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Why Is 1% Loss Significant?
A video feed does not need much speed, only from 128K to 3 Mbps,
but any amount of loss causes problems. H.323, the application
that Doug was using to give his presentation, is an example
of an application family that does not tolerate loss. Loss is
significant to any real-time application, except voice. This
affects remote labs, video conferencing, and anyone trying to
do high bandwidth over long distance (because of current TCP
characteristics). There are several new high-speed TCP algorithms
under development that may fix this problem but it will be at
least 3-5 years before they are in common use. The concept of
zero-packet loss tolerance by some application families needs
to be communicated more clearly to a broad audience.
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to Case Study
t
is a cakebox? It is a small, inexpensive PC
running Linux. It is configured such that, when you plug it
into a DHCP-enabled Ethernet port and give it power, it registers
its presence with an LDAP server where it logs its current
IP address so you can “find” it. You can then
connect to it remotely and run a series of network utilities
(like Iperf, traceroute, and pchar). Cakeboxes were developed
by Internet2 to test H.323 video conferencing capabilities
and have been used for a variety of other end-to-end performance
tests. Instructions on “building” a cakebox are
available to member institutions upon request.
DHCP-enabled Ethernet port and give it power, it registers
its presence with an LDAP server where it logs its current
IP address so you can “find” it. You can then
connect to it remotely and run a series of network utilities
(like Iperf, traceroute, and pchar). Cakeboxes were developed
by Internet2 to test H.323 video conferencing capabilities
and have been used for a variety of other end-to-end performance
tests. Instructions on “building” a cakebox are
available to member institutions upon request.
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