#### client device is 192.168.8.16 - MAC address of client is 74:5c:9f:f5:a1:18 #### user moves from ap1 on sw5 to ap2 on switch6 #### now communication is lost. Client-device is not pingable: switch5#ping 192.168.8.16 Pinging 192.168.8.16 with 18 bytes of data: PING: no reply from 192.168.8.16 PING: timeout PING: no reply from 192.168.8.16 PING: timeout PING: no reply from 192.168.8.16 PING: timeout PING: no reply from 192.168.8.16 PING: timeout ----192.168.8.16 PING Statistics---- 4 packets transmitted, 0 packets received, 100% packet loss switch5#show mac address-table vlan 8 Flags: I - Internal usage VLAN Aging time is 300 sec Vlan Mac Address Port Type ------------ --------------------- ---------- ---------- 8 00:11:32:94:17:df Po3 dynamic 8 0a:1f:d4:04:d6:97 Po3 dynamic 8 10:dd:b1:c1:de:ac gi3 dynamic 8 18:3d:a2:45:4e:f4 Po2 dynamic 8 40:9f:38:69:d2:bf Po2 dynamic 8 58:38:79:18:6c:b6 Po3 dynamic 8 58:38:79:18:6d:99 Po3 dynamic 8 58:38:79:1d:5d:c8 Po3 dynamic 8 58:38:79:20:aa:0a Po3 dynamic 8 68:b5:99:a7:df:35 Po1 dynamic 8 74:5c:9f:f5:a1:18 Po2 dynamic 8 78:7b:8a:c5:a5:73 Po1 dynamic 8 90:6c:ac:a7:c7:cd Po3 dynamic 8 98:4b:e1:7e:1c:08 gi4 dynamic 8 d0:d7:83:c2:7c:a7 Po2 dynamic 8 d8:fc:93:2d:85:43 Po2 dynamic switch5#show arp Total number of entries: 4 VLAN Interface IP address HW address status --------------------- --------------- ------------------- --------------- vlan 8 Po2 192.168.8.28 d8:fc:93:2d:85:43 dynamic vlan 8 Po2 192.168.8.29 18:3d:a2:45:4e:f4 dynamic vlan 8 gi4 192.168.8.41 98:4b:e1:7e:1c:08 dynamic vlan 99 Po3 192.168.99.1 90:6c:ac:a7:c7:cd dynamic #### also no arp entry for this IP in switch5. #### Now we issue the clear on sw5: switch5#clear mac address-table dynamic interface Po2 switch5#ping 192.168.8.16 Pinging 192.168.8.16 with 18 bytes of data: 18 bytes from 192.168.8.16: icmp_seq=1. time=0 ms 18 bytes from 192.168.8.16: icmp_seq=2. time=0 ms 18 bytes from 192.168.8.16: icmp_seq=3. time=10 ms 18 bytes from 192.168.8.16: icmp_seq=4. time=0 ms ----192.168.8.16 PING Statistics---- 4 packets transmitted, 4 packets received, 0% packet loss round-trip (ms) min/avg/max = 0/2/10 #### Immediately the ping works. switch5#show arp Total number of entries: 5 VLAN Interface IP address HW address status --------------------- --------------- ------------------- --------------- vlan 8 Po2 192.168.8.16 74:5c:9f:f5:a1:18 dynamic vlan 8 Po2 192.168.8.28 d8:fc:93:2d:85:43 dynamic vlan 8 Po2 192.168.8.29 18:3d:a2:45:4e:f4 dynamic vlan 8 gi4 192.168.8.41 98:4b:e1:7e:1c:08 dynamic vlan 99 Po3 192.168.99.1 90:6c:ac:a7:c7:cd dynamic switch5#show mac address-table vlan 8 Flags: I - Internal usage VLAN Aging time is 300 sec Vlan Mac Address Port Type ------------ --------------------- ---------- ---------- 8 00:11:32:94:17:df Po3 dynamic 8 0a:1f:d4:04:d6:97 Po3 dynamic 8 10:dd:b1:c1:de:ac gi3 dynamic 8 18:3d:a2:45:4e:f4 Po2 dynamic 8 40:9f:38:69:d2:bf Po2 dynamic 8 58:38:79:18:6c:b6 Po3 dynamic 8 58:38:79:18:6d:99 Po3 dynamic 8 58:38:79:1d:5d:c8 Po3 dynamic 8 58:38:79:20:aa:0a Po3 dynamic 8 68:b5:99:a7:df:35 Po1 dynamic 8 74:5c:9f:f5:a1:18 Po2 dynamic 8 78:7b:8a:c5:a5:73 Po1 dynamic 8 90:6c:ac:a7:c7:cd Po3 dynamic 8 98:4b:e1:7e:1c:08 gi4 dynamic 8 d0:d7:83:c2:7c:a7 Po2 dynamic 8 d8:fc:93:2d:85:43 Po2 dynamic switch5# #### Not a very special config. Just simple lacp port channel: switch5#show interfaces configuration Po2 Flow Admin Ch Type Speed Neg control State -------- ------- ----- -------- ------- ----- Po2 1G 1000 Enabled Auto Up switch5#show interfaces configuration Ge2730-Aug-2019 18:25:22 %AAA-I-CONNECT: New http connection for user jpadmin, source 192.168.8.28 destination 192.168.8.5 ACCEPTED switch5#show interfaces configuration GE27 Flow Admin Back Mdix Port Type Duplex Speed Neg control State Pressure Mode -------- ------------ ------ ----- -------- ------- ----- -------- ---- gi27 1G-Fiber Full 1000 Disabled Off Up Disabled Auto switch5#show interfaces configuration GE28 Flow Admin Back Mdix Port Type Duplex Speed Neg control State Pressure Mode -------- ------------ ------ ----- -------- ------- ----- -------- ---- gi28 1G-Fiber Full 1000 Disabled Off Up Disabled Auto switch5#show lacp port-channel Po2 % Wrong number of parameters or invalid range, size or characters entered switch5#show lacp port-channel 2 Port-Channel Po2 Port Type Gigabit Ethernet Attached Lag id: Actor System Priority:1 MAC Address: 00:8e:73:2a:5a:2e Admin Key: 1001 Oper Key: 1001 Partner System Priority:1 MAC Address: 00:8e:73:1c:ce:49 Oper Key: 1001 switch5#