SG-1100 and "Port VID" for the Router-On-A-Stick
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OK so for the HOW TO GUIDE for this, in step 11 we are told to go to port 1 (OPT port) and change its PortVID from 4092 to 1.
What is that all about? and why is it needed as in step 10 we are setting all 3 VLANs (4090 - 4092) with members of "1t" which is my understanding of how we tell the system to use vlan tags for those vlans' traffic on port 1 the OPT port we are trying to do the router on a stick with.
So then that step 11 then makes me unsure that my understanding of what is going on in step 10 is all about.
Can an expert comment in on what the difference is on "PORT VID" and the "Members with the 't' designation"?
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The PVID on the port determines the VLAN an untagged packet arriving on that port will be placed onto.
In the default configuration VLAN 4092 has port 1 as an untagged member so traffic in the switch on 4092 will leave port 1 untagged. For two way traffic to work untagged traffic arriving at port 1 needs to be tagged back onto 4092 hence the port 1 PVID is 4092.
In the router-on-a-stick configuration traffic on VLAN 4092 is now leaving port 1 tagged 4092. Reply traffic will also be tagged so the PVID is not required. And in fact having the PVID at 4092 is undesired because it would put untagged traffic on port 1 onto 4092 with no way to reply. So we set the PVID there to 1 which effectively drops the traffic since nothing is listening on port 0 untagged. It could be also be set to any unused VLAN ID.Steve
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@stephenw10 I think I get it. so its kind of a difference between transmit and receive?
where setting the PVID would be "receive" where we tell the system what vlan to classify an untagged frame into?
and where setting "member" with port# and a t (or not a t) would be "transmit"?
if so I believe I got it and thanks VERY much!
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Yes, that's pretty much it.
So it's possible (but almost always wrong!) to have several VLANs untagged on a port but you can only ever tag back one VLAN ID the other way.
Steve
