Re: Internet Traffic load balancing

:)
BTW, just after shutting down everything, I stared at one of the posts
and it became evident that I forgot to clear one thing out: does it
also work for local traffic ?

Well, it granted a test :)
It does, it works too, and the hash is different!

And the hash is also different depending on the originating host.
So it seems origin enters the hashing to.

Done with this for the time being...
-Carlos

Marko Milivojevic @ 03/05/2011 13:18 -0300 dixit:
> This is one of the most amazing threads on Group Study in a long while
> :-). I just had to say it!
>
> --
> Marko Milivojevic - CCIE #18427
> Senior Technical Instructor - IPexpert
>
> FREE CCIE training: http://bit.ly/vLecture
>
> Mailto: markom_at_ipexpert.com
> Telephone: +1.810.326.1444
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> On Tue, May 3, 2011 at 09:16, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:
>> Marko,
>> I made a small test and the thing makes for a lot of fun (and food for
>> thought for a R/S expert :)
>>
>> I have one generator (ostinato), sending steady traffic to 10 different
>> addresses, 1.1.1.1 .. 10.10.10.10 (@1000 pps) to a router R1 which has
>> 2 serials connected to router R2 acting as a sink.
>> (Actually sending pings, so the sink is answering back)
>>
>> Serial links are 20.1.1.0/30 and 20.2.2.0/30, generated 10 statics to
>> 0.0.0.0/0 via 169.254.1.1 .. 7 and 169.254.2.1 .. 3, and respective
>> recursive routes to s0/0 and s0/1.
>>
>> SNMP in R1 shows more or less balanced traffic :(
>> Hmm, I got 2 routes out (so ended with 8:1) and all traffic went to one
>> interface! What ? Added a second route and I got a 5:2 relation.
>> Aha. The 10 different destinations are not getting into 10 different
>> CEF hash buckets!
>>
>> R1 is a 2610XM running 12.4.9T7.
>> I played with "ip cef load-sharing algorithm" and the load changes.
>>
>> So my readings:
>>
>> works ? yes. (unequal load balancing using CEF, seeded by statics)
>> is obvious how ? Not at all.
>>
>> This version does not has 16 fixed buckets as Ivan documents:
>>
>> R1#sh ip cef 0.0.0.0 0.0.0.0 internal
>> *Jul B 1 12:30:36.866: %SYS-5-CONFIG_I: Configured from console by console
>> 0.0.0.0/0, version 50, epoch 0, per-destination sharing
>> 0 packets, 0 bytes
>> B via 169.254.2.2, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.2.2.2, Serial0/1 via 169.254.2.2/32
>> B B valid adjacency
>> B via 169.254.2.1, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.2.2.2, Serial0/1 via 169.254.2.1/32
>> B B valid adjacency
>> B via 169.254.1.7, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.7/32
>> B B valid adjacency
>> B via 169.254.1.6, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.6/32
>> B B valid adjacency
>> B via 169.254.1.5, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.5/32
>> B B valid adjacency
>> B via 169.254.1.4, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.4/32
>> B B valid adjacency
>> B via 169.254.1.3, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.3/32
>> B B valid adjacency
>> B via 169.254.1.2, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.2/32
>> B B valid adjacency
>> B via 169.254.1.1, 0 dependencies, recursive
>> B B traffic share 1
>> B B next hop 20.1.1.2, Serial0/0 via 169.254.1.1/32
>> B B valid adjacency
>>
>> B 0 packets, 0 bytes switched through the prefix
>> B tmstats: external 0 packets, 0 bytes
>> B B B B B internal 0 packets, 0 bytes
>> B Load distribution: 0 1 2 3 4 5 6 7 8 (refcount 1)
>>
>> B Hash B OK B Interface B B B B B B B B Address B B B B Packets
>> B 1 B B Y B Serial0/1 B B B B B B B B point2point B B B B B 0
>> B 2 B B Y B Serial0/1 B B B B B B B B point2point B B B B B 0
>> B 3 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B 4 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B 5 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B 6 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B 7 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B 8 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B 9 B B Y B Serial0/0 B B B B B B B B point2point B B B B B 0
>> B refcount 4318, covered prefixes:
>> B B 169.254.2.3/32
>> B B 169.254.2.2/32
>> B B 169.254.2.1/32
>> B B 169.254.1.7/32
>> B B 169.254.1.6/32
>> B B 169.254.1.5/32
>> B B 169.254.1.4/32
>> B B 169.254.1.3/32
>> B B 169.254.1.2/32
>> B B 169.254.1.1/32
>> B B 172.30.0.0/16
>> B B 20.2.2.0/30
>> B B 20.1.1.0/30
>> B B 224.0.0.0/4
>> B B 255.255.255.255/32
>> B B 0.0.0.0/32
>> R1#
>>
>> -Carlos
>>
>>
>>
>> Marko Milivojevic @ 02/05/2011 22:39 -0300 dixit:
>>> On Mon, May 2, 2011 at 17:45, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:
>>>> This was generated from the switching point ? I.e. it was generated by
>>>> the
>>>> router having the 5:2 statics ?
>>>>
>>>> I would test it from a neighbour, so CEF is used for sure. Local trafic
>>>> is process switched most probably.
>>> Those are valid points, but are contrary to what was originally
>>> expected. My argument was that CEF would break this, but I honestly
>>> expected that it would work when process-switched. It doesn't seem to.
>>> I will add 3rd router behind R2 and re-run the test.
>>>
>>> --
>>> Marko Milivojevic - CCIE #18427
>>> Senior Technical Instructor - IPexpert
>>>
>>> FREE CCIE training: http://bit.ly/vLecture
>>>
>>> Mailto: markom_at_ipexpert.com
>>> Telephone: +1.810.326.1444
>>> Web: http://www.ipexpert.com/
>>>
>>>
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>>>
>> --
>> Carlos G Mendioroz B <tron_at_huapi.ba.ar> B LW7 EQI B Argentina
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net