Mechanisms that directly influence network throughput

NETWORK WORLD NEWSLETTER: STEVE TAYLOR AND JIM METZLER ON WIDE
AREA NETWORKING
06/28/05
Today's focus: Mechanisms that directly influence network
throughput

Dear networking.world@gmail.com,

In this issue:

* TCP flow control
* Links related to Wide Area Networking
* Featured reader resource
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This newsletter is sponsored by Hewlett Packard
The Business Case for Adopting Blade Systems in the Data Center

HP ProLiant Blade Systems: The Business Case for Adopting Blade
Systems in the Data Center. When making a purchase decision,
blades should be considered as an integrated, consolidated
infrastructure-or a complete system-that includes servers,
storage, networking and power. Learn how HP's blade system
represents a new approach to infrastructure that can accelerate
the integration and transformation of your data center.
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Today's focus: Mechanisms that directly influence network
throughput

By Steve Taylor and Jim Metzler

We previously wrote a newsletter about the TCP window size (see
link below). The responses we received to that newsletter
convinced us that we should occasionally devote future
newsletters to detailing other WAN optimization technologies.

With that in mind, the next three newsletters will discuss some
flow and congestion control mechanisms that are used within TCP.
One of the reasons that these mechanisms are important is that
they directly influence network throughput.

In a perfect world, there would be no need for flow or
congestion control mechanisms. The sending device would transmit
packets as quickly as it could, the packets would all be
delivered in order and without unexpected delay, and the
receiving device could quickly process as many packets as the
sending device could send.

However, since that is not a realistic situation, TCP has
mechanisms that account for two of the key factors that
determine the performance of a TCP/IP network. Those factors
being the ability of the receiving device to accept data, and
the amount of congestion that exists within the network.

In order to account for the ability of the receiving device to
accept data, TCP has a flow control mechanism for each
connection. Each segment header contains a field called
"advertised window" that indicates how many additional bytes of
data the receiver can accept. The sending device is not allowed
to send more bytes than the advertised window.

The next newsletter will outline some of TCP's congestion
control mechanisms and will discuss their relationship to flow
control.

RELATED EDITORIAL LINKS

Uncovering the sources of WAN connectivity delays
Network World, 05/05/05
http://www.networkworld.com/nlwan2881

TCP Performance Issues
http://www.networkworld.com/nlwan2882

An Overview of TCP/IP Protocols and the Internet
http://www.garykessler.net/library/tcpip.html

Cisco puts focus on Web services, starting with AON
Network World, 06/27/05
http://www.networkworld.com/news/2005/062705-cisco.html?rl

Cisco readies upgrade for 10000 series
Network World, 06/27/05
http://www.networkworld.com/nlwan2883
_______________________________________________________________
To contact: Steve Taylor and Jim Metzler

Steve Taylor is president of Distributed Networking Associates
and publisher/editor-in-chief of Webtorials. For more detailed
information on most of the topics discussed in this newsletter,
connect to Webtorials <http://www.webtorials.com/>, the premier
site for Web-based educational presentations, white papers, and
market research. Taylor can be reached at
<mailto:taylor@webtorials.com>

Jim Metzler is the Vice President of Ashton, Metzler &
Associates, a consulting organization that focuses on leveraging
technology for business success. Jim assists vendors to refine
product strategies, service providers to deploy technologies and
services, and enterprises evolve their network infrastructure.
He can be reached at <mailto:jim@ashtonmetzler.com>
_______________________________________________________________
This newsletter is sponsored by Hewlett Packard
The Business Case for Adopting Blade Systems in the Data Center

HP ProLiant Blade Systems: The Business Case for Adopting Blade
Systems in the Data Center. When making a purchase decision,
blades should be considered as an integrated, consolidated
infrastructure-or a complete system-that includes servers,
storage, networking and power. Learn how HP's blade system
represents a new approach to infrastructure that can accelerate
the integration and transformation of your data center.
http://www.fattail.com/redir/redirect.asp?CID=107273
________________________________________________________________

ARCHIVE LINKS

Archive of the WAN newsletter:
http://www.networkworld.com/newsletters/frame/index.html
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