3Com Vlans and tagged ports 1

[marks99]

Hi,

I've got a 3com 4900 switch and a 3com 4924 switch connected over a fibre link, Vlan1 is untagged, and I have several other tagged vlans over the link. I need to setup a new Vlan which will be visible on both sides of the link.

As I understand it, if I setup the tagged port on one side of the connection I will loose connectivity until the opposite port is tagged with the Vlan. Is this correct? or is there any way around this?

Thanks

 

[IRudebwoy]

I'm not too sure what you are trying to explain.

Ethernet ports can be a member of multiple tagged VLANs and can only be a member of 1 untagged VLAN.

As I understand it, if I setup the tagged port on one side of the connection I will loose connectivity until the opposite port is tagged with the Vlan. Is this correct? or is there any way around this?

Huh?

If you add untagged ports to a VLAN that port will be shut down and re-enabled with the new membership. This shouldn't effect connectivity elsewhere except on the port whose VLAN membership changed. Making a port a tagged mamber of a VLAN should not have a noticable effect.

A bit more detail might prove useful. What are trying to accomplish?

 

[marks99]

Apologies if I did not make myself clear,

I understand that changing the untagged vlan membership will reset the port.

I am trying to add an additional trunked vlan between two switches which already have a number of trunked vlans.

My understanding is that if I make a port a tagged member of a vlan on one switch, I will lose connectivity between the switches until I tag the corresponding port on the second switch.

If this is the case I'll plan some downtime, if not I can go ahead and tag the ports without any risk of downtime.

I appreciate your advice.

 

[IRudebwoy]

If the same VLAN is defined on either switch they won't be able to communicate with each other until the trunk is tagged at either end. The hosts on either dis-jointed VLAN have no communication path with hosts on the other switch until the trunk is tagged properly. So, no there will be no disruption in communication.

Tagging additional VLANs on the trunk will not have any noticeable effect on other defined VLANs.

I've added several new VLANs within my network without any complaints or outages.

Have Fun!

 

[marks99]

Thanks