-by-hop transport protocol that uses credit-based congestion

control and reverse ACKs to solve the

Vani Chawla, Int.J.Computer Technology & Applications,Vol 5 (3),1276-1281

IJCTA | May-June 2014 Available [email protected]

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ISSN:2229-6093

mailto:[email protected]

problem with TCP. The problems include

contention, interference, the hidden and

exposed terminal problems, shared

queues, half-duplex links, and route

changes due to mobility. Credit-based

congestion control reacts quickly

whenever network conditions change, and

can improve fairness among flows

competing on the same path. The drawback of the proposed approach is

that, congestion control algorithms that

use rate-based and pricing based feedback

is not used.

Yao-Nan Lien et al [13] proposed the

Hop-by- Hop TCP protocol for sensor

networks aiming to accelerate reliable

packet delivery. Hop-by-Hop TCP makes

every intermediate node in the

transmission path execute a light-weight

local TCP to guarantee the transmission of

each packet on each link. It takes less time

in average to deliver a packet in an error-

prone environment. In the future, they will

use One-Hop TCP to serve all TCP and

even UDP so that the number of packets

transmitted on the air can be greatly reduced.

In section II,TCP-IA ALGORITHM is

discussed with the help of flowchart and

an example.In section III, SIMULATION

topology and section IV,RESULTS are

shown ,where comparison hs been done

between TCP-IA and TCP in various

metrics by varying number of hops.Based

on simulation results ,in section V,

CONCLUSION is concluded and at last

ACKNOWLEDGMENTS and

REFERENCES are mentioned.

II. TCP-IA ALGORITHM

Yes

No

Yes

No

Fig1.Flowchart

Source S sends TCP Dp to receiver R

Link layer of S calculates bandwidth and delay, and adds it to MHF

Transmit the packet to next node

While k

Packets reach R

Next node estimates bandwidth and delay, adds it to MHF and send it

At R, D performs delay management

If packets are out-of-order or have

max delay a delay and

min. bandwidth

Reduce D

and send ACK

to S

R sends single ACK to S that denotes

the successful transmission

S adjusts congestion window based on bandwidth And

delay of the path

End



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In our algorithm, following assumptions

are made.

Let S and R be the sender and receiver,

respectively. Let Dp be the data packets transmitted. Depending on the received data, R sets the

timer which will be reset that can cause

delayed acknowledgement (ACK).

Let R has the delaying window of size D. Let S has the congestion window of size

W.

Initially R is set to the value of k packets.

(The value of k can be set at runtime,

depending on the experimental

setup)algorithm is explained with the help

of flowchart ans an example.

S L1 L2 Ln R

TCPDp ACK

I1,I2,I3...In represents the nodes

L1,L2.....Ln represnets the links

MHFU represnts MAC header filed

updation.

Fig 2 Intelligent Acknowledgement

Approach Fig2 describes the intelligent

acknowledgement technique in a multi-

hop wireless networks. S initiates the

transmission by sending the TCP Dp to R.

On the reception of Dp, L1 computes the

bandwidth and delay. The computed

values are updated in the MHF. I2 after the

reception of the data packet from I1

performs the same measurements for

link L2. Then, it takes the minimal

value for the measured bandwidth of

links L1 and L2. Delay experienced by

Dp on the link L2 is summed with the

delay on the link L1. The computed

bandwidth and delay are updated in

MHF. The process is continued till k Dp

reaches R. After k Dp reaches R, it replies back S with the single ACK. The proposed approach is more

efficient and advantageous due to the

following reasons

It avoids the degradation of

transport layer protocol due to

congestion in the network

layer.

The performance is further

enhanced since bandwidth and

delay information is gathered

in the link layer.

Since the transmission of ACK

packets are reduced, the

collision of data and ACK is

minimized.

III.SIMULATION

We use NS2 [20] to simulate the

improved TCP with intelligent

acknowledgement (TCP-IA) protocol.

In our simulation, the channel capacity

of mobile hosts is set to value: 2 Mbps.

We use the IEEE 802.11 for wireless

LANs as the MAC layer protocol. In our simulation, 11 mobile nodes are

arranged as a line topology in a 1500

meter x 1500 meter region as shown in

Figure 3. All nodes have the same

transmission range of 250 meters

I1

I3

In

I2



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Fig 3. Simulation Topology

IV.RESULTS

We compare TCP –IA with simple TCP

New Reno protocol. The performance is

evaluated based on the following metrics:

Packet Delivery Ratio, Average end-to-

end delay, Drop, Throughput,

Bandwidth. We measure the above metrics

by varying the number of hops from 2 to

10 and for a time interval of 25 seconds.

