Re: [babel] [Babel-users] rather than ripemd160...

[Dave Taht <[e-mail]>]

Dave Taht <[e-mail]> writes:

> Juliusz Chroboczek <[e-mail]> writes:
>
>>> Why not? If it's not MTI you risk the case where you get to pick between
>>> "good performance on weak devices" and "interoperability with RFC-only
>>> implementations".
>>
>> Is there any evidence that there are devices that can reasonably run Babel
>> and that are too weak to use SHA256 for protecting control traffic?
>>
>> I don't have an ARM device handy right now, but a 450MHz MIPS 24Kc is able
>> to SHA256 on the order of 16MB/s.  That's 10000 full-size frames per second,
>> or on the order of 600000 Babel updates per second.

I've been meaning to poke into this a while:

https://code.fb.com/connectivity/open-r-open-routing-for-modern-networks/

But I do take your point. It would be good to know that on a given
10,000 route 200 router babel network that hashing overhead accounted
for .0X% of the 100% of cpu in use.

You are reasonable to assume that sha256 would be low overhead relative
to other factors, I think. Still, would like to go measure.

Aside: Where does the 300ms figure for re-attempting a challenge and
response come from?