The Graveyard - Products No Longer Supported > DGS-1224T
difference between untagged VLAN and PVID
chrpinedo:
Hello all,
this is my first post in the forum. We have more than 10 DGS-1210-24 switches in our LAN network and I don't understand well the difference between an untagged VLAN in a port and the PVID of a port.
I am more accustomed to Cisco switches. In Cisco switches there are only untagged and tagged VLAN in a port, not the PVID for a port.
So what is the difference between set a VLAN untagged in a port and set PVID for the same port???
Thanks,
Christian
fles_dnoyeb:
Tagged/untagged has to do with how packets leave the switch. PVID controls which VLAN untagged packets that enter the switch belong to. In theory.
Sometimes with the behavior of the switch I am not so sure...
Planck:
Here's the quick overview on this topic:
Tagged traffic: Is used between tag-aware units (Switches and AP's), so they can see what VLAN the traffic belongs to. In short, if you use one cable between two switches, you will have to tag traffic. You can have one untagged all the way around in the network, but the next VLAN's have to be tagged.
PVID: Port VLAN ID is used to untag traffic befor it leaves the switch. If you have one unit/PC, that you only wanna use in VLAN 4, then you set the port it is connected to to VLAN 4, and only that traffic will be send to that specific port.
Best practice:
VLAN 1 untagged in all of the network, and the rest is tagged. When you need to extract one VLAN to a specific port, you will need to assign the PVID to the correct VLAN.
If you have any further questions, then you can ask here: http://structureit.dk/forum/
Best regards
Planck
dmx.tech:
This may help any body who is confused by these terms. Like i was and spent month reading and testing about it.
This can be helpful to you if you have 2 switch and want to use a single cable to link both switch for many Vlan. If you have only 1 switch then your network card need to support 802.11q. You can create multiple vlan in your pc then connect to your switch. That link wil be called trunk.
I assume anybody who will read this already know the basic of Vlan. The port that will connect to the PC or Other switch from your switch need to be set as TAGGED. When you set it as tagged you instruct the switch that data packets that will go through it is already tagged. You can have many vlan data packets via a switch port with is set as tagged. Untagged ports are member of a vlan and PVID is for non tagged packets arriving at a port on the switch.
If a packet arrives at the port from an end device carrying no VLAN tag, then the switch will add a VLAN tag which corresponds to the PVID, and then forward it within that VLAN; so the PVID mechanisim allows you to have traffic originating from a non-VLAN aware device to become an 802.1q packet, so that it can traverse to other switches and still be contained within the correct VLAN.
xorken:
--- Quote from: dmx.tech on May 29, 2016, 06:51:36 AM ---This may help any body who is confused by these terms. Like i was and spent month reading and testing about it.
This can be helpful to you if you have 2 switch and want to use a single cable to link both switch for many Vlan. If you have only 1 switch then your network card need to support 802.11q. You can create multiple vlan in your pc then connect to your switch. That link wil be called trunk.
I assume anybody who will read this already know the basic of Vlan. The port that will connect to the PC or Other switch from your switch need to be set as TAGGED. When you set it as tagged you instruct the switch that data packets that will go through it is already tagged. You can have many vlan data packets via a switch port with is set as tagged. Untagged ports are member of a vlan and PVID is for non tagged packets arriving at a port on the switch.
If a packet arrives at the port from an end device carrying no VLAN tag, then the switch will add a VLAN tag which corresponds to the PVID, and then forward it within that VLAN; so the PVID mechanisim allows you to have traffic originating from a non-VLAN aware device to become an 802.1q packet, so that it can traverse to other switches and still be contained within the correct VLAN.
--- End quote ---
Hello, im still not sure if I fully understand the concept of PVID.
Take a Cisco switch for example, a port that is set to be member of Untagged VLAN100. Would'nt that port always asume that every packet that ingresses on that port would be member of that VLAN? And if there's also a tagged/trunk port on that switch which VLAN100 is a member of, that packet that came in on the untagged port, would get an 801.1q tag and sent out the trunk/tagged port
Navigation
[0] Message Index
[#] Next page
Go to full version