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Questions tagged [dot1q]

For questions about IEEE 802.1Q also referred to as Dot1q, which is the networking standard that supports virtual LANs (VLANs) on an IEEE 802.3 Ethernet network. For instance, you are setting up two switches and want to use trunk between them, but do not know how.

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2answers
281 views

L2 / L3 on CISCO ASR

I am new to CISCO and have the following problem: I have 3 routers. Between these only one physical connection. The VLAN 100 is connected to R1 and R2. The VLAN 200 is connected to R1, R2 and R3. The ...
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vote
1answer
133 views

Layer 3 switch model 3950 encapsulation

How to ensure trunk link in the switch are using dot1q encapsulation, when dtp (dynamic trunking protocol) is enable along with vtp. I know when manually setting trunk links, you can force the trunk ...
3
votes
1answer
212 views

Dot1q tags, sub-interfaces

Please consider dot1q frames tagged 100 circulating on a LAN (VLAN 100). To go out onto the Internet, frames have to go through a PPPoE sub-interface which is configured as below: interface ...
5
votes
1answer
264 views

Juniper EX4600: multicast not working in vlan default. [closed]

I have a Juniper EX4600 switch which I'm using for host connectivity (obviously). Now I need to set up a VRRP/CARP between two hosts that are in the same vlan, and it's the default one. Surprisingly, ...
1
vote
1answer
62 views

Bridge traffic forwarding in vlans

on a trunk, switch A having, say vlan 10 allowed and the other switch B does not. Switch B doesn't even know about that vlan. How does switch A behave in forwarding broadcasts in vlan 10? Will frames ...
5
votes
3answers
2k views

Cisco QinQ - More than one provider vlan (s-vlan) on dot1q-tunnel port

When we configure a qinq tunneling, the port, which performs the encapsulation, has the next command-lines: interface g0/10 switchport switchport mode dot1q-tunnel switchport access vlan xxx &...
3
votes
1answer
114 views

Respect VLAN through routers with DHCP server on WAN

I would like to create a network like the one in the screenshot. I would have 2 VLANs : -VLAN10 : Service1 -VLAN20 : Service2 Routing is working but i don't know if I can have adresses on 192.168.1....
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0answers
503 views

Juniper EX3300 and Q-in-Q

I have a Juniper EX3300 switch that has a 10Gbps connection to our upstream provider. Our upstream provider (lets call them Provider A) passes us various connections on tagged VLANs over this single ...
3
votes
1answer
3k views

Cisco 891: sub-interface VS SVI approach

I have a SOHO environment for which I'm using Cisco 891-K9 as the ISP GW. But the nature of Cisco 891 is that it's both a router and a switch with 10 ports. Will switch ports (both access and trunk ...
0
votes
1answer
868 views

Multiple VLANs on a single port Virtual Host

I have a physical host server connected to an HP (say, 2650 series?) switch. The host is running multiple Hyper-V virtualized OSes, each on a different VLAN. If I make the switch port dot1q tagged for ...
3
votes
1answer
404 views

Cisco router dot1Q monitoring

How can I monitor on a Cisco router if dot1Q packets arrive on the trunk interface or if others arrive on that interface (like ISL, the old protocol of Cisco)? How can I do this and what is the best ...
9
votes
1answer
2k views

Dell powerconnect 6248 voice vlan next to dot1x

We are testing currently dot1x auth against FreeRADIUS/AD in the network. The vlans are dynamically assigned by FreeRADIUS on AD-group base. This works, but now the problem comes: We wanted to add ...
24
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5answers
25k views

Accidentally Removed Allowed VLANs from Cisco Switch Dot1Q Trunk

I am adding a new VLAN to an existing trunk port between two Cisco Catalyst switches (3750's). In the process of adding the new VLAN, it appears that I've removed the existing allowed VLANs on the ...