CDNETWORKS.COM
 THE INTERNET
 INFRASTRUCTURE
 GLOBAL NETWORK SERVERS
 NETWORK PERFORMANCE COMPARISONS
OUTLINE
AGENDA
CDNETWORKS.COM
THE GLOBAL INTERNET IS COMPLEX
CDNETWORKS.COM
PoP 3
PoP 2
PoP 1
Tier 3 Networks
(Multi-homed ISP)
IXC
Tier 1 Networks
Tier...
INTERNET RTT LATENCY
 DISTANCE
 SPEED OF LIGHT
70 ms
150 ms
LONDON
NEW YORK
500 ms SHANGHAI
GLOBAL INTERNET CHALLENGES
C...
GLOBAL INTERNET CHALLENGES
NETWORK PROBLEMS
 NETWORK OF NETWORKS BOTTLENECKS
 PACKET LOSS
 CONGESTION
 RETRANSMISSION
...
MULTIPLE RTTs FOR CONNECTION NEGOTIATION
GLOBAL INTERNET CHALLENGES
INEFFICIENT PROTOCOLS / RTT MULTIPLIER
•CHATTY PROTOCO...
DYNAMIC CONTENT
Changing / moving content
2 TYPES OF CONTENT
STATIC CONTENT
Base Web Page
and graphics
CDNETWORKS.COM
WITHOUT A CDN
USER
SLOW
CDNETWORKS.COM
Dynamic Content
logo.gif File
(Static Content)
BIG.pdf File
(Static Content)
ORIGIN
WITH A CDN (DYNAMIC CONTENT)
USER
SUPER HIGHWAY
“MIDDLE MILE”
Dynamic Content
ORIGIN
CDNETWORKS.COM
 These are common techniques
 Different CDNs use different techniques
 Most CDNs don’t share their specific techniques
...
TLS/SSL OFFLOAD
NO: SSL OFFLOADING
DWA EDGE
WITH: SSL OFFLOAD
EDGE SERVER WITH SSL CERTIFICATION ENCRYPTS & DECRYPTS ON IT...
DYNAMIC CONTENT
NO: CACHING, COMPRESSION,
CONN. POOLING OR KEEP ALIVE
DWA EDGE
WITH: CACHING, COMPRESSION,
CONN. POOLING A...
OPTIMALLY TUNED TCP LINKS
LONGRESPONSETIME
HIGH LATENCY
DWA Edge
LOW LATENCY
WITH LARGE WINDOWS, FAST RETRANSMIT, FINE GRA...
KEY TAKEAWAYS
Global Auction
Website Origin
3 Datacenters
CDN (CDNetworks)
 GLOBAL INTERNET CHALLENGES – RTT & LATENCY (S...
FOR MORE INFORMATION
VISIT CDNETWORKS.COM
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Tech Chat: Technical Review of Dynamic Content Acceleration

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CDNetworks' Tech Chat: Dynamic Acceleration

Have you ever wondered what the difference between dynamic and static content is, how dynamic content is accelerated and how a Content Delivery Network (CDN) can improve the performance of your dynamic web pages? This Tech Chat will provide you with a better technical understanding of dynamic content, the techniques used by a CDN to accelerate dynamic content and the advantages of using it for your website.

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  • Welcome to the latest CDNetworks’ Technical Chat. Today we will cover How to Accelerate Dynamic Content.

  • In the next 5 minutes (or so), we’ll go over the Internet, the challenges of fast, reliable content, and how a CDN can help you achieve these goals.
  • As background, the Internet is a collection of private networks that are interconnected with each other.

    Everything from big global Internet Service Providers (ISPs) like AT&T and Level3 to regional and local ISPs.

    They all interconnect with each other and must speak the same the language for content requests to traverse them.

    In most cases, content requests travel across multiple ISPs.




  • One of the biggest hurdles to great performance is distance.
    The further you are from the content, the longer it takes to see it.


    You have to make a request, then wait for the response.
    You can see the difference response times between cities that are close vs. those that are far away.

  • The second hurdle is reliability.
    There is so much traffic that sometimes a packet gets lost or dropped.


    This can happen at any point during send or receive.
    The web browser automatically notices this and requests it to be re-sent.
    This works, but causes slowness.

  • And third is that HTTP, what we all use to communicate over the Internet, is very “chatty”.

    There is a connection phase to ensure both sides are ready, then the file is transmitted (takes multiple round trips) and then the disconnection phase happens.


    The original designers created a very robust network that could survive multiple failures, but does not efficiently take advantage of today’s better performing networks.

    CDNs were designed to overcome all 3 of these challenges.



  • As background, there are 2 types of content, Static and Dynamic.
    The Twitter logo and graphics are static. They rarely change and we all see the same images.


    The Twitter feed, that is different for each of us, is Dynamic, always changing.
  • Here is a representation of how a web page works w/o a CDN.


    The user requests the home page, which results in individual requests to retrieve the logo image, the html, as well as big files and any dynamic content.
    This works just fine, but can be quite slow.

  • For dynamic content CDNs use a different approach.
    The CDNs that support Dynamic content, create a Super Highway to accelerate across the long distance, which is something that individual ISPs can’t do.


    In the next few slides, we’ll go into details on how this works.

  • The following slides are common techniques.

    Different CDNs use different techniques.

    Most CDNs don’t share their specific techniques.


    Bottom line: it’s the performance that matters

  • SSL traffic is increasing, due to the increasing importance of security across the internet.


