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Author Topic: PCR (Peak Cell Rate), SCR (Sustainable Cell Rate) and MBS  (Read 7084 times)


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PCR (Peak Cell Rate), SCR (Sustainable Cell Rate) and MBS
« on: March 16, 2008, 12:46:30 PM »

i am using officeconnect 3com wireless router for connecting to adsl on BT.
i can see these options.
the help couldnt give me much info .
does any one knows what these should be set on.
at the moment it is set to pcr=400 scr=400 mbs=100
if i change these thing what gonna happen?>

i am having problem with internet connection on all computyers on my network.
i am suspecting a noise or a falut.
some times poeple wait to download a file. for example 5mg and on 99% it stops and moved no forward.
the files doesnt get downloaded fully.

most of times i have to refresh the page to open. the internet is not slow. but it takes 2-3 time refreshing for pages to load properly.


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Re: PCR (Peak Cell Rate), SCR (Sustainable Cell Rate) and MBS
« Reply #1 on: March 16, 2008, 03:34:53 PM »

TBH not something I'd mess with since it would appear to be in relation to the ATM configuration commands and way over my head - sorry.
The only ATM config that we normally have to set is (for BT) is VPI = 0 VCI = 38

Theres a bit more info in the 3com CLI manual

output-pcr: Peak rate of ATM cell output in Kbit/s. For the value ranges of this parameter, see Value ranges of output-pcr.
output-scr: Sustainable rate of ATM cell output in Kbps. Its value ranges are the same as those of output-pcr.
output-mbs: Maximum burst size of ATM cell output, i.e., the maximum cache size of ATM cell output at the interface in cell number.

See ATM configuration Page 343 onwards.

Theres a discussion on files stopping at 99% here which may give some clues where to look..

Something else I would also check out is the maximum no of IP sessions which has been known to give some people problems in the past. 
Particularly if you are using applications which utilise multiple sessions such as p2p.
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