Thread: Still have packet loss on my Samsung STB
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Old 29-11-2004, 11:59   #11
rdhw
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Location: Cambridge
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Re: Still have packet loss on my Samsung STB
Quote:
Originally Posted by Dessimat0r
Even if I limit my upload to 15k/s, I still get packet loss -- images sometimes do not load, etc. It is not a solution.
Ultimately, the only way a bandwidth cap can be enforced is by dropping packets. The CMTS/UBR will at first try to enforce the cap by delaying packets in a buffer (or leaky bucket), and hoping that the flow control properties of TCP will cause the rate of arrival of data to slow down. But if the packets continue to flood in, the leaky bucket will overflow and the overflowed packets will be lost. Maybe (or maybe not) this is what is happening to you.

Much depends on your TCP Receive Window, or RWIN, setting. If you have an over-large RWIN setting, it will eventually be impossible for the CMTS/UBR to delay/hold complete TCP Windows (for each of your incoming TCP sessions) in its leaky bucket, and you will lose incoming data. I suggest you run the Tweak Test at http://www.broadbandreports.com/tweaks which will report your active RWIN setting.

Another potent cause of packet loss could be an ethernet duplex mismatch between your STB and the device connected to it. What are the ethernet speed and uplex settings in force there?
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