Fig 4: Hopes Vs Delay

Fig 5: Hopes Vs Delivery Ratio

Fig 6: Hopes Vs Drop

Fig 7: Hopes Vs Received Packet

2 4 6 8 10

0

0.2

0.4

0.6

0.8

1

1.2

Hops

De

liv

ery

Ra

tio

Hops Vs Delivery Ratio

TCP-IA

TCP

2 4 6 8 10

0

50

100

150

200

250

Hops

Dro

p

Hops Vs Drop

TCP-IA

TCP

2 4 6 8 10

0

500

1000

1500

2000

2500

3000

3500

Hops

Pa

ck

ets

Hops Vs Packets Received

TCP-IA

TCP

2 4 6 8 10

0

0.5

1

1.5

2

2.5

3

3.5

Hops

Dela

y(s

ec)

Hops Vs Delay

TCP-IA

TCP



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Fig 8: Hopes Vs. Bandwidth

When the number of hops is increased, the

delay will be more which is depicted from

Figure 4. we can see that the end-to-end

delay of our proposed TCP-IA is less than

the existing TCP protocol, since the

number of acknowledgment packets are

reduced in the case of TCP-IA.

From figure 5, we can see that the

delivery ratio of our proposed TCP-IA is

higher than the existing TCP protocol,

since packet drop is reduced in TCP-IA.

The packet drop will be increased, if we

increase the number of hops. Hence the

received bandwidth, packets and packet

delivery ratio will be decreased. Figure 6,

shows the packet drop of both TCP and

TCP-IA. Since the congestion window is

adaptively adjusted, the packet drop is less for TCP-IA, when compared to TCP.

Because the bandwidth and delay are

measured from the link layer, the number

of packets received and bandwidth

received are higher for TCP-IA when

compared to TCP, as we can see from

figures 7 and 8, respectively.

V.CONCLUSION In this paper, we have analysed the

performance of TCP-IA an intelligent

acknowledgment technique in multi-

hop wireless networks by varying the

number of hops .The various

parameters used were Packet Delivery

Ratio, Average end-to-end delay, Drop,

Throughput, Bandwidth .The proposed

technique avoids the degradation of

transport layer protocol due to

congestion in the network layer. The

performance is further improved since

bandwidth and delay information is

gathered in the link layer. Since the transmission of ACK packets are

reduced, the collision of data and ACK

can be minimized. By simulation

results, we have shown that the

proposed technique improves the TCP

performance.

ACKNOWLEDGEMENTS

I would like to thank Professor Arti

Noor at CDAC Noida, for contributing

the idea of Hop by hop Analysis of

TCP-IA for Multi-Hop Wireless

Networks. Without her kind support

and assistance this work would not be

possible.

REFERENCES

[1]. Douglas S. J. De Couto,” High-

Throughput Routing for Multi-Hop Wireless

Networks”, Doctoral Dissertation, 2004 . [2]. T. Braun et al, “Addressing the

Challenges for TCP over Multihop Wireless

Networks”, 2005.

[3]. K. Nahm, A. Helmy, and C. J. Kuo,

2 4 6 8 10

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Hops

Ba

nd

wid

th

Hops Vs Bandwidth

TCP-IA

TCP



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“TCP over multihop 802.11 networks: Issues

and performance enhancement”, ACM, May 2005.

[4]. Myungjin Lee, Moonsoo Kang,

Myungchul Kim, and Jeonghoon Mo, “A

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Computer Communications, vol. 31, no. 11,

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[5]. Foez ahmed, Sateesh Kumar Pradhan, Nayeema Islam, and Sumon Kumar Debnath3,

“Performance Evaluation of TCP over Mobile

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[6]. Kanwalvir Singh Dhindsa Parminder

Singh Gurpal Singh, “Performance Study of

TULIP Protocol over 802.11 Wireless Networks”, International Journal of Computer

Applications, Volume 12– No.9, January 2011.

[7]. Hongqiang Zhai, Xiang Chen, and

Yuguang Fang, “Improving Transport Layer Performance in Multihop Ad Hoc Networks by

Exploiting MAC Layer Information”, IEEE

Transactions on Wireless Communications,

Vol. 6, No. 5, MAY 2007. [8]. Dzmitry Kliazovich, Fabrizio Granelli,

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wireless networks, ELSEVIER, Ad Hoc

Networks 4 (2006) 687–708. [9].Biaz S. and Vaidya N (1997) Technical

Report for TCP over Wireless Networks using

Multiple Acknowledgements, Texas A&M

University. [10]. Zhenghua Fuxiaoqiao Meng, Songwu Lu,

Lixia Zhang, Mario Gerla (2005) „The Impact

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performance‟, IEEE 2005, pp.1300-15. [11]. Daniel Scofield, Lei Wang, Daniel

Zappala: “HxH: a hop-by-hop transport

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WICON 2008: 16. [12]. H.Khalife, S.Mahfoudh and N.Malouch,

“A Hop-by-hop Node Failure Control Protocol

for Wireless Ad Hoc Networks: Towards MAC

layer Control”, In the proceedings

of the IEEE pimrc conference, September

2007 Athens, Greece. [13].17. Yao-Nan Lien, “Hop-by-Hop TCP

for Sensor Networks”, International Journal

of Computer Networks & Communications

(IJCNC), Vol.1, No.1, April 2009.



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