Method and apparatus for controlling handshake in a packet transmission network
The present invention relates to a method and apparatus for controlling a handshake operation. Datagram Transport Layer Security (DTLS) is an important secure protocol in the IP based Internet of things. The performance of DTLS handshake can be significantly affected by network status, traffic and packet loss rate, etc. It is therefore suggested evaluating a package loss rate and estimating causes of packet loss. Then, a DTLS handshake strategy may be changed adaptively based on the detection of packet loss and network status. As a result, the successful rate and delay of DTLS handshake can be improved. An acknowledgement and a non-acknowledgement mode may be used in a hybrid way to evaluate the package loss rate and estimate causes of packet loss and eventually improve performance of DTLS handshake.
1. An apparatus for controlling handshake in a packet transmission network, the apparatus comprising:
a processor to detect packet loss in a handshake-based packet transmission and for estimating a cause of the detected packet loss, and change a handshake strategy of the packet transmission based on the estimated causes,
wherein the processor estimates a packet loss rate caused by said estimated cause and to estimate a remaining time for handshake based on the packet loss rate, to compare the remaining time with a predetermined handshake timeout, changes the handshake strategy upon determination that the estimated remaining time is larger than the predetermined handshake timeout, estimates a wireless loss when the detected packet loss is distributed randomly or when delays between each received packet and respective subsequent packet of the received continuous packets are determined by the processor to be equal, and
wherein, when the processor has estimated a wireless loss, then the processor estimates a packet loss rate, estimates a remaining time for handshake based on the packet loss rate, to compare the remaining time with a predetermined handshake timeout, and increases a transmission rate of the packet transmission proportional to a ratio between the estimated remaining time for handshake and the predetermined handshake timeout if the estimated remaining time is larger than the predetermined handshake timeout.
2. The apparatus of claim 1 , wherein the processor detects the packet loss based on a sequence of received packets.
3. The apparatus of claim 2 , wherein the processor detects the packet loss based on a sequence of ClientHello messages of a DTLS handshake signaling.
4. The apparatus of claim 1 , wherein the detector processor estimates a congestion loss as the cause of the detected packet loss if a delay between received continuous packets varies or if there is a disorder between received continuous packets.
5. The apparatus of claim 4 , wherein, if the processor has estimated a congestion loss, then the processor estimates a packet loss rate, estimate a remaining time for handshake based on the packet loss rate, to compare the remaining time with a predetermined handshake timeout, and to increase a transmission interval and decrease a transmission rate of the packet transmission if the estimated remaining time is larger than the predetermined handshake timeout.
6. The apparatus of claim 1 , wherein, when the processor has estimated a congestion loss and when the apparatus is located on a server side of the packet transmission, then the processor notifies a client side of the packet transmission to prolong the handshake timeout.
7. The apparatus of claim 1 , wherein the processor estimates the packet loss rate by calculating a total transmission time until receiving the last acknowledgement of a predetermined handshake message and using the equation
P
L
=
1
-
2
N
s
,
wherein N S denotes the calculated total transmission time and P L denotes the estimated packet loss rate.
8. The apparatus of claim 6 , wherein said predetermined handshake message is a ClientHello message of a DTLS handshake signaling.
9. A method of controlling handshake in a packet transmission network, the method performed by a processor comprising:
detecting packet loss in a handshake-based packet transmission;
estimating causes of the detected packet loss;
estimating a packet loss rate caused by said estimated cause;
estimating a remaining time for handshake based on the packet loss rate;
comparing the remaining time with a predetermined handshake timeout; and
if the estimated remaining time is larger than the predetermined handshake timeout, changing a handshake strategy of the packet transmission based on the estimated causes, and estimating a wireless loss if the detected packet loss is distributed randomly or if delays between each received packet and respective subsequent packet of the received continuous packets are determined by the processor to be equal, and when estimated, by the processor that, a wireless loss exists, estimating a packet loss rate, estimating a remaining time for handshake based on the packet loss rate, to compare the remaining time with a predetermined handshake timeout, and increasing a transmission rate of the packet transmission proportional to a ratio between the estimated remaining time for handshake and the predetermined handshake timeout if the estimated remaining time is larger than the predetermined handshake timeout.
10. A computer program product comprising a plurality of program code portions, stored in a non-transitory computer readable medium, for carrying out the method of claim 9 when run on a computer device.
11. The method according to claim 9 , further comprising the following step:
if the estimated remaining time is smaller than the predetermined handshake timeout, then do not change a handshake strategy of the packet transmission based on the estimated causes.
12. The apparatus of claim 1 , wherein the processor does not change the handshake strategy upon determination that the estimated remaining time is smaller than the predetermined handshake timeout.
13. The apparatus of claim 5 , wherein the processor estimates the packet loss rate by calculating a total transmission time until receiving the last acknowledgement of a predetermined handshake message and using the equation
P
L
=
1
-
2
N
s
,
wherein N S denotes the calculated total transmission time and P L denotes the estimated packet loss rate.