某局点S6800交换机堆叠口流量异常问题

两台68堆叠，现场将备框只保留了两个堆叠口（2/0/53,2/0/54），其他接口均没有接线。

在上述场景下，流量应该只走主框，不会存在跨框的流量，但是现场在备框上看堆叠口（2/0/53,2/0/54）入方向还有很多流量，且大部分为单播流量。

FortyGigE2/0/53

Current state: UP

IP packet frame type: Ethernet II, hardware address: 48bd-3db7-c204

Description: FortyGigE2/0/53 Interface

Bandwidth: 40000000 kbps

Loopback is not set

Media type is optical fiber, port hardware type is 40G_BASE_SR4_QSFP_PLUS

40Gbps-speed mode, full-duplex mode

Link speed type is autonegotiation, link duplex type is autonegotiation

Maximum frame length: 10000

MDI type: Automdix

Last link flapping: 12 hours 43 minutes 45 seconds

Last clearing of counters: Never

Peak input rate: 1590231184 bytes/sec, at 2020-02-10 12:18:28

 Peak output rate: 1704 bytes/sec, at 2020-02-10 13:36:06

 Last 300 second input: 2690588 packets/sec 1576604065 bytes/sec 32%

Last 300 second output: 3 packets/sec 1696 bytes/sec 0%

Input (total):  89103344918 packets, 49539409826260 bytes

         89101874521 unicasts, 12 broadcasts, 1470034 multicasts, 0 pauses

Input (normal):  89103344567 packets, - bytes

         89101874521 unicasts, 12 broadcasts, 1470034 multicasts, 0 pauses

FortyGigE2/0/54

Current state: UP

IP packet frame type: Ethernet II, hardware address: 48bd-3db7-c208

Description: FortyGigE2/0/54 Interface

Bandwidth: 40000000 kbps

Loopback is not set

Media type is optical fiber, port hardware type is 40G_BASE_SR4_QSFP_PLUS

40Gbps-speed mode, full-duplex mode

Link speed type is autonegotiation, link duplex type is autonegotiation

Maximum frame length: 10000

MDI type: Automdix

Last link flapping: 12 hours 43 minutes 45 seconds

Last clearing of counters: Never

Peak input rate: 1579865906 bytes/sec, at 2020-02-10 12:36:12

 Peak output rate: 19001 bytes/sec, at 2020-02-10 02:17:07

 Last 300 second input: 2648274 packets/sec 1522669438 bytes/sec 31%

Last 300 second output: 54 packets/sec 16319 bytes/sec 0%

Input (total):  88994865784 packets, 49473884579825 bytes

         88994409504 unicasts, 106934 broadcasts, 349032 multicasts, 0 pauses

Input (normal):  88994865470 packets, - bytes

         88994409504 unicasts, 106934 broadcasts, 349032 multicasts, 0 pauses

未知单播也会显示为单播。如果这个报文出接口是聚合，报文走未知单播的话， 会在2个槽位都发一份，然后在各槽位查non_uc_block_MASk 表决定是否能转发。所以这个流量目前看应该是未知单播的流量，如果聚合在slot 2没选中成员，会在堆叠口进来后查non_uc_block_mask 后丢掉。

现场的情况属于正常实现机制，无需关注