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[Fwd: "mask" in tc commands]



Joao Reis wrote:
Khalid Oudassi wrote:
hi,
Hi
 
can anyone tell me what os the signification of the keyword "mask" in  tc commands
and why it is there?
The main objective of the mask keyword is to mask the bits of te TOS byte by a certain number. For example if you mask the TOS byte with a value 0x3 you mask out bits 6 and 7.

The mask keyword is widely used when we need to change the DSCP byte on diffserv .

 
Example:  tc class change dev eth0 classid 1:1 dsmark mask 0x3 value 0xb8

"This instructs the dsmarker to remark the DSCP of classid 1:1 by first masking out bits 6 and 7 then ORing that with value 0xb8. Note that: This is equivalent to ignoring the ECN bits, and setting the code point value to 0x2e (DSCP for EF)"--- This statment is on Differentiated Services on Linux by Werner Almesberger, Jamal Hadi Salim and Alexey Kuznetsov.

I advise you to read it...

 
is there any thing to have with the tos byte?
are all the values possible to set for the tos byte in Linux?
please help
and thanks tu everybody
-- 
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Joao Brandao Reis
email: ee94002@reinolinux.fe.up.pt
WWW: http://reinolinux.fe.up.pt/~ee94002/
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-- 
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Joao Brandao Reis
email: ee94002@reinolinux.fe.up.pt
WWW: http://reinolinux.fe.up.pt/~ee94002/
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