Packets are dropped in hardware This section discusses how to troubleshoot problems in which loss of packets occurs in all traffic, on specific traffic flows, in specific types of traffic, consistently, or intermittently.
Ping fails If pings do not successfully traverse the device, try the following operations.
QoS configuration causes tail drops Tail-drop queueing is the most basic form of congestion control. Normal operation is first-in, first-out (FIFO) until all buffers are exhausted. After that, new frames are dropped.
SSH or Telnet operation into the device fails Assuming a correct IP address and correct login credentials, failure to access the device using SSH or Telnet could be for one of the following reasons:
Traffic is not being forwarded If the traffic is not being forwarded, you may need to examine packets in transit across links to understand the traffic pattern on a specific port.
Upgrade fails If firmware upgrade fails, troubleshooting varies if the failure was before or after device reload.