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vlan.?????

ouartil
Level 1
Level 1

hi, i am very confiused with vlans,

i have a manageble switch 3com, i wanted tu test the vlan to show to a girl that i am mister vlan!!,

so i create vlan 2 and vlan 3, and there is a default vlan 1. i putted my computer on a port in vlan 2, and another computer in vlan 3, and i have tried a ping between them, i expected not to work, and it work, i have waited 5 mn, and it could still ping between 2 differnet vlans.

why?

thanks.

6 Replies 6

jawad1979
Level 1
Level 1

Hi,

Depending on your 3Com switch, a Layer 3 switch might be configured to route between the Vlans.

Jawad

hi, i am she, it's a layer 2 switch, and there are no router on a stick.

thanks.

Hi,

Creating a VLAN will only create VLANs on the switch. Each port need to subscribe to a particular VLAN. I guess you have subscribed ports to VLAN2 nad VLAN3 and you are connecting 2 PCS into these ports. IF not then as default all Switch ports remain part of Management VLAN1. Hence you will be able to ping.

Regards

Shaheen

i am sure, every think is well done, i have created the 2 vlan, and a assign my pc to vlan 2,and another pc to vlan 3, and the ping work.

thanks.

My guess is, on the 3Com switch you have added VLAN 2 as tagged to one port, and VLAN 3 as tagged to the other, but both ports are still in VLAN 1 as untagged.

Each computer sends its data traffic without VLAN tag information (unless it has a server NIC that can send and receive tagged frames). The 3Com switch receives the traffic, doesn't see any VLAN tag information on the frames, so it forwards the traffic on the untagged VLAN for that port. If both switch ports have the same untagged VLAN, then the two computers can still ping each other.

What kind of 3Com switch is it? On a Switch 1100 or 3300, for example, the "bridge port detail" command followed by the port number will show you the VLANs a port belongs to. Tagging will be either "None" (untagged) or 802.1Q (tagged). On these switches, in the web browser interface the untagged VLAN is assigned port by port; while tagged VLANs are assigned in the screen where you can also add, modify and delete VLANs.

Hope this helps.

i found the solution,

it was the port itself, when i got to the configuration of the port, i found that encapsulation 802.1q was desabled, i have enabled it and it worded.

thanks folks.