November 17, 2008
Amazon has finally opened the doors of its new CDN (Content Delivery Network) called CloudFront. But instead of building a completely new product it has interestingly expanded its S3 network to include content replication for lower latency content delivery. By not reinventing a whole new way of uploading data to the CDN network, Amazon has seriously cut down the cost for end users to try out this technology.
Most of the CDNs I've investigated do very well with static content which needs to be periodically refreshed somehow.
There is at least one service from Akamai called WAA - Web application accelerator which seem to understand the importance of accelerating extremely dynamic content using intelligent routing and closer points of presence to end user. WAA doesn't put the content closer to the end user, but provides an extremely efficient conduit for this traffic where Akamai controls both ends network by placing a POP in front of the client and the server. By doing this Akamai can take control of TCP/IP window sizes within its network and provide a low latency, higher bandwidth response to the customer. In addition to all this Akamai also provides an option to cache some data ( as defined in the HTTP headers, or WAA configuration ) to be cached for a longer duration.
Though Amazon might be doing replication as well, it may be closer to the Akamai's WAA model than what you thought. Its kind of obvious that if the data is going to change all the time, there has to be some kind of master-slave concept, and its also clear that if many people are accessing that data around the world it has to be transported through a very efficient high bandwidth network to the various Amazon Points of presence around the world. And finally just like the Akamai's WAA model, it probably does the cache content to serve the content directly from its local cache incase the object hasn't changed on the master since the last time it was retrieved.
A month ago I went shopping, looking for alternatives to Akamai's WAA and didn't find anyone. I suspect CloudFront changes that a little bit. One significant difference between Amazon and most CDNs out there including CloudFront is that there is relatively very little work which needs to be done by the developer to integrate with WAA. This is not true with most CDNs, and certainly not true for CloudFront if you are not already on S3. But it does change the dynamics of this industry.
September 27, 2008
August 03, 2008
Mozilla Firefox 3.0 throws a warning for self-signed certificate, and makes you do a couple of extra clicks to see the contents. Though some think its bad, I'm not sure what the fuss is all about. There are two reasons for the certificates. One is to encrypt the traffic, and the other to make sure no one intercepted your traffic using some kind of man-in-the-middle attack. One cant guarantee the second objective until a respected third party can sign/vouch the certificate. This is why these organizations exist.
If this is such a big issue, the right approach should be for someone to setup a free certificate registry. There are few out there today like startcom, but the browser support on such registries is currently unimpressive.
Speaking on behalf of the 99% of the Internet population who doesn't understand the significance of SSL certificates, I think the decision Mozilla took is courageous and admirable, and other browsers should do something similar if they don't already.
June 03, 2008
There are a lot of traceroute programs out there. This one called WinMTR was recently recommended by Akamai support during one of the troubleshooting sessions. Its based of another Linux tool called mtr (Matt's traceroute) which is another one I had never heard off.
I liked it so much, that ended up making an enhanced web interface to it. Check it out here at Webtrace.info.
Webtrace provides extra networking information which is really helpful for folks who are trying to investigate networking issues. There are a lot of hyper links which allows them to quickly drill down into issues (like who is loosing packets).