Re: strong vs weak host

Hi,

On Thu, Feb 21, 2019 at 01:19:57PM -0800, Mike Wright wrote:
> I followed "Using netem on one..." with interest and want to thank
> the participants.  I'd never come across those terms (strong host,
> weak host, arp flux) before.  Researching them broadened my
> networking understanding tremendously.
> 
> The following link hit all the bases in your discussion:
> https://unix.stackexchange.com/questions/258810/
> linux-source-routing-strong-end-system-model-strong-host-model
> ?answertab=votes#tab-top

Thanks for the link.

> My question has to do with cost between the models where cost refers
> to time to route.  Since the strong model seems to involve a lot
> more decision making is there an appreciable difference in the time
> spent routing versus the weak model or is the difference so small as
> to be inconsequential?

I would not expect that the choice of strong or weak model to have an
effect on "routing" performance. Simple checks suffice for the strong ES
model: discard if ingress interface IP is different from destination IP,
outgoing interface is that with the same IP as the packet to send. I
would not expect significant difference in performance, and the strong
ES model might even help performance a tiny bit.

If one thinks about a gateway with dedicated forwarding hardware using
TCAM, e.g. a switch, checking if a packet is allowed to ingress or egress
an interface has no impact on forwarding performance.

Thanks,
Erik
-- 
The Linux approach is to do the job right. [...] This is the Linux way
of doing things. It's like the GPL and being shouted at by Linus. They
are things you accept when you choose to take part.
                        -- Alan Cox