[LARTC] Download and upload independency

[gypsy]

Diego Cabrero wrote:
> 
> Hello everyone:
> As it is known, when you limit uplink bandwidth it usually gets downlink
> bandwidth to a lower value.
> I just want to know what is the optimal configuration for eth1 and imq0
> according to some variables of  tc(HTB), txqueuelen, mtu, etc. to make
> these packet flows less independent on an ethernet based network.
> 
> Thank you in advance.
> 
> -Diego

Diego,

Since nobody else answered this, I'll give it a try.

I accelerate all small packets on the egress side because this sends the
ACK packets ASAP.  Doing this improves download speed.

I use 'quantum 1514', 'prio #' and 'burst #k' in my 'tc class add'
lines.  E.G.:
tc class add dev eth1 parent 1:1 classid 1:20 htb rate $RATE ceil \
  $CEIL burst 16k quantum 1514 prio 2

Make sure the sum of the rates is <= the parent rate.  Some say it is
better to patch htb to deque one packet at a time rather than 2.  I
don't.

Be sure you change your linux kernel source
  vi ~linux/include/net/pkt_sched.h
so it uses PSCHED_CPU because JIFFIES just does not cut the mustard.

I am just now implementing IMQ.  What a pain getting it to compile (bad
linux 2.4 patch)!  I can't say yet if this is the right approach, but I
intend to accelerate SSH and put everything else into a default bulk
class, adding an esfq qdisc:
~'parent 1:20 handle 20: esfq limit 64 depth 64 divisor 10 \
    hash dst perturb 20'
and then filter SSH by source and dest port 22 into accelerated 1:10.  I
want to shape the incoming flows by where the packets come from - but I
might change my mind after I try this :o

I looked at documentation on the DSL sites about tweaking, then at Oskar
Andreasson's tutorial to understand the /proc settings, but I can't find
my notes about what I changed.  I did increase buffer sizes, but I can't
recall anything further right now...  IIRC, most things were correct so
I did not change much.
--
gypsy