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Virtual Interfaces with NM-16ESW

Unanswered Question
Apr 7th, 2003
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In order to create a dot1q trunk to an NM-16ESW so that virtual interfaces can be used, must the trunk be created using a standard router fastethernet interface (like fa0/0) and a patch cable to a port on the switch module thus requiring dot1q encapsulation on sub-interfaces?

If that is the case, all switch ports will share the 100 meg uplink and essentially the only thing that the router would be providing is power.

The documentation alludes to "virtual interfaces" and that vlan1 is created automatically. But it doesn't mention anything about running a cable from a router interface to a switch-module port or having to configure the encapsulation or using sub-interfaces.

What am I misunderstanding?


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tcross3 Mon, 04/07/2003 - 20:51
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The switch blade give you the ability to create switched vlans. This link refers to creating vlans on an IOS swithc whic is waht you have when you use this blade;http://www.cisco.com/en/US/products/hw/switches/ps637/products_configuration_guide_chapter09186a008007f261.html. Dot1q encapsulation is used when you are using router interfaces for example;

interface FastEthernet1/0

no ip address

speed auto


no mop enabled

interface FastEthernet1/0.107

encapsulation dot1Q 107

ip address

You should not connect the router to itself. What are you trying to accomplish?


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