Hi, On Thu, Oct 12, 2000 at 07:51:58PM +0100, Mike Hughes wrote:
On Thu, 12 Oct 2000, Christian Panigl, ACOnet/VIX/UniVie wrote:
Now it turned out, probably because "Vienna is different", that more than 90% of all (Cisco) router FastEthernet interfaces connected to the Vienna Internet eXchange have MAC addresses ending with Hex 0 !!! And nope, it's not Halloween today (for those who understand German ;-)
I wonder if it's because of the position that the FE interfaces are in people's Cisco interfaces, coupled with the way the MAC addresses are handed to the port adapter by the chassis in 7xxx boxes, that you tend to end up with Hex 0?
That's my theory as well. The Chassis has a handful of MAC addresses that are then handed out to the PAs following some algorithm, like "8 MACs per Slot" (which would be needed for OIR on PA-8E's, for example).
I've noticed that on all LINX's own 7200s, fa0/0 ends in 0, and fa1/0 ends in 8, for example. Looking at the LINX table (which Jesper has sent, so I won't waste bandwidth), I see a lot of 0's and 8's. Could it be that there are a lot of people with fa0/0 of 7200's connected to the VIX?
Definitely so at the INXS and DECIX (7200s, some 71xx's, a few 75xx's and GSRs).
We appear to have found a flaw in the Cisco load-balancing hash, which is expecting mostly end-stations (servers/workstations with NICs) with a wide spread of low bits. Of course, we then hit this with they way C7xxx boxes give out MAC addresses and it all goes wonky.
Yep. Gert Doering -- NetMaster -- SpaceNet GmbH Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299