运行 OS9 固件的 S 系列交换机出现 Dell Networking 间歇性高 ICMP 延迟

尝试执行从客户端设备到网关（通常是 VLAN 接口的 IP）的 ICMP ping 时，会出现有关高延迟的间歇性问题。即使直接连接到几乎没有生产流量的网关交换机，此问题仍然会出现。一些客户担心，这反映了对正常生产流量的影响。
运行 OS9 固件的所有 S 系列平台都出现此问题。

ICMP 测试的测试场景（无生产流量）

拓扑配置

PC1: 192.168.10.100/24, Gateway: 192.168.10.1/24, VLAN10
PC2: 192.168.10.200/24, Gateway: 192.168.10.1/24, VLAN10
或
PC2: 192.168.20.200/24, Gateway: 192.168.20.1/24, VLAN20

PC1 ping交换机网关（直连）测试1-6;无论拓扑如何，都会看到相同的结果

Pinging 192.168.10.1 with 32 bytes of data:
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time=5ms TTL=255
Reply from 192.168.10.1: bytes=32 time=47ms TTL=255  <------ high latency !
Reply from 192.168.10.1: bytes=32 time=5ms TTL=255
Reply from 192.168.10.1: bytes=32 time=5ms TTL=255
Reply from 192.168.10.1: bytes=32 time=1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time=32ms TTL=255  <------ high latency !
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time=6ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time=40ms TTL=255  <------ high latency !
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
Reply from 192.168.10.1: bytes=32 time<1ms TTL=255
……
>>> (truncated)

Ping statistics for 192.168.10.1:
    Packets: Sent = 8280，Received = 8280，Lost = 0 (0% Loss)
Approximate round trip times in milli-seconds:
    Minimum = 0ms，Maximum = 55ms，Average = 1ms

两台 PC 之间的 Ping、传输流量（第 2 层，在相同和不同的 VLAN 中）（测试 1-3）

Pinging 192.168.10.200 with 32 bytes of data:
Reply from 192.168.10.200: bytes=32 time=1ms TTL=128
Reply from 192.168.10.200: bytes=32 time=1ms TTL=128
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
Reply from 192.168.10.200: bytes=32 time=1ms TTL=128
Reply from 192.168.10.200: bytes=32 time=1ms TTL=128
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
……
>>> (truncated),
……
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
Reply from 192.168.10.200: bytes=32 time<1ms TTL=128
Reply from 192.168.10.200: bytes=32 time=1ms TTL=128

Ping statistics for 192.168.10.200:
    Packets: Sent = 1233，Received = 1233，Lost = 0 (0% Loss)
Approximate round trip times in milli-seconds:
    Minimum = 0ms，Maximum = 2ms，Average = 0ms

两台 PC 之间的 Ping、传输流量（第 3 层，在两个 VLAN 中）（测试 4-6）

Pinging 192.168.20.200 with 32 bytes of data:
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
……
>>> (truncated),
……
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127
Reply from 192.168.20.200: bytes=32 time<1ms TTL=127
Reply from 192.168.20.200: bytes=32 time=1ms TTL=127

Ping statistics for 192.168.20.200:
    Packets: Sent = 808，Received = 808，Lost = 0 (0% Loss)
Approximate round trip times in milli-seconds:
    Minimum = 0ms，Maximum = 2ms，Average = 0ms

结果说明

我们已与戴尔工程部门确认，这是 CPU 调度和排队导致的正常且在意料之中的行为。

ICMP 测试应仅用作测试可达性的一种手段，而不是由于此行为导致的延迟或丢失。ICMP 流量延迟并不反映对正常生产流量的影响。CPU 繁忙也会加剧此行为 — 这适用于处于全面生产状态且流量较高的交换机。