>Cisco 1750 (как и 1720) НЕ ПОДДЕРЖИВАЕТ 802.1Q или ISL. Вообще никак.
>Софт тут непричем.
Вы это на 100% знаете (прошу прощения за мои сомнения)?
Ведь в документации по 1700, 1751 (чисто по 1750 не нашёл)сказано обратное, мол поддерживает порт FastEthernet инкапсуляцию dot1q, настраивать так то и так то.
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IEEE 802.1Q support is currently available for Fast Ethernet interfaces.
Configuring IP Routing over IEEE 802.1Q
IP routing over IEEE 802.1Q extends IP routing capabilities to include support for routing IP frame types in VLAN configurations using the IEEE 802.1Q encapsulation. To route IP over IEEE 802.1Q between VLANs, you need to customize the subinterface to create the environment in which it will be used. Perform these tasks in the order in which they appear:
• Enabling IP Routing
• Defining the VLAN Encapsulation Format
• Assigning IP Address to Network Interface
Enabling IP Routing
IP routing is automatically enabled in the Cisco IOS software for routers. To reenable IP routing if it has been disabled, use the following command in global configuration mode:
ip routing
Once you have IP routing enabled on the router, you can customize the characteristics to suit your environment.
Defining the VLAN Encapsulation Format
To define the encapsulation format as IEEE 802.1Q, use the following commands in interface configuration mode:
interface fastethernet slot/port.subinterface-number
encapsulation dot1q vlanid
Assigning IP Address to Network Interface
An interface can have one primary IP address. To assign a primary IP address and a network mask to a network interface, use the following command in interface configuration mode:
ip address ip-address mask