I have a fiber connection from my ISP which terminates in a Cisco 897 VAMW. It has been running fine for several month, but recently we started getting very high packet loss (60%) when traffic hits 20Mbps.
Our ISP checked the fiber and it was without errors - so they replaced the Cisco 897 VAMW with a new one - and it has been running fine for nearly 1 week now, but last night we started seeing packet loss again.
2 routers with the same error, i find unlikely. I rather suspect it could be related to a heating issues on the site. Reading the specs for Cisco 897, it operates a 0 to 40 celcius - and i suspect, it could reach higher temps inside after some days. Is the 897 router very sensitive to high temps?
A have a 2960T switch and a Watchguard XTM25 unit installed at the same location right next to the 897 router - and they work without issues.
there is always a possibility for bad venting or high temperatures to cause packets loss, however, you can only see that from the output I requested. I would suggest to ask your ISP to look at that output...