CS 4700 / CS 5700 Network Fundamentals Lecture 17.5: Project 5 Hints (Getting a job at Akamai) Revised 3/31/2014

Review: Optimizing Performance 2 Key goal Send clients to server with best end-to-end performance  Performance depends on  Server load  Content at that server  Network conditions  Optimizing for server load  Load balancing, monitoring at servers  Generally solved

DNS Redirection 3

How to fill in DNS response 4  Geolocation  GeoIP database provides IP->location  Which IP address should you lookup?  How should you use the location?  Active measurement  Ping latencies  What should you probe?  iPlane dataset contains useful information  Passive measurement  How can you measure RTT without any active probes?

Caching Web server 5  Space on each account is limited  10MB for a corpus that much larger  Distribution of requests to content: 03/ 03/  General approach  Examine GET parameters  Check database for content If present, serve from cache If not, fetch from origin and (possibly) cache

Running replicated services 6  Step 1: Debug on a single machine interactively  Step 2: Develop scripts to automate running  Step 3: Test on one server and make sure everything works properly  Step 4: Test on two servers in a fully automated deployment  Step 5: Deploy on all servers

Other notes 7  You cannot cache at the origin server, don’t bother trying to log in there  DNS server will be rebooted daily  If you test your code on any other CCIS machine, your DNS responses will be blocked  Getting measurement data to DNS server  What can you reuse to do this?  HTTP GET messages generated via wget  DNS lookups performed using dig  Set up SSH keys for your accounts on EC2  Only way to get non-interactive commands