XDP Redirect detail

XDP Redirect detail

[Marco]

Hi

Can XDP_REDIRECT forward packets to egress interface with speed
different than ingress interface?

More precisely, if ingress interface speed is 100 Gbps and the egress
interface speed is 10 Gbps, the xdp program can be load on two
interfaces and forward traffic (using XDP_REDIRECT) between them?

Best regards

Marco

Re: XDP Redirect detail

[Toke Høiland-Jørgensen]

Marco <ctxspi@gmail.com> writes:

> Hi
>
> Can XDP_REDIRECT forward packets to egress interface with speed
> different than ingress interface?
>
> More precisely, if ingress interface speed is 100 Gbps and the egress
> interface speed is 10 Gbps, the xdp program can be load on two
> interfaces and forward traffic (using XDP_REDIRECT) between them?

Well, yes, it can forward packets just fine; but it'll just forward each
packet as it comes in, there's no mechanism for queueing or otherwise
rate limiting them. 10->100G is fine, of course, but in the other
direction, if you are receiving at 100Gbps line rate, you'll end up
forwarding 10 Gbps of it out the 10G interface and dropping the rest,
semi-randomly as the TX buffers overflow.

We're working on adding a  queueing mechanism to XDP to help with this,
but it'll probably be a little while yet before it surfaces...

-Toke

Re: XDP Redirect detail

[Marco]

Hi Toke

Your information is very useful for me.

Thanks for your reply.

Marco

Il giorno sab 16 apr 2022 alle ore 19:02 Toke Høiland-Jørgensen
<toke@redhat.com> ha scritto:
>
> Marco <ctxspi@gmail.com> writes:
>
> > Hi
> >
> > Can XDP_REDIRECT forward packets to egress interface with speed
> > different than ingress interface?
> >
> > More precisely, if ingress interface speed is 100 Gbps and the egress
> > interface speed is 10 Gbps, the xdp program can be load on two
> > interfaces and forward traffic (using XDP_REDIRECT) between them?
>
> Well, yes, it can forward packets just fine; but it'll just forward each
> packet as it comes in, there's no mechanism for queueing or otherwise
> rate limiting them. 10->100G is fine, of course, but in the other
> direction, if you are receiving at 100Gbps line rate, you'll end up
> forwarding 10 Gbps of it out the 10G interface and dropping the rest,
> semi-randomly as the TX buffers overflow.
>
> We're working on adding a  queueing mechanism to XDP to help with this,
> but it'll probably be a little while yet before it surfaces...
>
> -Toke
>


-- 
E' meglio coltivare GNU/Linux... tanto Windows si pianta da solo!!

Re: XDP Redirect detail

[Toke Høiland-Jørgensen]

Marco <ctxspi@gmail.com> writes:

> Hi Toke
>
> Your information is very useful for me.
>
> Thanks for your reply.

You're welcome! :)

-Toke