Behnam,
We are for sure zeroing in on the problem. Look at the output drops in the attached picture. You're dropping 100% of your packets!
Cisco links documentation to troubleshoot output drops here: https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/6343-queue-drops.html#anc9
From the site:
Troubleshoot Output Queue Drops
You can decrease, or even prevent, output drops if you adjust the configuration of these features:
Duplex mode—If the interface works in half-duplex mode, configure it (if possible) to work in full-duplex.
Layer 2 windowing mechanism—If x.25 encapsulation is configured on the interface, increase the x.25 window size. For more information, see Setting Default Window Sizes.
Distributed switching—On Cisco 7500 routers, if Versatile Interface Protocol (VIP) cards are installed in the chassis, enable distributed switching. When you do so, the incoming VIP buffers up to 1 second of traffic for the interface if the outgoing interface is congested. This is called rx-side buffering .
Note: Never increase the output queue in an attempt to prevent output drops. If packets stay too long in the output queue, TCP timers can expire and trigger retransmission. Retransmitted packets only congest the outgoing interface even more.
If output drops still occur after you adjust the configuration of the router as recommended, it means that you cannot prevent or decrease output drops. However, you can control them, and this can be as effective as prevention. There are two approaches to control output drops:
Congestion management
Congestion avoidance
Both approaches are based on traffic classification, and you can use them in parallel.
However, as you said that switching interfaces fixes the problem (Not sure if that fixes it permanently?) the issue is probably not congestion and could just be that the switchport has gone bad. Sadly, at this point I would refer you to the TAC desk to verify that the interface is bad and possibly get a replacement if the device is under a service contract.
I'm sorry I didn't have better news for you.
Please rate/mark answers if you find them helpful.
-Zac
