Jim, When you encapsulate your router interface with dot1q you are turning it into a trunk port. All of the traffic coming out of that port will be tagged with a vlan id except for traffic generated on the native vlan. By default, any subinterface encapped with vlan 1 will be native and its traffic will be untagged. If you want a subinterface other than one encapped as vlan 1 to generate untagged frames, then you will need to add the "native" keyword to the end of the encap statement.
BTW: 1. Encapping subifs to dot1q makes that interface a trunk port, but not a switch port (does not generate stp frames, e.g). 2. You need to connect this router port to a switch port that is a dot1q trunk, and the native vlans must match (if you want it to work). I have an Ethereal capture of traffic from such a port showing the native vlan traffic untagged if you are interested. HTH, -Bob Sinclair CCIE #10427, MCSE Senior Network Engineer Networking For Future, Inc. www.nffinc.com ----- Original Message ----- From: "Jim Devane" To: Sent: Tuesday, March 04, 2003 10:49 PM Subject: Native VLAN question [7:64431] > I am kinda new to VLANs and need some advice. > I have a router which I have broken an interface into FastEthernet > subinterfaces. Each subinterface defines the VLAN. This has worked very > well. But I am wondering if it is possible to make this port a trunk port > and have other non-tagged traffic arrive on this port as well. > Basically, I want to have tagged traffic and untagged traffic go to the same > Ethernet port, route the untagged traffic and tag the VLAN traffic. I am not > sure if I can have both types of frames on the same port > I have posted my router's config below: > I need to know how to allow other untagged traffic to be recieved on this > port. > > thanks, > jim > interface FastEthernet0/1 > description TRUNK_PORT > no ip address > no ip directed-broadcast > no ip mroute-cache > load-interval 30 > duplex full > ! > interface FastEthernet0/1.25 > description VLAN > encapsulation dot1Q 25 > ip address 192.168.64.101 255.255.255.252 > no ip directed-broadcast > ! > interface FastEthernet0/1.26 > description VLAN 26 > encapsulation dot1Q 26 > ip address 192.168.64.97 255.255.255.252 > no ip directed-broadcast Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=64477&t=64431 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
