Hi all -
We have four sites in South Africa (SA) who share a combined 5Mbps down/10Mbps up sattelite link back to a centralized infrastructure in London which houses a single CAHT server and mailbox server (see attached Visio). 95% of the company works primarily in SA where the options for connectivity are limited and pricey. In addition, staff in SA have 5 weeks on/2 weeks off work schedule so when they are in leave they could be connecting from anywhere in the world. ALL traffic (web, mail, etc.) is currently being forced up and down the link.
In other words, if I am site A in SA and send an email to site B in SA the email must travel up the link to London to our CAHT server and the recipient must retrieve it from the MB server also located in London.
This presents several issues. First and foremost it causes users who are sending attachments to see the status bar in Outlook as the mail is being transferred up.
Our idea is to place a second CAHT in SA so that at least when a user sends a mail it 'appears' to be instatntly delivered (obviously it would simply be queued on the SA CAHT until it gets delivered to the London CAHT). This would be our smoke and mirrors approach to ease end user consternation as far as sending email is concerned.
Secondly, we are wondering if placing a secondary MB server SA and configure DAG replication would be of benefit. Of concern is saturatnig the link with replication traffic. Is it possible to pre-populate a copy and fly it into country and connect it to a newly built MB server? If a user is on leave and connects with Outlook anywhere to London I assume that they would then be connected to their MB copy in London rather than their home server in SA should we deploy one there.
Is it safe to assume that the amount of replication traffic we would see would be equal to the change in MB database size? Can we schedule it? Are there any metrics out there for what we can expect to see if we go that route?
In a few weeks time we will have a microwave network in place in SA connecting the local sites at 100Mbps. That should at least allow SA generated emails that are destined for another SA mailbox to be delivered in a timely fashion.
Clearly we are hobbled by the hard fact that connectivity back to London is limited to sattelite communications. We've been tossing and turning tryng to figure out how to improve the user experience and I wanted to shoot this out to the wider community to see if anyone has any outside-of-the-box ideas.
I apologize for the length of this question but I want to cover my bases before suggesting a solution or telling the CIO that he needs to dump another 20,000£ a month for additional satteliet bandwidth.
Many kind regards!
(attached is an overview of the infrasructure)