The AP version is slow to be released

AC——Core Switch——Access Switch——AP

Version download (pre-download) is very slow, over an hour for 50 APs. Normal concurrency of 200+ can be downloaded in 2 minutes.

AP version is slow to download, the first thing to consider is the link problem.

1. Check the statistics of CAPWAP messages, clear the count of CAPWAP messages on AC and AP at the same time before turning on the version download, and then turn on the download and compare the statistics of the number of messages on both sides, especially the number of Image Date Request/Response messages. By comparing, we can find that some Image Date Request/Response messages are lost on the intermediate link.

Command:

[WX1840H-probe]display/reset system internal wlan ap mac-address xxxx-xxxx-xxxx capwap packet-statistics
[AP-probe]display/reset system internal wlan ap all capwap packet-statistics 

2. Ordinary ping packets cannot prove the stability of the CAPWAP tunnel. The quality of the link between the AC and the AP can be checked by ap-link-test, focusing on UDP large packet throughput. (The command ap-link-test should be used with caution, as some versions of some ACs may cause the device to reboot abnormally.)

Command:

[office-probe]wlan ap-link-test xxx.xxx.xxx.xxx packet-length 1500 source 5246 destination 5246 continuous rate 100 time 10 
Transmitted packets : 1000 
Received packets : 1000 Packet loss : 0.00% 
Transmitted packet length : 1500 
Received packet Length : 1500 
Out-of-order packets : 0 
Min RTT(ms) : 0 
Average RTT(ms) : 0 
Max RTT(ms) : 13 

3. Based on either of the above two means can determine that the message is lost on the intermediate link, the next step is to determine which device it is specifically lost on. Through the flow system can be judged, find a stable reproduction of the AP, write two UDP 5246 port-based ACL application under the interface. (5246 is the control port and 5247 is the data port)

Command:

 #
 acl advanced 3001
 rule 1 permit udp source 10.xxx.xxx.254 0 destination 10. xxx.xxx.24 0 source-port eq 5246 
rule 2 permit udp source 10.xxx.xxx .24 0 destination 10.xxx.xxx.254 0 destination-port eq 5246 
 #

4. The result of the Qos test shows that the message is lost on the core switch. Further investigation is that there is a wireless feature pack installed on the Core switch, which causes the passing CAPWAP message to be sent to the CPU and no longer forwarded to the AC.

Uninstall the wireless feature pack on the Core switch.