On 23 June 2017 at 08:39, Vincent Bernat <[email protected]> wrote: Hey,
> Related question: why isn't cut-through the default mode? Is there any > downside of this mode (apart from forwarding invalid frames which > shouldn't matter much nowaday)? You'll pass errored frames to the network, as you'll only know about errors after you've sent the frame. In reality this isn't such a big deal, as we don't guarantee non-brokenness of frames anyhow, generally devices, even switches, regenerate ethernet frame (because they have to, if VLAN stack, COS etc changes, so they do it always for simplicity) on egress and calculate new FCS on it, so if there is broken memory on device, we calculate correct FCS on the frame we just broke. But also upside on cut-through is very limited, you obviously only can do cut-through if egress happens to be completely empty, even in modestly loaded box, you'd often operate store-and-forward. So you have to have very specific application to see consistent cut-through behaviour. -- ++ytti _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
