Intermittent one-way packet loss - Tilted Forum Project Discussion Community

cliche · 10-27-2003, 12:33 PM

Exactly what it says on the tin

Every now and again, one of the buildings in my college (small college, one router in the main building, switches elsewhere with various media converters/laser links etc) will disconnect from the rest of the college for hours/minutes. It then goes back up for mins/hours, and repeats.

At first, I assumed that the building was disconnecting completely - during an episode I can ping computers in the same building, but not ones on the main college site. However, running a port capture recently showed me that the various broadcasts from the main site are reaching this building - but it seems packets are not going the other way.

The same hardware has been working absolutely fine for some time - the problem started this year; our computer officer is blaming a combination of WinXP and DHCP (why DHCP I completely fail to understand).

Does anyone have any ideas? I'll happily provide further info if I can... I have two 2 minute port captures, one from a period when it was working, and one when it wasn't...

Thanks!

Sty · 10-27-2003, 02:53 PM

spanning tree

cliche · 10-27-2003, 03:28 PM

I've found some entries in the logs that mention spanning tree (I know nothing about this BTW) - what should I be looking for? There are 3 MAC addresses broadcasting STP messages. The only obvious difference I can find between the two logs is that in the 'working' one, one of the MACs is sending "Conf. TC + Root" rather than "Conf. Root" Does that mean anything?

I'll have a look on google, but any other information would be gratefully received

10-27-2003, 12:33 PM	#1 (permalink)
cliche Rookie Location: Oxford, UK	Intermittent one-way packet loss Exactly what it says on the tin Every now and again, one of the buildings in my college (small college, one router in the main building, switches elsewhere with various media converters/laser links etc) will disconnect from the rest of the college for hours/minutes. It then goes back up for mins/hours, and repeats. At first, I assumed that the building was disconnecting completely - during an episode I can ping computers in the same building, but not ones on the main college site. However, running a port capture recently showed me that the various broadcasts from the main site are reaching this building - but it seems packets are not going the other way. The same hardware has been working absolutely fine for some time - the problem started this year; our computer officer is blaming a combination of WinXP and DHCP (why DHCP I completely fail to understand). Does anyone have any ideas? I'll happily provide further info if I can... I have two 2 minute port captures, one from a period when it was working, and one when it wasn't... Thanks! __________________ I can't understand why people are frightened of new ideas. I'm frightened of the old ones. -- John Cage (1912 - 1992)

10-27-2003, 02:53 PM	#2 (permalink)
Sty Patron Administrator Location: Tôkyô, Japan	spanning tree __________________ br, Sty I route, therefore you exist

10-27-2003, 03:28 PM	#3 (permalink)
cliche Rookie Location: Oxford, UK	I've found some entries in the logs that mention spanning tree (I know nothing about this BTW) - what should I be looking for? There are 3 MAC addresses broadcasting STP messages. The only obvious difference I can find between the two logs is that in the 'working' one, one of the MACs is sending "Conf. TC + Root" rather than "Conf. Root" Does that mean anything? I'll have a look on google, but any other information would be gratefully received __________________ I can't understand why people are frightened of new ideas. I'm frightened of the old ones. -- John Cage (1912 - 1992)