Switching config

Hi i have a scenario here..........
i have 3 switches A,B,C connected to eachother(may or maynot be a trunk link). SW A has a user at vlan 10 and SW C has a user at vlan 10. Any communication between A & C has to pass through SW B. So can SW A user ping the user at SW C, if yes how :roll: if no why :idea: ???????

So can SW A user ping the user at SW C, if yes how :roll: if no why :idea: ???????

Yes it can, there are multiple ways to do it. I'm assuming here you already set users ports to vlan 10 on the switches. The following is the typical setup:

1. Both links between A,B and between B,C has to be configured as trunk.
2. All three switches must be part of the same VTP domain.
3. One of the switches has to be configured as a VTP server and the other two has to be clients.

Another way without using trunk ports, is by setting all A,B and C,D links ports to "access" vlan 10. And configuring all switches as VTP servers. But this is not very recommended.

Don't hesitate to ask any further questions

Thanks SOLOOOO...

i have one more question 4 u
how will SW B process the frame if VTP is not enabled in any of the switches??

When they are configured as trunk ports What will be SW B behavior when it receives the frame from SW A??? :roll:

Thanks SOLOOOO...

i have one more question 4 u
how will SW B process the frame if VTP is not enabled in any of the switches??

Sure m2r007

When you disable VTP (by setting the switch to transparent mode) the switch will act as it's own server for VLAN information. But it will not send it's VLAN information to other clients and it will not update it's VLAN information from other servers. The only thing transparent switches do is forward VLAN information that they receive from switches out their trunk ports. There are some more details to this regrading version differences.

Back to your question. If VTP is disabled (transparent switches). And you configured no trunk ports. Just all ports (link and users) ports assigned to VLAN 10. Then yes, again users will be able to do communication between A and C.

Switch B will simply take the untagged frame it received from switch A and forward it to the right VLAN 10 port (that connects it to Switch C). (Or broadcast it to all VLAN 10 ports and other trunks if this is the first time, were there is no MAC entry for the user in the CAM table of switch

When they are configured as trunk ports What will be SW B behavior when it receives the frame from SW A??? Rolling Eyes

Frames that run through trunk ports are tagged for the corresponding VLAN. The tags are removed once the frame gets out of an access port. So B will receive frames from A tagged for VLAN 10. It will keep it tagged and send it to the trunk port to C (But first time is broadcast to all vlan 10 ports and trunks). C will then untag the frame and send it to the correct user access port (again, first time is broadcast).

Thats as far as I know, any corrections and comments and welcome.

Many Many thanks genius SOLO!!!!!!!!!
That was actually a interview question