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Discarded Frames

qwertys21
Level 1
Level 1

We have 2 core switches with a lot of gigabit uplinks to other switches. Now there have been discarded frame reports on a lot of these gigabit interfaces.

How can I accurately troubleshoot this and also to resolve this issue?

Thanks

2 Replies 2

williamsdo
Level 3
Level 3

Looks like the transmission rate overflow, when a interface is receiving packets and the quequ's are filled up the interface will start to discard packets/frames. You might start by looking at QOS read below.

Overview

Typically, networks operate on a best-effort delivery basis, which means that all traffic has equal priority and an equal chance of being delivered in a timely manner. When congestion occurs, all traffic has an equal chance of being dropped.

QoS makes network performance more predictable and bandwidth utilization more effective. QoS selects (classifies) network traffic, uses or assigns QoS labels to indicate priority, makes the packets comply with the configured resource usage limits (polices the traffic and marks the traffic), and provides congestion avoidance where resource contention exists.

PFC QoS classification, policing, marking, and congestion avoidance is implemented in hardware on the PFC, DFCs, and in LAN switching module port Application Specific Integrated Circuits (ASICs

http://www.cisco.com/en/US/customer/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/qos.html

Thanks

So how will I know which packets needs QoS?

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