[LARTC] Use of qcdisc+htb

[LARTC] Use of qcdisc+htb

[Alvaro Motta]

Hi folks.

This message may be a bit verbose and not as techie as the ones I've
seen in this list, but describing the scenario will save a lot of
messages.

Scenario:

A building with 17 floors, each floor with 24 offices (totals 408
offices) connected to the backbone through a border switch (1 vlan for
each office). The offices can lease bandwidth of 64k, 128k, 256k,
512k, 1M and 2Mbps, according to their needs. We have 3 links to the
internet, 2Mbps each. Currently, we use cisco's bbsm to handle the
task of allocating the leased bandwidth for the vlans.
Problem: bbsm never performed as expected. It freezes, disconnect
users, reboots for itself leaving us in an awkward situation. After
wasting precious time with cisco and it's product, we decided to move
to another solution and since the boss is an enthusiast of open source
software, we decided to go for a linux based solution.
We found that queueing discipline may be the solution.
The question: are we correct, I mean is qdisc+htb the right thing to
be used in such a scenario? Has anyone out there seen a linux box
handling so many networks?
As I go deeper in this subject, I will come to share my thoughts and
doubts with you guys.

Hope to hear from you. Have a good one.


AL
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Re: [LARTC] Use of qcdisc+htb

[rsenykoff]

> Scenario:
> 
> A building with 17 floors, each floor with 24 offices (totals 408
> offices) connected to the backbone through a border switch (1 vlan for
> each office). The offices can lease bandwidth of 64k, 128k, 256k,
> 512k, 1M and 2Mbps, according to their needs. We have 3 links to the
> internet, 2Mbps each. Currently, we use cisco's bbsm to handle the
> task of allocating the leased bandwidth for the vlans.
> Problem: bbsm never performed as expected. It freezes, disconnect
> users, reboots for itself leaving us in an awkward situation. After
> wasting precious time with cisco and it's product, we decided to move
> to another solution and since the boss is an enthusiast of open source
> software, we decided to go for a linux based solution.
> We found that queueing discipline may be the solution.
> The question: are we correct, I mean is qdisc+htb the right thing to
> be used in such a scenario? Has anyone out there seen a linux box
> handling so many networks?
> As I go deeper in this subject, I will come to share my thoughts and
> doubts with you guys.
> 
> Hope to hear from you. Have a good one.
> 
> 
> AL
> _______________________________________________

LARTC is being used in University environments with even higher bandwidth 
usage, so yes, you can do it.

The multiple links may complicate things if you don't want to explicitely 
assign a VLAN to a link. While balancing across the links is not that 
difficult, combining the balancing with shaping to guarantee x amount of 
bandwidth could be difficult.

Do you want to simply use HTB to limit rates for each office? If so, this 
should work very well. You'll just need to build the routes to specify 
which network goes to which internet connection. Or, you could use a 
separate box for each internet connection if you break out the VLANs 
earlier.

FYI, I'm using a Pentium Pro 200 to shape traffic on a 3Mb/3Mb connection 
using CBQ for VoIP, Video, Citrix, and Bulk.

HTH,
-Ron
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Re: [LARTC] Use of qcdisc+htb

[Peter Surda]

On Thu, 14 Jul 2005 10:14:37 -0300 Alvaro Motta <alvarolmmotta@gmail.com> wrote:

>Hi folks.
Hi,

>This message may be a bit verbose and not as techie as the ones I've
>seen in this list, but describing the scenario will save a lot of
>messages.

>Problem: bbsm never performed as expected. It freezes, disconnect
>users, reboots for itself leaving us in an awkward situation.
First of all although I personally also think cisco's are not very good for
other things than routing, experience tells me that problems are often caused by
misconfiguration. I'd check out with an experienced cisco professional.

>The question: are we correct, I mean is qdisc+htb the right thing to
>be used in such a scenario? Has anyone out there seen a linux box
>handling so many networks?
I expect you want to use many htb classes with the same parent. I have seen a
reports that this causes problems when you really have a large class number
(several hundred), but again, this may have been caused by misconfiguration.

If you adapt your requirements however (every IP is handled equally), you can
use WRR, it has been proven to work without problems under even larger number of
clients (1400) and bandwidth (16Mbit). For an example see here:
http://mailman.ds9a.nl/pipermail/lartc/2005q2/016500.html

If you don't want to adapt, once upon a time I wrote a management tool for an
ISP with requirements similar to yours. Although I tuned it for performance and
it seems to work well, as far as I know there are only a couple of dozen users,
I don't know how it would behave if it was used with several hunderd users.

>AL
Yours sincerely,
Peter
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Re: [LARTC] Use of qcdisc+htb

[Peter Surda]

On Thu, 14 Jul 2005 17:24:00 +0200 Peter Surda <surda@shurdix.com> wrote:

>If you don't want to adapt, once upon a time I wrote a management tool for an
>ISP with requirements similar to yours. Although I tuned it for performance and
>it seems to work well, as far as I know there are only a couple of dozen users,
>I don't know how it would behave if it was used with several hunderd users.
Update: I obtained some data from the mentioned ISP:
- Backbone: 16Mbit
- average transfer 700kB/s (5600kbit/s)
- about 20 users
- CPU Celeron 333
- no performance problems noticeable

The only unanswered question remains the user count (20 vs 400 is not really
comparable).

Yours sincerely,
Peter
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Re: [LARTC] Use of qcdisc+htb

[Paweł Staszewski]

Hello

I have 40Mbit/s internet uplink
Average transfer 25Mbit/s
- 3957 users
On machine: 
- CPU 3.2GHz P4 +HT enabled
- 2GB RAM
- Intel GB cards

Machine is doing nat/dnat for each user so there is 3957 DNAT/SNAT ip pairs (private to public and vice versa)

Machine load is 0.1 avg

And no any problems :)

 
 

 
On Thu, 14 Jul 2005 17:24:00 +0200 Peter Surda <surda@shurdix.com> wrote: 
 
>If you don't want to adapt, once upon a time I wrote a management tool for an 
>ISP with requirements similar to yours. Although I tuned it for performance and 
>it seems to work well, as far as I know there are only a couple of dozen users, 
>I don't know how it would behave if it was used with several hunderd users. 
Update: I obtained some data from the mentioned ISP: 
- Backbone: 16Mbit 
- average transfer 700kB/s (5600kbit/s) 
- about 20 users 
- CPU Celeron 333 
- no performance problems noticeable 
 
The only unanswered question remains the user count (20 vs 400 is not really 
comparable). 
 
Yours sincerely, 
Peter 
 
 

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Re: [LARTC] Use of qcdisc+htb

[Peter Surda]

On Fri, 15 Jul 2005 11:55:34 +0200 "Pawe³ Staszewski" <pstaszewski@artcom.pl>
wrote:

>Hello
Hello

>I have 40Mbit/s internet uplink
>Average transfer 25Mbit/s
>- 3957 users
[cut]
Well, the question is what kind of TC-setup you have. Do you have a separate HTB
class for every user?

Yours sincerely,
Peter
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