Clock Recovery failed on 8610 1

[arreniuse]

Hello!

I get the following error in a passport8610:

HW WARNING HwCheck: "Clock Recovery Failed Reset tmux on slot 8"

Can anyone tell me what it means?
I did not found any explanation in nortel's site and in nortel's official guide.
Thanks!

 

[anthonyanderberg]

The short answer is that its nothing to worry about if they don't happen too often and you aren't seeing any issues. I suspect that most sites see a few of these messages each year, I certainly do. I looked back in my notes and in 2004 Nortel told me that we should be concerned if there are 3 errors in 5 minutes or 10-15 errors in a 24 hour period.

The long answer requires a little background, the details of which will vary based on what version cards you have. The M, E, and 'pre-E' modules have three key ASICs: the OctaPID provides buffering/QoS and segments frames into cells, the RaptARU does address lookup/filtering, and the TapMUX is the backplane interface. As I recall the CPU/Fabric card ASICs are the FAD and SWIP, although I don't recall the exact function of each. Newer R series modules have a FPGA chip that does many of these functions and allows the folks at Nortel to add features/fixes without needing to redesign hardware.

A 'Clock Recovery' is the backplane timing being resynchronized, and in this case your slot 8 TapMUX didn't properly sync with its partner ASICs on the switch fabric. Since an out-of-sync TapMUX would mean lost data the controlling software reset the chip in an effort to fix the issue. If that's your only message then the reset worked and as long as it doesn't happen very often you can sleep well.

If the reset didn't work or if data was lost because of the issue you'd see additional messages saying that other ASICs were being reset and then you might want to open a ticket with Nortel.