Lost packets? Slow ISP?

Dennis J. Streveler (strev@mobius.net)
Fri, 07 Jun 1996 07:30:27 -0700


At 09:21 PM 6/5/96 +0000, Jason Bachman wrote:
>
>If you are losing packets, you probably have a very slow internet
>connection, or your ISP is messing up somewhere.
>
>Regards,
>Jason Bachman
>jasonb@prolog.net

TO CU List and IPhone List,

"Losing packets" is inherent in the concept of the Internet, which is a
packet-switched network. That means that packets are sent on their way
HOPING they'll reach their destination sooner or later. This happens by
packets being routed from node to node. It is possible for some related
packets to take a route different from others in the same message. Due to
collision and time-outs and other factors, some packets do get lost along
the way. It may not be your ISP at all, but the "slowness" you describe is a
much more complex function.

There are two main protocols of the Internet:

1) UDP This method sends a packet on its way without ever learning whether
the packet is received. Most (all?) telephony and video applications use
this method because it is fast. Real-time applications can't wait to learn
whether packets are received or not, that would add very long delays to the
"turnaround" times which a user would experience.

2) TCP/IP This method does require acknowledgement of each packets receipt,
and will retransmit a packet when it recognizes that one got lost. It is
really not appropriate for "real-time" applications for the reason mentioned
above.

The Internet is going to get SLOWER before it gets FASTER, most people
predict. The level of traffic which it must serve continues to grow, and
telephony and video applications are very bandwidth-intensive applications.

At least now with IPhone4 you can easily SEE what is happening regarding
packet loss. "Red" immediately means "loss" in the statistics display. This
is a very helpful and useful feature, one which I think other applications
would do well to consider adding. When I see "red" in the IPhone4 statistics
display, I slow down, speak more distinctly and try to increase "context"
hoping this will help the other side understand more fully what I am saying.
Isn't it amazing how technology can/has/will alter our fundamental human
behavioral patterns! :)

Regards,
Dennis

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Dennis J. Streveler, Ph.D., | Internet: strev@mobius.net
Systems Consultant | CIS: 71036,1645
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