    A CDN will host the SSL certificate at it’s edge server, which will speed up SSL negotiation, similar in concept to how caching works, but moving the content closer to the end user.


  • For the content itself, CDNs can use a number of techniques, like connection pooling and keep alive.


    In green on the right, the CDN will keep a couple of connections open from the CDN edge to the CDN shield and to the customer Origin. This means that when a request for new data comes in, a connection will be ready.

    In addition, CDNs make sure the connections stay open by sending “keep alive” messages to ensure the connection is open and performing at optimal levels.


  • The techniques show so far have dealt with service architecture.

    The protocols and defaults can also be optimized.

    This optimization can happen at the first, middle, and last mile.

    They optimizations can include: large windows, fast retransmit, optimal retransmission timeouts, and fast recovery.




  • In summary, CDNs were specifically designed to improve the performance, reliability and security of Internet content.

    Here is a typical example of an origin in a single datacenter with response times (in orange) at the top.

    In the middle, in blue, are response times for 3 datacenters (cloud hosting or co-location).


    And the performance and reliability of a global CDN that supports both dynamic and static acceleration is yellow.



  • www.cdnetworks.com
  • Tech Chat: Technical Review of Dynamic Content Acceleration

    1. 1. CDNETWORKS.COM
    2. 2.  THE INTERNET  INFRASTRUCTURE  GLOBAL NETWORK SERVERS  NETWORK PERFORMANCE COMPARISONS OUTLINE AGENDA CDNETWORKS.COM
    3. 3. THE GLOBAL INTERNET IS COMPLEX CDNETWORKS.COM PoP 3 PoP 2 PoP 1 Tier 3 Networks (Multi-homed ISP) IXC Tier 1 Networks Tier 3 Networks (single homed ISP) Tier 2 ISPs Global Network Providers Internet Users Broadband Providers Tier 2 Networks Regional ISPs, University Networks Transit Transit Transit Transit Peering
    4. 4. INTERNET RTT LATENCY  DISTANCE  SPEED OF LIGHT 70 ms 150 ms LONDON NEW YORK 500 ms SHANGHAI GLOBAL INTERNET CHALLENGES CDNETWORKS.COM SAN FRANCISCO
    5. 5. GLOBAL INTERNET CHALLENGES NETWORK PROBLEMS  NETWORK OF NETWORKS BOTTLENECKS  PACKET LOSS  CONGESTION  RETRANSMISSION CDNETWORKS.COM SAN FRANCISCO USER
    6. 6. MULTIPLE RTTs FOR CONNECTION NEGOTIATION GLOBAL INTERNET CHALLENGES INEFFICIENT PROTOCOLS / RTT MULTIPLIER •CHATTY PROTOCOL •TCP SLOW START •TENS OF BACK & FORTH ROUND TRIPS •30-50 RTTs FOR ONLY 1 PAGE •CONNECTION LOAD AT ORIGIN CDNETWORKS.COM SAN FRANCISCO FILE USER
    7. 7. DYNAMIC CONTENT Changing / moving content 2 TYPES OF CONTENT STATIC CONTENT Base Web Page and graphics CDNETWORKS.COM
    8. 8. WITHOUT A CDN USER SLOW CDNETWORKS.COM Dynamic Content logo.gif File (Static Content) BIG.pdf File (Static Content) ORIGIN
    9. 9. WITH A CDN (DYNAMIC CONTENT) USER SUPER HIGHWAY “MIDDLE MILE” Dynamic Content ORIGIN CDNETWORKS.COM
    10. 10.  These are common techniques  Different CDNs use different techniques  Most CDNs don’t share their specific techniques  Bottom line: It’s the performance that matters DISCLAIMER: DYNAMIC ACCELERATION CDNETWORKS.COM
    11. 11. TLS/SSL OFFLOAD NO: SSL OFFLOADING DWA EDGE WITH: SSL OFFLOAD EDGE SERVER WITH SSL CERTIFICATION ENCRYPTS & DECRYPTS ON IT’S OWN TO REDUCE ORIGIN LOAD ORIGIN ORIGIN CDNETWORKS.COM
    12. 12. DYNAMIC CONTENT NO: CACHING, COMPRESSION, CONN. POOLING OR KEEP ALIVE DWA EDGE WITH: CACHING, COMPRESSION, CONN. POOLING AND KEEP ALIVE CONTINUOUS CONNECTIONS BETWEEN EDGE & SHIELD; & SHIELD + ORIGIN REDUCE ROUND TRIPS FOR TCP OPEN & CLOSE CONNECTION DWA SHIELD PERSISTANTCONNECTIONS ORIGINORIGIN FILEPARTSNOTCOMPRESSED CDNETWORKS.COM
    13. 13. OPTIMALLY TUNED TCP LINKS LONGRESPONSETIME HIGH LATENCY DWA Edge LOW LATENCY WITH LARGE WINDOWS, FAST RETRANSMIT, FINE GRAINED RTO AND FAST RECOVERY DWA Shield LOW LATENCY CDNETWORKS.COM ORIGIN
    14. 14. KEY TAKEAWAYS Global Auction Website Origin 3 Datacenters CDN (CDNetworks)  GLOBAL INTERNET CHALLENGES – RTT & LATENCY (SLOW)  A CDN ACCELERATES DYNAMIC CONTENT CDNETWORKS.COM
    15. 15. FOR MORE INFORMATION VISIT CDNETWORKS.COM

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