Compared against the traditional model of distributed on-premises e-mail services, cloud based services (such as Gmail or Office 365) can seem attractive. However there are a number of considerations that need to be made, both for private or public cloud based messaging systems.
The advantages of public cloud services are well documented here http://www.cloudemail101.org/should-i-go-to-the-cloud/on-premise-vs-the-cloud however, there is another side that needs to be considered.
Public Cloud Services - disadvantages
Pure deployment can be quick, however, Orange have found that migration time may be increased. Customer experience has shown that in instances where there is use of delegation and rules in the Outlook client there is no porting of these to (public) cloud based platforms. Resource or rooms experience similar migration issues. This inevitably increases the number of support calls, which has an impact on the number of mailboxes that can be migrated per day with a limited resource on the service desk. Therefore migration time (and cost) is extended.
Another recent client experience proved impossible to transfer Public Folders to online SharePoint.
Should migration time be extended then the time that both services need to coexist needs to increase. The first rule of coexistence is to keep the coexistence time to a minimum - running two systems at the same time incurs additional cost, if the duration is extended then the cost overruns.
Our customers have experienced issues scheduling meetings, rescheduling meetings and accessing shared mailboxes – all of which can be minimised by careful planning, but this then causes further cost.
Integration with voice services is difficult with Public cloud based email services. Our experience with customers using public cloud email services has shown:
- Office 365 does not allow any server-side integration with third party PBXs.
- Integration with Cisco voice services has to be done at the client, meaning an additional client deployed to the desktop.
- Integration with Avaya voice is impossible.
- Therefore Lync will most likely exist as an island.
- Customers will find themselves responsible for managing a number of local telecom providers for SIP.
- Standard public cloud based email services mean access over the internet, implementing Quality of Service for voice is impossible.
- There may be compliance issues of unifying messaging, i.e. voice is not discoverable until voice mails are stored within the email environment.
Therefore, if companies are considering Unified Communications, functionality will be limited if a public cloud based email service is chosen.
Benefits of a Private Model
Retain Control the Schedule of Software Updates and the Roadmap
When subscribing to software-as-a-service the customer must follow the updates and patching schedule of the provider. This may prove to be inappropriate, especially where other systems are dependant on certain functionality of the email system.
For example, Microsoft were due to remove the Remote Call Control (RCC) API from OCS which would mean third parties would be unable to customise the way that OCS controls the desk phone. In the end Microsoft chose not to remove RCC, but there is always the danger that other functionality may be limited by future 'product enhancements' in the same way as RCC.
Deploy in Multiple Regions Allowing User to Server Better Performance
We have found that user to server email performance can be compromised when the service is centralised to one location and considerations are not made for accelerating or caching traffic. Even over private, MPLS based networks the latency from south-east Asia to Europe can be considerable and we would recommend a study to be made prior to changes being implemented.
Co-Locate E-Mail Server with Application Server, the IM Server, the SharePoint Server and the File System
Further to the above point of user access to the email server, it is important that Instant Messaging servers, file servers and SharePoint servers are located where low latency access is provided to all users. Orange has found this to be especially important to SharePoint and have previously designed services where Exchange is centralised and SharePoint regionalised to solve this particular issue.
Secondly, Orange believes from previous studies that document management applications have considerable interaction with the messaging service. For this reason alone, the email servers should be co-located with application servers.
Data privacy is of importance to many organisations. Therefore, we would recommend that data is located in a country sensitive to banking (and therefore information) privacy laws, such as Switzerland. Private cloud email services allow this flexibility.
Conclusion - Not Many Companies will go fully cloud in one go
To minimise risk we would recommend a more gradual approach to change. For example, build a private cloud service first, subsequently consider moving to a public offering in the future.