TCP (Transmission Control Protocol) is a connection-oriented, reliable, byte stream-based transport layer communication protocol that is used in client-to-server transport protocols for various enterprise applications popularly. As we all know, the TCP protocol establishes a connection through a "three-way handshake." This method of establishing a connection prevents the wrong connection from being generated.
The process of TCP three-way diagram
1) The client sends a SYN (SEQ=M) message to the server and enters the SYN_SEND state.
2) The server receives the SYN message, responds to a SYN (SEQ=N) ACK (ACK=M+1) message, and enters the SYN_RECV state.
3) The client receives the SYN packet from the server, responds with an ACK (ACK=N+1) message, and enters the Established state.
After the three-way handshake is completed, the TCP client and the server successfully establish a connection and start transmitting data.
As it shows in above diagram, a time of 2 RTTs is needed from client request to starting data transmission. For example, the server is in New York, USA, and the client is in Beijing. Assume that the client-to-server is connected by a dedicated line (MPLS), and the end-to-end latency is 230 ms. In this environment, the client needs 230 ms*2=460 ms from initiating the request to receiving data. The client-to-server data interaction (especially the web application) of most enterprise applications is a TCP short connection. In this scenario, the time used for TCP connection establishment is huge, and the application experience of the client is greatly affected.
To solve this problem, the TFO (TCP Fast Open) protocol was proposed in 2011, and an IETF draft was formed in February 2012, which was finally released as RFC 7413 in December 2014. Reference: https://en.wikipedia.org/wiki/TCP_Fast_Open
TCP Fast Open diagram
As it shows in above figure, TFO can accelerate the TCP handshake process and reduce the delay of application response from 2 RTT to 1 RTT. However, TFO requires to be deployed on both server and client to take effictive, this increase the complexity of enterprise application deployment, so most enterprise applications have not been developed based on this protocol.
AXESDN's TCP optimization suite deploys TFO as an optimization feature on the core network cloud. Enterprise users do not have to consider deploying TFO in their own applications, and they can have the application acceleration experience brought by TFO with AXESDN SD-WAN. Now, AXESDN's NaaS (Global Smart Networking) and ADAS (Global Application Acceleration) support TFO, and no software changes are required for clients and servers.
TFP deployment on AXESDN Cloud
NaaS (Global Smart Networking)
ADAS (Global Application Acceleration)
Test comparison (Akamai vs. AXESDN)
Test Application server: The source server (169.46.141.xx) is deployed in Dallas, USA, and the application protocol is http.
Test tool: Cloudwise (监控宝)
Test client: Liaoning Dalian Unicom, Henan Kaifeng Unicom, Jiangsu Changzhou Telecom, Shandong Jinan Unicom, Shaanxi Xi'an Telecom
Test results (take the average test result of all test client)
- Akamai (green) vs. AXESDN TFO off (purple), from overall statistic, the application response time is equivalent, but AXESDN is more stable than Akamai
- Akamai (green) vs. AXESDN TFO on (blue), obviously, the application response time is accelerated by AXESDN significantly, which is much more lower and stable than Akamai
After AXESDN turned on the TFO function, the application performance was significantly improved for user in China mainland to access the application deployed on the Dallas server.
- AXESDN TFO ON vs. OFF, application performance can be acclerated about 30%
- AXESDN TFO ON vs. akamain application performance can be acclerated 30% to 100%.
Please contact sales@axesdn. for a POC
