Current state of FreeBSD routing

[Julian Elischer]

On 2/1/11 10:10 PM, Eugene Grosbein wrote:
> On 02.02.2011 05:11, Markus Oestreicher wrote:
>
>> 2) Fastforwarding vs multiple netisr:
>> In the past (6.x) using fastforwarding=1 was the best option for dedicated routers.
>> I found "multiple netisr" added to 8.0. Can that help with routing on multiple cores?
> Yes, it allows more even distribution of input traffic processing over cores.
>
>> Any experience from using it in production?
> It helps greatly but I was forced to disable it for mpd-based router
> where there are many dynamically born/destroyed network interfaces.
>
> I suspect it increases possibility of kernel panic in such configuration
> due to famous 'dangling pointer' problem: an interface ngXXX got destroyed
> while packets received from it reside in netisr queues. Then kernel might
> panic while processing these packets if needs to check incoming interface,
> f.e. due to ipfw antispoofing rules.

workaround for that may be to delay ng interface destruction by 2 
seconds or something.

I'll think about it..

>> 3) lagg:
>> I found lagg(4) mostly mentioned on home user setups.
>> Any experience with using lagg in high-pps environments? (>100k pps)
> Works fine for me.
>
>> Will lagg play nicely together with multiple netisr routing or fastforwarding?
>> How much overhead will it add versus a single connection?
> Unnoticed.
>
> Eugene Grosbein
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