[j-nsp] Strange Link down problems on M-series

[Joerg Staedele]

Hi,

i currently don't have any more ideas on a really strange problem:

Router A is connected to Router B via a Colt Gigabit-Ethernet Link. The Link is on a dark fiber and only two ADVA converters are installed. The link was working for nearly two years now and suddenly we have big problems.

Router A and Router B tell that the link goes down very often, but only for some msecs (I checked that with setting hold-time down 1000 and the problem was "gone").

We already moved the link from Router B to Router C (same location) and the problem was still there, so Router B seems to be ok.

Then we moved the link from Router A to Switch A (same location) and then Router B told us again that the link is down but the Switch (in this case a Cisco 3550) didn’t show anything in the log (no interface down, crc errors etc.).

We also connected the link on another interface on Router A but the problem persists.

If I look on the ge-pic in the Junipers, I see that there are many interrupts ("Normal interrupts are enabled, total count is 5412")

Colt already replaced their Converters and checked the link and they say everything is fine ... but it is not, at least not for our Juniper Routers.

Anyone has an idea or hint what else we can try?

Best regards and thanks,

 Joerg