[LARTC] Hardware Requirements for qdisc htb/sfq

[LARTC] Hardware Requirements for qdisc htb/sfq

[Shane McKinley]

I am planning to replace our cisco 7200 core router with Linux. We
currently serve around 1500 (3/4 DSL - different router) customers with
probably half of them being concurrent at any given time.

We have a fiber network and customers currently aren't managed as far as
how much bandwidth they can use at anytime. Therefore I have constructed
a working tc qdisc Linux router as a test. It is working beautifully.

My question is what are the general hardware requirements for routing to
about 20 subnets (class c), traffic shaping for about 50 fiber customers
(TC QDISC), 2 T1s (straight into the Linux router) and about 35MB of
traffic out to the next ISP? We are planning to implement BGP sometime
in the near future.

I have been searching everywhere for some kind of guidelines, but I see
none. If anyone could give me a round about answer that would point me
in the right direction I would be obliged.

This is what I have been looking at:

2.0GHz Dual-Core Xeon, 4GB 667MGz RAM, 2x1Gbit Network Interfaces.

Is this overkill?

Thanks,

Shane McKinley

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Re: [LARTC] Hardware Requirements for qdisc htb/sfq

[Marek Kierdelewicz]

>My question is what are the general hardware requirements for routing
>to about 20 subnets (class c), traffic shaping for about 50 fiber
>customers (TC QDISC), 2 T1s (straight into the Linux router) and about
>35MB of traffic out to the next ISP? We are planning to implement BGP
>sometime in the near future.

From my experience router load is mostly dependant on pps (packet per
second).

I was doing statefull 550k pps on Athlon64 X2 5200
cpu usage was ~50% per core.

I'm doing stateless > 1m pps on Quad-core Xeon(R) CPU E5345 @ 2.33GHz,
peak cpu usage is less then 25% per core 

both configs used e1000 nics, 1GB Ram
both boxes were running BGP

>I have been searching everywhere for some kind of guidelines, but I see
>none. If anyone could give me a round about answer that would point me
>in the right direction I would be obliged.

Use irqbalance of smp affinity to distribute irqs between cores. Make
your router stateless or optimeze netfilter settings related to
conntrack (more memory, bigger hashtables ect)

>2.0GHz Dual-Core Xeon, 4GB 667MGz RAM, 2x1Gbit Network Interfaces.

Quite a lot of ram for statefull firewall + BGP (1GB would probably
suffice). As for CPU diagnose your network and compare your pps with the
numbers and platforms I specified.

cheers,
Marek Kierdelewicz
KoBa ISP
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RE: [LARTC] Hardware Requirements for qdisc htb/sfq

[Shane McKinley]

This is what I am getting atm:

5 minute input rate 21323000 bits/sec, 3544 packets/sec
5 minute output rate 7870000 bits/sec, 3084 packets/sec

So I should prolly be good with the hardware listed, huh? I am mostly
concerned about the qdisc stuff, is it more CPU intensive or RAM?

 

-----Original Message-----
From: Marek Kierdelewicz [mailto:marek@piasta.pl] 
Sent: Wednesday, November 14, 2007 4:36 PM
To: lartc@mailman.ds9a.nl
Subject: Re: [LARTC] Hardware Requirements for qdisc htb/sfq

>My question is what are the general hardware requirements for routing 
>to about 20 subnets (class c), traffic shaping for about 50 fiber 
>customers (TC QDISC), 2 T1s (straight into the Linux router) and about 
>35MB of traffic out to the next ISP? We are planning to implement BGP 
>sometime in the near future.

From my experience router load is mostly dependant on pps (packet per
second).

I was doing statefull 550k pps on Athlon64 X2 5200 cpu usage was ~50%
per core.

I'm doing stateless > 1m pps on Quad-core Xeon(R) CPU E5345 @ 2.33GHz,
peak cpu usage is less then 25% per core 

both configs used e1000 nics, 1GB Ram
both boxes were running BGP

>I have been searching everywhere for some kind of guidelines, but I see

>none. If anyone could give me a round about answer that would point me 
>in the right direction I would be obliged.

Use irqbalance of smp affinity to distribute irqs between cores. Make
your router stateless or optimeze netfilter settings related to
conntrack (more memory, bigger hashtables ect)

>2.0GHz Dual-Core Xeon, 4GB 667MGz RAM, 2x1Gbit Network Interfaces.

Quite a lot of ram for statefull firewall + BGP (1GB would probably
suffice). As for CPU diagnose your network and compare your pps with the
numbers and platforms I specified.

cheers,
Marek Kierdelewicz
KoBa ISP
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Re: [LARTC] Hardware Requirements for qdisc htb/sfq

[Marek Kierdelewicz]

>So I should prolly be good with the hardware listed, huh? I am mostly
>concerned about the qdisc stuff, is it more CPU intensive or RAM?

Shaping is not RAM hogging at all. With simpler setups It should not be
too CPU intensive either. If you plan to do per-user shaping then
consider using hashing u32 filters.
 
cheers,
Marek Kierdelewicz
KoBa ISP
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Re: [LARTC] Hardware Requirements for qdisc htb/sfq

[Mohan Sundaram]

Shane McKinley wrote:
> I have been searching everywhere for some kind of guidelines, but I see
> none. If anyone could give me a round about answer that would point me
> in the right direction I would be obliged.
> 
> This is what I have been looking at:
> 
> 2.0GHz Dual-Core Xeon, 4GB 667MGz RAM, 2x1Gbit Network Interfaces.
> 
> Is this overkill?
> 
Speed normally seen in PPS. The 7200 routes approx 1M PPS. I ran our own 
routing and classification s/w on a AMD Opteron 2Ghz, 1GB RAM and got 
1.1M PPS. Linux Kernel gave approx 700K PPS.

IMHO your h/w is way oversized but why not? H/w is cheap nowadays.

Mohan
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