Messages in this thread | | | From | "H. Peter Anvin" <> | Subject | Re: Ethernet NIC dual homing | Date | 29 Oct 2001 19:15:39 -0800 |
| |
Followup to: <p05100304b803c6908755@[10.128.7.49]> By author: Jonathan Lundell <jlundell@pobox.com> In newsgroup: linux.dev.kernel > > > >It doesn't work to detect link state through bridging device (say, bridged > >ethernet over T3). The T3 might go down, but your MII link to the local > >router will remain "up", so you will never know about the loss of link and > >your packets will happily go into the void... > > ARP isn't going to do much for you once the failure is beyond the > local segment, is it? >
ARP is broadcast to the layer 2 local segment; link detection refers to the layer 1 local segment, which is not necessarily the same.
On the other hand, doing link detection is extremely useful for a portable computer: when I plug in my Ethernet cable in a portable system I want it to try to start doing DHCP detection and anything else that is normally associated with the interface being "up" at that time.
-hpa -- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |