Starvation in Wireless Multihop Networks A Solution

We repeat the experiment with a flow
in the middle scenario but this time
using DiffQ TCP. DiffQ TCP is the new
congestion control algorithm that we
have developed.

DiffQ is a generic congestion control
framework which is based on differential backlog based backpressure. Differential Backlog
based backpressure was proposed in
the context of utility maximization by
Tassiulas and Ephremides. DiffQ TCP is the direct application of these
concepts in practice.

DiffQ TCP relies on source rate
control, flow scheduling and MAC
prioritisation. Source rate control is
done using backpressure. The flow
scheduling at each node selects the
flow with the maximum queue differential and schedules it for
transmission. MAC priority is assigned
based on the differential backlog.

In this scenario, the flow sn2e19 - sn2e10 gets lesser access to the
medium as before. This results in
a queue build up at intermediate nodes. While TFRC suffered starvation
because of queue build up, DiffQ TCP flushes the queues quickly due to flow
scheduling and MAC rioritisation. MAC
prioitisation ensures that the flow
which is suffering unfairness gets preferential access to the medium.

We do not observe queue overflows with
DiffQ TCP which points to the effectiveness of the differential
backlog scheme in practice.

Category:

Science & Technology

Tags:

• Congestion
• Control
• Wireless
• Multihop
• Networks
• NCSU
• Networking
• Differential
• Backlog
• Backpressure