I try to connect real switch with my computer for an exam preparation, for this purpose I need more than one LAN cards, and there is only one built in LAN card in my computer. So, to get more LAN cards, I bought 4 USB Ethernet adapters (as I have 4 usb ports in may laptop 2 usb 2.0 ports, 2 usb 3.0 ports).

When I plug these adapters in my computer Ubuntu only detects one LAN card from 2.0 usb ports, and one LAN card from 3.0 ports. And sometimes detects only one USB LAN from all the usb ports.

Actually the real problem is Ubuntu shows these USB LAN adapters in the "lsusb", but does not list them in "ifconfig".

Kontron (Industrial Computer Source / ICS Advent) is my LAN USB ethernet.

abc@ubuntu:~$ lsusb

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hu
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hu
Bus 002 Device 012: ID 0fe6:9700 Kontron (Industrial Computer Source / ICS Advent)
Bus 001 Device 003: ID 138a:0018 Validity Sensors, Inc.
Bus 001 Device 004: ID 064e:e258 Suyin Corp.
Bus 003 Device 011: ID 0fe6:9700 Kontron (Industrial Computer Source / ICS Advent)
Bus 002 Device 013: ID 0fe6:9700 Kontron (Industrial Computer Source / ICS Advent)
Bus 003 Device 012: ID 0fe6:9700 Kontron (Industrial Computer Source / ICS Advent)
Bus 002 Device 005: ID 0a5c:21b4 Broadcom Corp. BCM2070 Bluetooth 2.1 + EDR

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etho is my built in LAN card, while eth1 is the only USB LAN card that ubuntu has detected.

abc@ubuntu:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 2c:27:d7:a5:d2:39
          inet6 addr: fe80::2e27:d7ff:fea5:d239/64 Scope:Link
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:21056 errors:0 dropped:1 overruns:0 frame:0
          TX packets:5669 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1407289 (1.4 MB)  TX bytes:372566 (372.5 KB)
          Interrupt:49 Base address:0xa000 

eth1      Link encap:Ethernet  HWaddr 00:e0:4c:53:44:58
          inet6 addr: fe80::2e0:4cff:fe53:4458/64 Scope:Link
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:9230 errors:0 dropped:0 overruns:0 frame:0
          TX packets:9230 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:557648 (557.6 KB)  TX bytes:557648 (557.6 KB)

wlan0     Link encap:Ethernet  HWaddr cc:52:af:5e:78:05 
          inet addr:192.168.1.65  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::ce52:afff:fe5e:7805/64 Scope:LinkU
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:17389 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12231 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:22452248 (22.4 MB)  TX bytes:1502750 (1.5 MB)

If I unplug the USB LAN card which Ubuntu has detected, then Ubuntu will detect a USB LAN card from the remaining plugged adapters, and process go on untill I plug all the USB LAN adapters.

Looking for some urgent help. Thanks