Cao et al. EURASIP Journal on Wireless Communications and Networking
(2016) 2016:229
Page 3 of 13
loss may result in numerous O
3
packets buffered in the
space-limited receiver buffer and cause a severe hand over
delay problem. Worse still for the time-sensitive multime-
dia streaming services, the delayed delivery of multime-
dia packets may lead to some of these received packets
becoming unplayable.
In order to address above concerns, this paper extends
our previous work SCTP-Rev [26] to propose a receiver-
assisted cellular/WiFi handover management mechanism
(dubbed as SCTP-Rev
+
) for SCTP-based heterogeneous
multimedia delivery. SCTP-Rev
+
moves some operations
including path sending rate estimation and primary path
selection from the sender onto receiver in order to achieve
load-balancing between the sender and receiver. More-
over, SCTP-Rev
+
includes a simple retransmission-aware
model that makes it possible to handle data loss and trig-
ger proper fast retransmission. The major contributions
of the paper are introduced as follows:
•
It moves the path sending rate control and primary
path selection operations from the sender onto the
receiver side in order to possibly help SCTP alleviate
the workload of the sender.
•
It develops a receiver-triggered path fast recovery
strategy in order to prevent bursty packet injection
while maximizing resource utilization when a
primary path switching event occurs.
•
It includes an efficient loss detection/recovery
mechanism in order to make a SCTP sender possibly
identify a packet loss event timely and improve the
performance of multimedia transmission.
The remainder of this paper is organized as follows.
Section 2 introduces the detail design of the proposed
SCTP-Rev
+
solution. Section 3 presents the perfor-
mance evaluation and analysis of the SCTP-Rev
+
solution.
Section 4 concludes the paper and gives some interesting
directions for future work.
2 SCTP-Rev
+
detail design
In current SCTP handover solutions, the sender needs to
monitor per-path’s transmission quality and make a han-
dover decision. In contrast, the SCTP-Rev
+
sender does
not need to detect the transmission quality for each path,
it just uses per-path’s sending rate, which is calculated
and advertised by the receiver, as the transmission qual-
ity metric to make a handover decision. Such way possibly
helps the SCTP-Rev
+
to reduce the sender’s computing
overhead and achieve a desired load-sharing between the
sender and receiver.
Figure 2 shows the architecture of SCTP-Rev
+
system.
SCTP-Rev
+
mainly consists of a receiver-based sending
rate estimator (SRE-rev), a receiver-assisted path handover
trigger (PST-rev), and a retransmission-aware fast retrans-
mit (RAF-rtx) module. The major functions of the three
components are described as follows:
•
SRE-
rev
is devoted to calculating per-path’s sending
rate at SCTP receiver side and giving the sender
feedback on the paths’ sending rate value.
•
PST-
rev
is devoted to choosing a proper primary
path at SCTP receiver and giving the sender feedback
on the selected primary path information for
handover decision.
•
RAF-
rtx
is devoted to helping the SCTP sender
possibly detect packet loss timely and trigger fast
retransmission for loss recovery.
Like TEAR [24], a well-known receiver-driven TCP-
based flow control solution, SCTP-Rev
+
runs seven states
at receiver side for flow control, which are Slow Start,
Congestion Avoidance, Slow Start Ready, Timeout, Con-
gestion Avoidance Ready, and Fast Recovery. The state
transition among the seven states has been detailed in
the TEAR solution. Meanwhile, the SCTP-Rev
+
uses the
round information, which is already defined in the TEAR
solution, to measure the values of round-trip time (RTT)
...
Application
Layer
SCTP-based Transport Layer
Sender buffer
Receiver-assisted
Path Handover Trigger
...
Stream
n
Stream 1
Unbound
and collect
data chunks
Path n
Path 1
S
t
r
e
am
1
S
t
r
e
a
m
n
Data
Scheduler
Appropriate sending rate (ASR) advertising
Primary path selection and advertising
S
P
C
PR
State transition
Receive Buffer
...
Router
SCTP Receive
SCTP Sender
Internet
...
Retransmission-aware
Fast Retransmit module
Receiver-based
Sending Rate Estimator
Data
Stream
SLOW-START PATH-SELECTION
CONGESTION-
AVOIDANCE
PATH-FAST-
RECOVERY
S P
C
PR
Fig. 2 SCTP-Rev
+
architecture