V7平台的AP降级到V5平台，能获取到地址，但注册不上的经验案例

某局点目前的控制器型号为WX3024E，版本为version 5.20, Release 3509P58

新添加了一批V7降级V5的AP,做完配置之后AP都注册不上，能够获取地址，能够ping通AC,所有的AP的状态目前均为I.

 AP Name                          State Model            Serial-ID

-------------------------------------------------------------------------------------------------------

 2-12f-01              I     WA4320i-ACN      210235A1GQC16B001528

 2-12f-02              I     WA4320i-ACN      210235A1GPC16B000278

 2-12f-03              I     WA4320-ACN-SI    219801A0T7816CE05662

分别在AC上面开启debugging wlan lwapp 和console口登陆到AP上，输出信息如下：

APconsole口注册的的相关信息：

DHCP server&＃39;s IP address is 172.16.100.1

Client&＃39;s assigned address is 172.16.100.3           获取IP地址

DNS domain name got from DHCP server is

DNS server&＃39;s IP address is 0.0.0.0

Default Gateway&＃39;s IP address is 172.16.100.1

This client&＃39;s subnet mask is 255.255.255.0

The length of option 43 is: 0

 Change State : Idle to Broadcast Discovery    Idle变为广播Discovery

 Change State : Broadcast Discovery to Join    广播Discovery变为Join

Change State : Join to JoinAck                Join变为JoinAck 

 Change State : JoinCfm to Image Download..........................................................

..............................................  JoinCfm变为Image

 [State : ImageLoad] Image download successful   下载镜像文件

 [State : Idle] Reset request, rebooting the AP   镜像下载完成后重启

Rebooting......

看起来AP设备注册的过程很正常，没有明显异常问题,重启完成之后，AP也可以ping通AC的地址，表示路径也没有问题

<WA4320i-ACN>ping 172.16.100.1               //可以正常ping通AC的地址，说明数据可达AC

  PING 172.16.100.1: 56  data bytes, press CTRL_C to break

    Reply from 172.16.100.1: bytes=56 Sequence=0 ttl=255 time=1 ms

    Reply from 172.16.100.1: bytes=56 Sequence=1 ttl=255 time=1 ms

    Reply from 172.16.100.1: bytes=56 Sequence=2 ttl=255 time=1 ms

    Reply from 172.16.100.1: bytes=56 Sequence=3 ttl=255 time=1 ms

    Reply from 172.16.100.1: bytes=56 Sequence=4 ttl=255 time=1 ms

  --- 172.16.100.1 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

round-trip min/avg/max = 1/1/1 ms

AC上输出信息：

*Mar  7 22:17:27:039 2017 H3C LWPS/7/Pkt_Rcvd: 

Received Discovery Request from 172.16.100.3 (Length: 174)(to 255.255.255.255)   //收到来自AP的Discovery Request请求报文

04 00 00 a8 00 00 01 01 00 a0 00 00 00 00 3a 00

………………………….

*Mar  7 22:17:27:109 2017 H3C LWPS/7/Event:  Discovery request message received from AP with WA4320i-ACN Model and Serial-ID 210235A1GPC16B000278 and IP [172.16.100.3] and SoftVer [279075200].

*Mar  7 22:17:27:129 2017 H3C LWPS/7/Error:  SUB AP: Failed to get Node, not found [B0F9-6388-1620].

*Mar  7 22:17:27:139 2017 H3C LWPS/7/Event:  Success get software version [279075200].

*Mar  7 22:17:27:150 2017 H3C LWPS/7/Event:  Get software version extend info [0].

*Mar  7 22:17:27:160 2017 H3C LWPS/7/Error:  Failed to connect to AC for AP 2-12f-02 [Serial-ID 210235A1GPC16B000278][MAC:b0f9-6388-1620].

*Mar  7 22:17:27:180 2017 H3C LWPS/7/Error:  Discovery Request is dropped due to Unknown failure

//发送请求回访报文丢弃因为未知的错误

*Mar  7 22:17:33:688 2017 H3C LWPS/7/Pkt_Rcvd: 

Received CAPWAP Discovery Request from 172.16.100.3 (Length: 192)(to 255.255.255.255)

 00 10 02 00 00 00 00 00 00 00 00 01 01 00 b3 00

//这里的报文有点奇怪了，为什么要会收到capwap的Discovery Request 报文呢，正常的话是采用LWAPP协议进行注册的

 *Mar  7 22:17:33:930 2017 H3C LWPS/7/Pkt_Send: 

Sent CAPWAP Discovery Response to 172.16.100.3 (Length: 99)(from 172.16.100.1)

 00 10 02 00 00 00 00 00 00 00 00 02 01 00 56 00

…………

// AC给AP回应了CAPWAPP请求的Discovery Response 报文

这个地方怀疑是否因为AC开启了capwap协议导致，后面跟代理商了解了这批AP原来的版本为V7版本，后续通过AC切换为V5版本的，但是没有将AC的隧道注册方式修改过来。

隐藏视图开启lwapp的功能

[AC-hidecmd]fpl-diag enable

[AC-hidecmd]fpl-diag drv_capwap_set 0

Set capwap flag to close success!   //提示关闭capwap成功

修改之后重启AC设备后，相应的AP都注册上，问题解决。

1.如果所有的AP注册不成功，按照常规的排查方式没有问题的情况下，而且最近有从V7版本切换为V5版本的AP的情况，建议检查AC是否关闭了lwapp的功能。

2.除了隐藏视图开启lwapp的方法，还可以AP模板配置tunnel compliance draft开启隧道注册为lwapp模式。

3.切换隧道注册协议命令的时候一定要注意，需要重启设备才能生效。