Mailing List Archive: AW: Zebra Router???

AW: Zebra Router???

Apr 20, 2003, 6:30 AM

Post #1 of 4 (3512 views)

Hello Tom,

It is an interesting question how much traffic the box can handle.
During normal operations I'd say that 500 Mbits/sec should be possible,
but the even more interesting question would be how much PACKETS PER
SECOND the box can handle ?
We've got the problem that our linux-boxes are freezing when an attack
with let's say only 40 megabits but hundreds of connections or packets
per second are incoming.
Maybe there's something wrong with our kernel and/or TCP-Settings.

Is there someone on the list who can tell me how to opzimize the linux
kernel and especially the tcp-settings in /proc ??

Maybe the ZNOG-group can help - I've cross-posted the message, so please
reply on nanog or via pm.

Happy easter,
Gunther

-----Ursprüngliche Nachricht-----
Von: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] Im Auftrag von
Tom Daly
Gesendet: Sonntag, 20. April 2003 07:59
An: nanog@merit.edu
Betreff: Zebra Router???

Hi All,
I'm trying to find out what peoples experiences regarding the throughput
of Zebra on a FreeBSD Box.

My configuration is as follows:

Intel Pentium III 1.40G
1 Gig RAM
2x <Intel Pro 10/100B/100+ Ethernet> (one internal, one external) on
board.

This box is running as a simple static router, i.e. one subnet on the
inside, Internet feed on the other side. No BGP, no RIP, no OSPF. Pretty
simple, eh?

So the goal is to know the bandwidth limitation of this router. Any
ideas? I've heard numbers of 35Meg, 40 Meg, etc, however, I have not
recieved a good reason backing it up. Can anyone offer some input on
this?

Regards,
Tom Daly

--
Tom Daly
tom@dyndns.org
Chief Infrastructure Officer
Dynamic DNS Network Services
http://www.dyndns.org/

Re: AW: Zebra Router??? [ In reply to ]

paulj at alphyra

Apr 20, 2003, 12:35 PM

Post #2 of 4 (3353 views)

Permalink

On Sun, 20 Apr 2003, Gunther Stammwitz wrote:

> Hello Tom,
>
> It is an interesting question how much traffic the box can handle.
> During normal operations I'd say that 500 Mbits/sec should be
> possible, but the even more interesting question would be how much
> PACKETS PER SECOND the box can handle

routing or accepting locally?

> ? We've got the problem that our linux-boxes are freezing

lock-ups? or applications not dealing with connections any more?

> when an
> attack with let's say only 40 megabits but hundreds of connections
> or packets per second are incoming. Maybe there's something wrong
> with our kernel and/or TCP-Settings.

if local connections, you can try increasing tcp read/write buffers,
eg, here's an excerpt from sysctl.conf on a box of mine:

# net tuning
net.core.rmem_default = 65535
net.core.rmem_max = 131071
net.core.wmem_default = 65535
net.core.wmem_max = 131071
net.ipv4.tcp_wmem = 4096 16384 131072
net.ipv4.tcp_rmem = 4096 87380 174760

For the 3 value options, they are <min> <default> <max>

NB: the above are the default values on linux i think.

Have a look at output of netstat to see what your buffer's are like
currently. To avail of the max size applications need to manually set
their buffer size, eg see the SendBufferSize parameter for apache.

> Happy easter,
> Gunther
>

regards,
--
Paul Jakma Sys Admin Alphyra
paulj@alphyra.ie
Warning: /never/ send email to spam@dishone.st or trap@dishone.st

AW: AW: Zebra Router??? [ In reply to ]

gstammw at gmx

Apr 20, 2003, 2:48 PM

Post #3 of 4 (3356 views)

Permalink

>but the even more interesting question would be how much
> PACKETS PER SECOND the box can handle

routing or accepting locally?
^^^Routing I meant.

> ? We've got the problem that our linux-boxes are freezing
lock-ups? or applications not dealing with connections any more?
^^^the system is acting as a router and it is locking up.

I can't login any more locally, I can't ssh,
The box is losing a lot of packets and so on.
The box simply stops routing.

> when an
> attack with let's say only 40 megabits but hundreds of connections or
> packets per second are incoming. Maybe there's something wrong with
> our kernel and/or TCP-Settings.

if local connections,
you can try increasing tcp read/write buffers,
eg, here's an excerpt from sysctl.conf on a box of mine:
^^^^
No.. Routing I meant.
Will this tweak help too for routing ?

This goddamn outlook can't quote - I'm sorry.

Thanks,
Gunther

Re: AW: AW: Zebra Router??? [ In reply to ]

paulj at alphyra

Apr 20, 2003, 2:54 PM

Post #4 of 4 (3325 views)

Permalink

On Sun, 20 Apr 2003, Gunther Stammwitz wrote:

> ^^^Routing I meant.

ok.

> ^^^the system is acting as a router and it is locking up.
>
> I can't login any more locally, I can't ssh, The box is losing a lot
> of packets and so on. The box simply stops routing.

but its still up? once the load subsides does it come back? and what
interfaces do you have this load through, and what are they? (and what
driver / versions of driver and what version of linux).

> Will this tweak help too for routing ?

no. its solely for increasing sizes of socket buffers.

> This goddamn outlook can't quote - I'm sorry.

Outlook can i think, though its carefully hidden in the options.
somewhere under 'compose' preferences or somesuch (is my vague
memory).

> Thanks,
> Gunther

regards,
--
Paul Jakma Sys Admin Alphyra
paulj@alphyra.ie
Warning: /never/ send email to spam@dishone.st or trap@dishone.st