dot1q and 802.1Q
Bolton07
Member Posts: 87 ■■□□□□□□□□
in CCNA & CCENT
Are dot1q and 802.1Q encapsulation the same thing?
Could someone please explain them please if they are not
Could someone please explain them please if they are not
Comments
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ehnde
Member Posts: 1,103
They are the exact same thing, just a different way of describing dot1q. Which is easier to type?
Climb a mountain, tell no one. -
Bolton07
Member Posts: 87 ■■□□□□□□□□
Why when configuring inter-vlan routing like below do you configure an Fastethernet interface with no ip address or subnet mask?
To configure inter-VLAN routing, use the following steps:
1. Configure a trunk port on the switch.
Switch(config)#interface fa0/2
Switch(config-if)#switchport mode trunk
2. On the router, configure a FastEthernet interface with no IP address or subnet mask.
Router(config)#interface fa0/1
Router(config-if)#no ip address
Router(config-if)#no shutdown
3. On the router, configure one subinterface with an IP address and subnet mask for each VLAN. Each subinterface has an 802.1Q encapsulation.
Router(config)#interface fa0/0.10
Router(config-subif)#encapsulation dot1q 10
Router(config-subif)#ip address 192.168.10.1 255.255.255.0 -
Forsaken_GA
Member Posts: 4,024 ■■■■■■■■■■
You can't configure dot1q encapsulation on the main interface -
Bolton07
Member Posts: 87 ■■□□□□□□□□
But why do you even have to type commands below?
Are these commands optional?
2. On the router, configure a FastEthernet interface with no IP address or subnet mask.
Router(config)#interface fa0/1
Router(config-if)#no ip address
Router(config-if)#no shutdown -
Forsaken_GA
Member Posts: 4,024 ■■■■■■■■■■
Well, if you want the interface to actually handle any traffic, then the no shutdown command is pretty mandatory, assuming the interface is admin down. If it's already up, then it's not strictly necessary. The book is probably coming at it from the standpoint of no prior configuration, and by default, router interfaces are down.
The no ip address may or may not be mandatory. If the only thing you're doing is routing tagged vlans through the router on a stick, then no, you don't want the physical interface to have an IP address. If you're making use of the native vlan (and therefore, some traffic is not tagged), then you can address the physical interface with an IP in the native vlan's subnet.