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Werner Almesberger

2002-Sep-21 03:39 UTC

tcng version 8y

... is on SourceForge, http://tcng.sourceforge.net/#src

The main changes are that tcng''s HTB is now better at quantum
handling, and that tcsim now includes packet.def and ports.tc
automatically (via the new default.tcsim), like tcc uses
default.tc. The full change log is below, as usual.

The HTB change adds a very natural way for expressing a quantum:
instead of the somewhat obscure r2q, the quantum can be specified
as the time during which the class may monopolize the link.

The following two examples are equivalent:

htb {
    class (rate 1Mbps,quantum 1250B);
}

htb {
    class (rate 1Mbps,quantum 10ms);
}

A larger example for HTB with tcng is at the end of tests/htbng

I still owe you the completion of protocol-aware classification.
Well, next week :-)

- Werner

---------------------------------- cut here -----------------------------------

Version 8y (21-SEP-2002)
------------------------

- HTB quantum can now be specified in bytes or seconds (tests/htbquant)
- documented various parameter handling differences between tcng and tc
- added first example from HTB documentation to tests/htbng
- tcsim now uses default.tcsim to automatically include packet.def and
  ports.tc, similar to how tcc uses default.tc (tests/tcsdefinc)
- tcsim: added option -n to disable inclusion of default.tcsim
  (tests/tcsdefinc)
- updated tests/cbqroot, tests/cpp31, tests/defcbq, tests/defdsm, tests/ext,
  tests/idiomatic, tests/tcng-2j, tests/tcng-3i, tests/tcng-3t, tests/tcng-4n,
  and tests/trace to either invoke tcsim with -n, or to avoid using ip.def
- removed use of ip.def from all examples (examples/*, examples-ng/*)
- tcc/defaults.tc now resets the line number in order to work around strange
  cpps that embed -included file instead of including it, causing line numbers
  to be off by the length of the -included file (reported by "raptor")
- tcsim now stops SFQ and HTB timers at end (tests/tcstimstp)
- updated examples/sfq and examples-ng/sfq accordingly
- moved helper functions alloc, alloc_t, stralloc, and alloc_sprintf to
  tcng/shared/memutil.*
- added %c format to alloc_sprintf
- removed potential buffer overruns in tcsim/module.c and tcsim/cfg.l by using
  alloc_sprintf
- tcc did not complain when specifying "limit" in bytes and in packets
for FIFO
  qdisc (tests/tcng-8y)
- added awk to build prerequisites

-- 
  _________________________________________________________________________
 / Werner Almesberger, Buenos Aires, Argentina         wa@almesberger.net /
/_http://www.almesberger.net/____________________________________________/
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Jacob Teplitsky

2002-Sep-21 18:03 UTC

head link

RE: tcng version 8y

> 
> Message: 4
> Date: Sat, 21 Sep 2002 00:39:59 -0300
> From: Werner Almesberger <wa@almesberger.net>
> To: lartc@mailman.ds9a.nl
> Subject: [LARTC] tcng version 8y
> 
> ... is on SourceForge, http://tcng.sourceforge.net/#src
> 
> The main changes are that tcng''s HTB is now better at quantum
> handling, and that tcsim now includes packet.def and ports.tc
> automatically (via the new default.tcsim), like tcc uses
> default.tc. The full change log is below, as usual.
> 
> The HTB change adds a very natural way for expressing a quantum:
> instead of the somewhat obscure r2q, 
I think this statement requires a little more explanation.
> the quantum can be specified
> as the time during which the class may monopolize the link.
> 
> The following two examples are equivalent:
> 
> htb {
>     class (rate 1Mbps,quantum 1250B);
> }
> 
> htb {
>     class (rate 1Mbps,quantum 10ms);
> }
> 
According to 
http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm
=====================It might be good time to touch concept of quantums now. In
fact when more classes want to borrow bandwidth they are each given some number
of bytes before serving other competing class. This number is called quantum.
You should see that if several classes are competing for parent''s
bandwidth then they get it in proportion of their quantums. It is important to
know that for precise operation quantums need to be as small as possible and
larger than MTU.
Normaly you don''t need to specify quantums manualy as HTB chooses
precomputed values. It computes classe''s quantum (when you add or
change it) as its rate divided by r2q global parameter. Its default value is 10
and because typical MTU is 1500 the default is good for rates from 15 kBps (120
kbit). For smaller minimal rates specify r2q 1 when creating qdisc - it is good
from 12 kbit which should be enough. If you will need you can specify quantum
manualy when adding or changing the class. You can avoid warnings in log if
precomputed value would be bad. When you specify quantum on command line the r2q
is ignored for that class.
=====================

This is how tcng replaces a global parameter r2q with quantums :

Tcc allows inheritance of paramers so the following 

 htb  (quantum 1250B) {
     class (rate 1Mbps);
     class (rate 2Mbps);
 }

will have the same effect as:

 htb  () {
     class (rate 1Mbps, quantum 1250B);
     class (rate 2Mbps, quantum 1250B);
 }

So, in a way every parameter is "global".

If time is specified instead of bytes:

 htb  (quantum 10ms) {
     class (rate 1Mbps);
     class (rate 2Mbps);
 }

tcc will calculate the  quantum for each class based  it''s rate 
and it''s  time quantum inherited from the "global" time
quantum.


- Jacob
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LARTC - Sep 2002 - tcng version 8y

tcng version 8y

RE: tcng version 8y