Saturday 29 November 2014

A Whole School Down the Wire

Another common objection raised to the adoption of SaaS technologies is the opinion that a single broadband connection is insufficient to support an entire school and that the quality of service will degrade as the number of students accessing external services increases.

Under normal circumstances it can be difficult to see how a school of 500 students might operate over a single broadband connection especially when networks appear to be slow and overloaded running across 1Gbs switches. Without closer examination it does seem counter intuitive to believe that placing all the services on the end of a slower connection could actually result in a more responsive system.

In support of this case, and to allow the bandwidth demands to be estimated with some degree of accuracy it's assumed that school will use Google G Suite for Education (GSfE) and the the primary file format is Google Docs.

Evidence suggests allowing 150Kbs for each GSfE editing session.  Using these figures it is conceivable that a significant number of users could be accommodated on a broadband connection.

Collecting information from a number of schools backs up this assumption. One example is from school that supports 800 students and 70 teachers on a full 1:1 Chromebook program with heavy GSfE usage. They record 40% bandwidth usage on average peaking to 70% 2-3 times a week on a 100Mbs circuit.

In fact schools report that the major factor affecting the user experience is not the number of active GSfE sessions but bandwidth being utilised by multimedia and data download streams during peak times. In a SAS/GSfE school this traffic needs to be closely managed because it could adversely effect how the user perceives the responsiveness of all the SaaS applications they have adopted.

The type of bandwidth controls available to schools include strict limitations on guest wireless, blacklisting of non-curriculum download sites and enabling educational filtering on multimedia sites. (for example: YouTube for Schools).

More sophisticated methods make of the traffic shaping features present on some of the more advanced firewalls by creating a bandwidth reservation for or by blocking or throttling specific application data streams (for example: BitTorrent, Spotify).

With bandwidth controls in place a 100Mbs connection would be sufficient to support a school of 500+ active GSfE users even allowing for additional services.

The relationship is between bandwidth requirements and number of users is fairly linear but as you trend towards the lower end of you can see some remarkable figures.

Perhaps even more surprising than the 800 user school is a smaller school in Guatemala that runs 125 users with 60 being heavy GSfE users on ‘laggy’ 4Mbs synchronous link.

This is not a recommendation but does give you some idea of what's possible.

Sunday 23 November 2014

A Design for a SaaS School.

In most schools SaaS services such as Microsoft Office365 and GSuite for Education have a supporting role for on-premise installations. SaaS is often seen as a convenient and cost effective way of extending a more traditional IT installation while at the same time fulfilling a number of requirements around mobility and remote access to messaging and data.

However the core service remains on-premise with SaaS acting as an extension to the solution.

A SaaS school reverses this design. In this model SaaS makes up the core provision with on-premise services reduced to a minimum. The basic design principle is that all services are delivered using SaaS unless there is a clear operational advantage why the service remains local.

Taking this to a logical conclusion the local install would comprise of five elements.

  • An Internet connection and terminating router.
  • An edge security appliance (firewall)
  • A local network service appliance.
  • A switched network optimised for mobility and SaaS
  • The end user devices.

Other design principles include:
  • The internet connection becomes the core facility for service delivery. For this reason it is elevated to the same level of importance in the design as the local network or storage  in more traditional approaches.
  • All data accessed locally must be replicated to a SaaS service using Google Drive, Microsoft OneDrive or a similar service. Data stored locally is limited to systems configuration and metadata.
  • Network functions are also supported by SaaS. This includes DNS, directory services and wireless management.
  • The solution is location independent. The resources available to the user are identical and behave in the same way regardless of how and where the services is accessed.
  • The solution is device and OS independent with a strong emphasis toward mobile.

The solution can incorporate either Microsoft Office365 or GSuite for Education as the principal SaaS service.

Although it may appear a radical approach a ‘server-free’ school based has existed as a working ‘proof-of-concept’ for a number of years as the pressures on education forced schools to start looking at more sustainable and affordable ICT options.

In the an early initiative in the southwest region of the UK that used Google Docs has been documented by Steve Moss in his personal blog

A major feature of this project is how forward thinking it was at the time and how much easier it would be to achieve with the resources available today.

As services such GSuite for Education are rolled out to schools worldwide the dominant model will be "server free" because the user experience for both staff and students is better and the on-premise alternative is unsustainable at scale.