TCP performance in multi-hop wireless ad hoc networks: challenges and solution

Al-Jubari, Ammar Mohammed; Othman, Mohamed; Mohd Ali, Borhanuddin; Abdul Hamid, Nor Asilah Wati

doi:10.1186/1687-1499-2011-198

EURASIP Journal on Wireless Communications and Networking

Table 2 Comparison of the main characteristic of various TCP Enhancements

From: TCP performance in multi-hop wireless ad hoc networks: challenges and solution

	"TCP-Vegas"	"TCP-Westwood"	"TCP-CL"	"Channel Efficiency-Based Transmission Rate Control"	"TCPCC"
	[33]	[34]	[35]	[36]	[37]
DEALING WITH ROUTING FAILURES	No.	No.	No.	No.	No.
DEALING WITH WIRELESS ERRORS	No.	Yes: ssthresh and cwnd are assigned based on the estimated bandwidth.	Yes: It uses negative acknowledgment (NAK) to distinguish wireless loss from congestion loss and retransmit the corrupted packet.	Yes: it uses channel efficiency to notify TCP about the available bandwidth.	Yes: channel utilization (CU) is used to characterize the network status.
DEALING WITH CONTENTION	Partial: It maintains a stabler cwnd which may reduce contention at lower layer.	Partial: The growth of cwnd is carefully controlled based on the estimated bandwidth.	Yes: it extends the IEEE 802.11 DCF scheme to reduce the effects of link-layer contention,	Partial: comparing channel efficiency to TCP rate may reduce contention at lower layer.	Yes: contention ratio (CR) is used to characterize the contention status
DEALING WITH RETRANSMISSION	No.	No.	the retransmission is based on NAK reception	No.	No.
DEALING WITH TCP CONGESTION CONTROL MECHANISM	Yes: it reduces cwnd only by a quarter if the loss is detected by the new faster retransmission mechanism.	Yes: ssthresh and cwnd is calculated based on the estimated bandwidth.	Yes: It modifies the slow start and cwnd based on NAK and ACK reception	Yes: cwnd is assigned based channel efficiency.	Yes: cwnd is assigned based on channel utilization (CU) and contention ratio (CR).
DEALING WITH HIDDEN EXPOSED PROBLEM	No.	No.	No.	No.	No.
DEALING WITH TCP RATE	Yes: the rate is estimated based on the available bandwidth	Yes: the rate is estimated based on the available bandwidth.	Yes: TCP sender controls its transmission rate based on the feedback information.	Yes: TCP sender controls its transmission rate based on the feedback information of channel efficiency.	Yes: TCP sender controls its transmission rate based on the feedback information of the network status.
DEALING WITH TCP ACK	No.	No.	Yes: the NAK notification is sent in piggyback mode with the return TCP ACK segment.	No.	No.

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