* A suggestion to address the e-mail problems of remote users
Last time, we raised the issue of the of e-mail problems for remote office users. Today, one approach to a solution. One new technology that’s gaining acceptance is the idea of e-mail acceleration and caching. This technique places a caching appliance at the central IT facility and typically smaller versions of the appliance at each remote site. The strategy here is to store attachments at the main site, sending them across the WAN only when they are really needed. When that occurs files go out over the WAN in compressed format using a WAN-optimized protocol. The attachments are then cached at the branch office on a small appliance. Whenever an attachment is sent to multiple recipients at the office, it only crosses the WAN once; local redundant copies will be served out of the local caching appliance.
Last time, we raised the issue of the of e-mail problems for remote office users. Today, one approach to a solution.
One new technology that’s gaining acceptance is the idea of e-mail acceleration and caching. This technique places a caching appliance at the central IT facility and typically smaller versions of the appliance at each remote site. The strategy here is to store attachments at the main site, sending them across the WAN only when they are really needed. When that occurs files go out over the WAN in compressed format using a WAN-optimized protocol. The attachments are then cached at the branch office on a small appliance. Whenever an attachment is sent to multiple recipients at the office, it only crosses the WAN once; local redundant copies will be served out of the local caching appliance.
The appliances maintain their own file systems, and set pointers between e-mail messages and their attachments (now however, the pointers reference the cached copies of attachments, allowing multiple e-mails to share an attachment). As a result, organizations keep e-mail servers consolidated at the datacenter where they can be managed most effectively; remote users get the performance of a local mail server, and bandwidth requirements are minimized.
Today, when a user at a remote office receives a 10M-byte PowerPoint file from headquarters and then decides to forward the attachment to 10 members of his team, the original file is sent back to the datacenter and assigned to each team member’s mailbox. Each recipient now has a discreet copy of the file, and each copy must be accessed over the WAN. The result of this sending and forwarding is that the original 10M-byte file has now taken up 120M bytes of bandwidth (10M bytes for the original user to receive it, another 10M bytes to send it back to the data center, and then 10M bytes for each of the 10 team members to retrieve it again). Ask yourself how many times each day this happens in your company.
Let’s look at how a caching solution might improve things (I built this example using Tacit Networks’ Ishared Exchange http://www.tacitnetworks.com).
With local caching, things are quite different. When the remote office user first clicks on the icon to open the original 10M-byte file, it has already been significantly compressed – perhaps to below 3M bytes – and has been sent over the WAN via a WAN optimized protocol. Performance is significantly improved already. More significantly, when the file is forwarded to the 10 team-members, the original copy no longer moves across the WAN. Instead, the forwarding message points to the copy of the presentation that is stored in the cache.
The result of this is that when each of the 10 members clicks on the file icon in the message, it is opened and pulled from the local cache. In the end, the original 10M-byte file actually takes only 3M bytes of bandwidth for both the initial transmission and for the forwarding to the rest of the team. The original 10M-bytes was compressed and sent to Fred, then each of the other recipients read the attachment from the local cache.
The result: after the first send there is no further WAN involvement, everyone gets performance from a local server, the bandwidth used is a fraction of what traditional methods would have needed.
Next week, more on e-mail.
