PRESENTED BY-: SUBMITTED TO-: RAJKUMAR JAIN DR. SANJIV SHARMA

The objectives of a transport layer protocol include setting up of:End-to-end connectionEnd-to-end delivery of data packetsFlow controlCongestion control

Transport layer protocolsUser datagram protocol (UDP): unreliable and

connection-less transport layer protocols

Transmission control protocol (TCP): reliable, byte-stream-based, and connection-oriented transport layer protocols

These traditional wired transport layer protocols are not suitable for ad hoc wireless networks.

Induced traffic refers to the traffic at any given link due to the relay traffic through neighboring links.

Induced throughput unfairness refers to the throughput unfairness at the transport layer due to the throughput/delay unfairness existing at the lower layers such as the network and MAC layers.

Separation of congestion control, reliability, and flow control could improve the performance of the transport layer.

Power and bandwidth constraints affects the performance of a transport layer protocol

5

Transport Layer Solutions for Ad Hoc Wireless Networks

Split Approach

Other transport layer approach

End-to-endapproach

Split-TCP

ACTP

ATP

TCP-ELFN

TCP-F

TCP-Bus

ATCP

TCP over ad hoc wireless networks

Frequent path breaks Effect of path length Network partitioning and remerging Misinterpretation of packet loss-:1.collisions due to hidden terminal problem.2. interference: wired links are well isolated,

wireless links interfere.3.frequent path breaks, mobility.

TCP with explicit link failure notification (TCP-ELFN)Handle explicit link failure notificationUse TCP probe packets for detecting the route

reestablishment. either sending an ICMP destination

unreachable message (DUR). Inserting info regarding link break in Route

Error message of the routing protocol.

Once the TCP-ELFN sender receives the ELFN packet-:

It disables its retransmission timer and CW.

Enters a standby state.Being in standby state the TCP-ELFN

sender-: periodically originates probe packets to

see if a new route is established. when ACK for a probe packet is received

TCP-ELFN continues to perform as usual.

ADVANTAGES-: Less dependent on the routing protocol and requires only

link failure notification.

DISADVANTAGE-: The congestion window after a new route is obtained may

not reflect the achievable transmission rate acceptable to the network and TCP receiver.

THANK YOU