我有一个带有 NM-16ESW 交换机模块的 Cisco 路由器（全是虚拟的，在 GNS3 上）。交换机连接到路由器和两台主机，有大量模拟流量通过交换机。但是，接口计数器显示零输入和输出。导致此问题的原因可能是什么？
ESW3#show int counters
Port InOctets InUcastPkts InMcastPkts InBcastPkts
Fa1/0 0 0 0 0
Fa1/1 0 0 0 0
Fa1/2 0 0 0 0
Fa1/3 0 0 0 0
Fa1/4 0 0 0 0
Fa1/5 0 0 0 0
Fa1/6 0 0 0 0
Fa1/7 0 0 0 0
Fa1/8 0 0 0 0
Fa1/9 0 0 0 0
Fa1/10 0 0 0 0
Fa1/11 0 0 0 0
Fa1/12 0 0 0 0
Fa1/13 0 0 0 0
Fa1/14 0 0 0 0
Fa1/15 0 0 0 0
Port OutOctets OutUcastPkts OutMcastPkts OutBcastPkts
Fa1/0 0 0 0 0
Fa1/1 0 0 0 0
Fa1/2 0 0 0 0
Fa1/3 0 0 0 0
Fa1/4 0 0 0 0
Fa1/5 0 0 0 0
Fa1/6 0 0 0 0
Fa1/7 0 0 0 0
Fa1/8 0 0 0 0
Fa1/9 0 0 0 0
Fa1/10 0 0 0 0
Fa1/11 0 0 0 0
Fa1/12 0 0 0 0
Fa1/13 0 0 0 0
Fa1/14 0 0 0 0
Fa1/15 0 0 0 0