How to combat Latency during File Transfer
Recently we seem to be getting quite a few enquiries from companies experiencing difficulties with high latency during the file transfer process. It appears to be a wide spread issue, affecting businesses in a climate where everybody needs to get ahead of the game. Companies want – no need – their files right here, right now!!!
For those of us unfamiliar with the term, latency is an expression for the period of time taken to send a data packet from a source to the intended destination. The higher the latency, the slower the data transmission. This incorporates all elements involved in the file sending process – including encoding, transmission, and decoding.
There are certain delivery protocols (such as FTP) that are particularly susceptible to latency. This is because when sending packets of data to a remote site, the sending site waits for an acknowledgment that the packet has been received before sending the next one. This makes the problem extremely time consuming in the event of high latency. In extreme cases of latency, the time that it takes for the delivery of data and then the reply, can result in the data throughput levels dropping to a significantly low level, rendering the solution useless.
So, what can we do about it? There are several ways to combat this problem – one being to utilise a multi-threaded TCP protocol – working in the same manner as above ONLY multiple packet transfer requests are made at any one time, increasing the throughput. Another increasingly popular route is to adopt a UDP based delivery protocol, which applies a send and forget mentality i.e. they don’t wait for the acknowledgment receipt. This can significantly speed up the delivery process BUT then you have to consider the fact that other features are required, and UDP out of the box won’t work for everyone.
How can you measure the latency on your connection? Network tools like ping tests and traceroute measure latency by determining the time it takes a given network packet to travel from source to destination and back, the so-called round-trip time. Round-trip time is not the only way to specify latency, but it is the most common.
To test the latency on your Internet connection between 100’s of test servers you can use a tool like Speedtest.net, where you can test your bandwidth and latency against a local (London) server and say one in Bangkok.
On DSL or cable Internet connections, latencies of less than 100 milliseconds (ms) are typical and less than 25 ms desired. Satellite Internet connections, on the other hand, average 500 ms or higher latency.
So if you suffer from latency problems when it comes to file transfer, please feel free to contact Pro2col to discuss. Alternatively, you could have a look at the fast file transfer section on our website that details some solutions that may help.
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