[LARTC] Where does the Bandwidth Management taking place after/before

[LARTC] Where does the Bandwidth Management taking place after/before

[Srikanth W]

Hi!
 
I want to know exactly how the packet flow is occuring in BW management?

and 

Where does the Bandwidth Management taking place after/before routing?

Kindly let me know asap.

tnr,
Srikanth

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Re: [LARTC] Where does the Bandwidth Management taking place after/before

[Tobias Geiger]

AFAIK:
local stuff: Application -> IPTABLES (OUTPUT) -> ROUTING -> QDISC
	routing stuff: IPTABLES (PREROUTING/FORWARD) -> ROUTING -> 
IPTABLES-POSTROUTING -> QDISC

these iptables-chains do sometimes a little wired stuff, depending on 
the jump-target/Chain (especially PREROUTING/NAT/...) sometimes 
routing-code is called to determine the route for iptables, but AFAIK 
ALL packets pass after the iptables-code the routing-code and ALWAYS as 
a LAST station the qdisc.
off course only outgoing stuff. incoming is more or less :) other way round.

Greetings

Tobias

Srikanth W wrote:
> Hi!
>  
> I want to know exactly how the packet flow is occuring in BW management?
> 
> and 
> 
> Where does the Bandwidth Management taking place after/before routing?
> 
> Kindly let me know asap.
> 
> tnr,
> Srikanth
> 
> _______________________________________________
> LARTC mailing list / LARTC@mailman.ds9a.nl
> http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
> 
> 


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Re: [LARTC] Where does the Bandwidth Management taking place

[Martin A. Brown]

Srikanth,

 : I want to know exactly how the packet flow is occuring in BW management?

Eh?  Seems a bit of a general question....can this not be answered by some
study of the queueing discipline you are using?

If you don't know where to start reading about the queueing discipline you
are using, start at http://lartc.org/ and http://www.docum.org/ and, of
course, a google search.

 : Where does the Bandwidth Management taking place after/before routing?

Study the kernel packet travelling diagram, and you'll have a better idea
of the answer to your question.

  http://www.docum.org/stef.coene/qos/kptd/

The short answer is:

 - egress traffic control occurs after all of the IP filtering, mangling
   and rewriting
 - ingress traffic control occurs after iptables PREROUTING hooks (if
   you are using iptables) or ipchains input (if you are using ipchains)

-Martin

-- 
Martin A. Brown --- SecurePipe, Inc. --- mabrown@securepipe.com

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