3. No symptom of egress or ingress congestion is found on a switchport: Find the devices in communication with this switchport and continue investigation there to find symptoms of egress or ingress congestion (Figure 4-4). This takes to (1) or (2) above. 查找与该交换端口通信的设备，并继续调查，以发现出口或入口拥塞的症状（图 4-4）。这与上述 (1) 或 (2) 的情况类似。

The following subsections explain these scenarios in detail. 以下各小节将详细解释这些情况。

Egress Congestion Symptoms on a Switchport

Symptoms of egress congestion on a switchport indicate that this port is in the congestion path. These symptoms can be credit-loss, timeout-drops, TxWait, or high egress utilization (Tx-datarate). 交换端口上的出口拥塞症状表明该端口处于拥塞路径中。这些症状可能是信元损失、超时掉线、TxWait 或高出口利用率（Tx-datarate）。

In Figure 4-5, egress congestion symptoms are found on edge switchport 1. Being an edge port, switchport 1 is directly connected to the culprit end device. 在图 4-5 中，边缘交换端口 1 出现了出口拥塞症状。作为边缘端口，交换端口 1 直接连接到造成拥塞的终端设备。

Egress congestion symptoms can also be found on core switchports, such as switchport b in Figure 4-6. In these cases, fo