ubuntu 18.04 通过 4g 路由器间歇性地访问互联网

通过我的移动路由器 (tplink mifi m7350) 的连接不再工作，我不明白为什么。使用“家庭路由器”或手机网络共享时，wifi 连接正常。

手机（android）使用的相同路由器完美运行：

• 连接到路由器本身http://192.168.0.1显示管理应用程序，它声明连接到 PC 和手机）
• 手机可以上网

从 Ubuntu 我可以看到路由器已连接，一个 ip 已分配

$ nmcli device show wlp3s0 
GENERAL.DEVICE:                         wlp3s0
GENERAL.TYPE:                           wifi
GENERAL.HWADDR:                         C0:CB:38:37:80:CE
GENERAL.MTU:                            1500
GENERAL.STATE:                          100 (connected)
GENERAL.CONNECTION:                     TP-Link_8B6B
GENERAL.CON-PATH:                       /org/freedesktop/NetworkManager/ActiveConnection/28
IP4.ADDRESS[1]:                         192.168.0.136/24
IP4.GATEWAY:                            192.168.0.1
IP4.ROUTE[1]:                           dst = 0.0.0.0/0, nh = 192.168.0.1, mt = 600
IP4.ROUTE[2]:                           dst = 192.168.0.0/24, nh = 0.0.0.0, mt = 600
IP4.ROUTE[3]:                           dst = 169.254.0.0/16, nh = 0.0.0.0, mt = 1000
IP4.DNS[1]:                             192.168.0.1
IP6.ADDRESS[1]:                         fe80::5a50:d171:52d3:a730/64
IP6.GATEWAY:                            --
IP6.ROUTE[1]:                           dst = ff00::/8, nh = ::, mt = 256, table=255
IP6.ROUTE[2]:                           dst = fe80::/64, nh = ::, mt = 256
IP6.ROUTE[3]:                           dst = fe80::/64, nh = ::, mt = 600

路由表似乎没问题：

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         lrkwz-Precision 0.0.0.0         UG    0      0        0 wlp3s0
link-local      0.0.0.0         255.255.0.0     U     1000   0        0 wlp3s0
(...)
192.168.0.0     0.0.0.0         255.255.255.0   U     600    0        0 wlp3s0
192.168.0.0     0.0.0.0         255.255.240.0   U     0      0        0 br-5a71a323fc97
192.168.16.0    0.0.0.0         255.255.240.0   U     0      0        0 br-9155247a5500
192.168.32.0    0.0.0.0         255.255.240.0   U     0      0        0 br-72b41f5e1bf7
192.168.48.0    0.0.0.0         255.255.240.0   U     0      0        0 br-04bf5a3cdf1e
192.168.64.0    0.0.0.0         255.255.240.0   U     0      0        0 br-63c28b3c6d04
192.168.80.0    0.0.0.0         255.255.240.0   U     0      0        0 br-0ab70b5d8d47

...但互联网访问是断断续续的：即我可以请求一个页面，但我不能请求两个，甚至在同一个页面加载会话中，一些资源被获取，有些则没有。我可以 ping 一次，但第二次失败并显示“无法访问主机”消息。

前几天apt upgrade升级了博通的驱动：

Log started: 2019-06-28  17:15:16
Selecting previously unselected package linux-modules-4.15.0-54-generic.
(...)
Removing linux-image-4.15.0-52-generic (4.15.0-52.56) ...
/etc/kernel/prerm.d/dkms:
dkms: removing: bcmwl 6.30.223.271+bdcom (4.15.0-52-generic) (x86_64)
-------- Uninstall Beginning --------
Module:  bcmwl
Version: 6.30.223.271+bdcom
Kernel:  4.15.0-52-generic (x86_64)
-------------------------------------
(...)
Setting up linux-headers-4.15.0-54-generic (4.15.0-54.58) ...
/etc/kernel/header_postinst.d/dkms:
 * dkms: running auto installation service for kernel 4.15.0-54-generic

Kernel preparation unnecessary for this kernel.  Skipping...
applying patch 0002-Makefile.patch...patching file Makefile
Hunk #1 succeeded at 113 with fuzz 1.
Hunk #2 succeeded at 132 with fuzz 2 (offset 1 line).

applying patch 0003-Make-up-for-missing-init_MUTEX.patch...patching file src/wl/sys/wl_linux.c
Hunk #1 succeeded at 111 with fuzz 2 (offset 12 lines).

applying patch 0010-change-the-network-interface-name-from-eth-to-wlan.patch...patching file src/wl/sys/wl_linux.c
Hunk #1 succeeded at 221 (offset -14 lines).

applying patch 0013-gcc.patch...patching file Makefile

applying patch 0019-broadcom-sta-6.30.223.248-3.18-null-pointer-fix.patch...patching file src/wl/sys/wl_linux.c
Hunk #1 succeeded at 2169 (offset 12 lines).

恢复到基本驱动程序没有区别（除了“设备不工作”而不是“此设备正在使用替代驱动程序”注释）

编辑：

Tplink 路由器绝对可以与其他 PC 一起使用（我恢复了旧的 Windows Vista 机器和 Android 手机）。

ubuntu PC 上的 Wifi 使用另一个路由器工作：

$ iwconfig wlp3s0
wlp3s0    IEEE 802.11  ESSID:"lrlwz-A5"  
          Mode:Managed  Frequency:2.412 GHz  Access Point: D4:AE:05:90:F8:DF   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on

但是 Tplink wifi 仍然没有运气（即使在硬件重置和交换 SIM 卡之后）：

$ iwconfig wlp3s0
wlp3s0    IEEE 802.11  ESSID:"TP-Link_8B6B"  
          Mode:Managed  Frequency:2.442 GHz  Access Point: C4:71:54:EB:8B:6B   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on

关于卡的一般信息：

$ sudo lshw -class network
(...) 
  *-network
       description: Wireless interface
       product: BCM43224 802.11a/b/g/n
       vendor: Broadcom Inc. and subsidiaries
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlp3s0
       version: 01
       serial: c0:cb:38:37:80:ce
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=wl0 driverversion=6.30.223.271 (r587334) ip=192.168.43.43 latency=0 multicast=yes wireless=IEEE 802.11
       resources: irq:17 memory:e6e00000-e6e03fff

如何诊断问题？