technology for backbone web caching n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Technology for Backbone Web Caching PowerPoint Presentation
Download Presentation
Technology for Backbone Web Caching

Loading in 2 Seconds...

play fullscreen
1 / 10
osbourne

Technology for Backbone Web Caching - PowerPoint PPT Presentation

103 Views
Download Presentation
Technology for Backbone Web Caching
An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Technology for Backbone Web Caching Peter B Danzig Network Appliance November 1998

  2. Speakers Peter Danzig -- Network Appliance “Scaling Cache Deployments” Shirish Sathaye -- Alteon Networks “Scaling w/L4-Switches” James Aviani -- Cisco “Scaling WCCP” Bill Maggs -- MCI/Worldcomm “Routing and Caching” Ed Kern Digex “Report on Digex cache deployment”

  3. Rules of thumb for Scaling Individual Cache Nodes Peter B Danzig Network Appliance November 1998

  4. Scaling Individual Cache Nodes • Rule of thumb resources required per megabit • Simultaneous TCP Connections 500 • Disk Needed 4 GB • Disk Arms Needed 1/2-1/3 • Memory 32 MB

  5. Simultaneous Connections Little’s Law: N = l W W: Average time to fetch a web page: 4-10 Seconds l: URLs/Second: 25 per megabit N: Number of TCP connections N = 2 * 25 * 10 = 500 connections/megabit

  6. Disk Arms Keep disks below 50% busy A cache behind a cache sees random references Assume all references require 1 disk/ops Depending on OS, a single disk can achieve 50-200 operations per second Per megabit: 25 ops/S * 2 (for head room) yields anywhere from 1 disk to 1/4 disk per megabit

  7. Disk Space A megabit link can draw 9GB/day Peak to average load is about 4X So a 9GB disk holds the entire reference set of 4-days of operation. Assume 1/2 of references are already cached or are non-cachable…. Use 4GB of disk per megabit

  8. Memory Each megabit means 500, dual 8 KB TCP buffers: 8 MB Proxy state for 500 connections @ 32KB: 16 MB Disk buffer pool: 8MB Leads to 32MB/megabit

  9. CPU • Depends on the manufacturer and OS release • For example: • C720 running NetCache-3.3: 25 mbits/s • C760 running NetCache-3.3: 37 mbits/s

  10. Aggregating Cache Nodes • Currently have two technologies for clustering cahe nodes • L4 Switches • Alteon, Arrowpoint, Foundry, and RND • WCCP • Cisco routers and WCCP licensees