My name is Torsten Lachmann. I look after all things technical and would like to explain how eBooks are delivered in LearningField and how we ensure that our service is fast and reliable.
When a teacher or school administrator uses LearningField for the first time they probably go to our website where they can select the content they want to read or want their students to read. Content can be selected on a chapter basis by adding it to the personal library or to a library of a group. Once a chapter is in a library it can be downloaded with one of the LearningField eReader apps for Windows, Mac, Android or iPad. On the eReader app a user can login with the same username and password used on the website which allows them to download and read the encrypted chapter files.
We have worked hard to provide the best process for delivering texts to students. We ensure that a chapter added to a group is automatically available to all students in that group, immediately, on all their devices. They don’t need to go to a separate site to retrieve their texts, it’s all there behind the same login, with a consistent experience. Students directly login to the eReader app and download the chapter and then it’s available offline or online, which is also important to many students and schools.
All encrypted chapters are the same for all users but each user has an individual key to open the file inside the app. This allows us to do a few things to reduce our server load and thereby ensure that LearningField is always available and responsive even if thousands of teachers and students use it simultaneously.
Our hosting is just being moved to Sydney with a strong link to all regions in Australia. We will also have copies of all chapters available in a so called CDN or content delivery network in multiple locations around the country. With local hosting, CDN and chapter size downloads (rather than the entire books) we are doing our best to minimise download times for teachers and students.
Given that all encrypted chapter files are the same for all users, a school can actually cache those files inside their network in order to reduce the download times even further. This also reduces the strain on their internet connection. The way it works is that the first user who downloads a chapter receives the file from our server and it will be placed in the school’s cache at the same time. Any further downloads from other users will be received directly from the caching server inside the school network. So for a given class chapter, 1 person might download it from LearningField but 25 others retrieve it from within the school network. This can bring chapter download times down to a few seconds.
A school’s internet connection is typically very strong and I have seen maximum speeds of 1 GB/s which is about 40 times faster than a typical personal ADSL2+ connection. While this sounds very fast on first look when you divide it by a whole school, with say 2000 students, it only leaves 500KB/s per student which will feel quite slow to a student who is used to their own fast speeds at home. Most schools have fewer students but then also often a connection that is not as fast.
We have successfully implemented two caching solutions with Netbox Blue and Squid. We are working on other caching products too so that we can enable local caching in as many schools as possible. We found that this can reduce download times to a few seconds per chapter even when a whole class downloads the same chapter simultaneously which ensures a great user experience.