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New Member

Question regarding VLANs

Hi All,

I'm practicing VLANs for my CCNA and i just got a weird doubt.

My understanding:

By default all the ports of a switch will be in VLAN1. And Access ports doesn't tag any VLAN information, only trunk ports tag VLAN information.;

So if i connect a PC1 to switch0 on its Fa0/10 port, by default PC1 will be in VLAN1

Similarly if i connect a PC2 to a switch0 on its Fa0/20 port (configured to be in VLAN2) PC2 will be in VLAN2.

Likewise if i connect a switch1 to switch0 on Fa0/11 port (This port is in VLAN1) then from the switch0's perspective switch1 is in VLAN1.

So the VLAN1 devices on the switches will be able to communicate properly.

Question:

If i move the port on switch1 which is connected to the Fa0/11 port (in VLAN1) of switch0 to be in VLAN2, then what will happen ?

Will switch0 forward the traffic of VLAN1 on its Fa0/11 port towards switch0's port , if so will switch1's port will accept it /decline it ?

Thanks in advance. Please don't mind if the question seems to be silly.

Regards,

Chandu

Regards, Chandu
Everyone's tags (1)
8 REPLIES
Hall of Fame Super Blue

Question regarding VLANs

Chandu

If i move the port on switch1 which is connected to the Fa0/11 port (in VLAN1) of switch0 to be in VLAN2, then what will happen ?

Will switch0 forward the traffic of VLAN1 on its Fa0/11 port towards switch0's port , if so will switch1's port will accept it /decline it ?

No it will not forward traffic for vlan 1 it will only forward traffic for vlan 2. If you want the link to forward traffic for both it needs to be a trunk link. An access port only carries traffic for one vlan and that vlan is untagged.

Jon

New Member

Question regarding VLANs

Sorry here the questin is : A typo mistake.

-----------------

Will switch0 forward the traffic of VLAN1 on its Fa0/11 port towards  switch1s port , if so will switch1's port will accept it /decline it ?

-----------------

Regards,

Chandu

Regards, Chandu
Hall of Fame Super Blue

Question regarding VLANs

Chandu

Still no. If the port is in vlan 2 then the switch will not forward vlan 1 frames down that link.

Jon

New Member

Question regarding VLANs

Switch0 (Fa0/11) in VLAN1 -----> Switch1 (Fa0/11) in VLAN1...  then devices on both the switches in VLAN1 will communicate.

------

Switch0 (Fa0/11) in VLAN1 -------> Switch1 (Fa0/11) in VLAN2... Then what ?

Question:

The VLAN1 Broadcast/multicast frames will also be received by Fa0/11 port on switch0 because it is configured to be in VLAN1. So the Fa0/11 port on switch1 will see that frame.

Question:

Why don't switch1 takes that frame as a vlan2 frame and flood it for all the ports in VLAN2 on switch1.

Regards,

Chandu

Regards, Chandu
New Member

Question regarding VLANs

Hi Chandra,

                  Yes Chandra, Switch1 will takes that frames as VLAN 2 and flood to VLAN 2 devices.

So now communication as below

VLAN 1 devices in SWITCH0 will communicate with VLAN 2 devices in SWITCH1 and vice versa.

VLAN 1 devices in SWITCH0 will not communicate with VLAN 1 devices in SWITCH1 and vice versa.

Thanks

Venkat

New Member

Question regarding VLANs

Theoritically this is correct.

But if i want to see it practially, is there any way.

FYI: I don't have a real equipment. I'm practicing for my CCNA with the help of PT.

Regards,

Chandu

Regards, Chandu
New Member

Question regarding VLANs

Any update ?

Regards,

Chandu

Regards, Chandu
New Member

Question regarding VLANs

Theoritically this is correct.

But if i want to see it practially, is there any way.

FYI: I don't have a real equipment. I'm practicing for my CCNA with the help of PT.

Regards, Chandu
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