Big Data

48 

Big Data: Storage, Sharing, and Security

possible by keeping its inter-packet interval to as small as possible with maximum window size

of 16 mss. Instead of using AIMD, UDT uses AIMD with decreasing increases (DAIMD) [56],

which updates its congestion window as

cw

new

= w +



1

mss

if B ≤ C

max(10

(ceil(log

10

((B −C )∗mss∗8))

×

0.0000015

mss

,1/mss) if B > C

(3.1)

where:

B is estimated link capacity

C is current throughput

Once a NAK is received, UDT uses DAIMD to maximize sending rate by increasing window

size slowly when the sending rate is close to the available bandwidth measured at the start.

UDT changes its packet sending period at fixed intervals (10 ms ...