topic Re: p-Class GbE2 Switch (Blade) in Switches, Hubs, and Modems

p-Class GbE2 Switch (Blade)

Stuart Teo — Thu, 13 Oct 2005 18:31:51 GMT

I have a p-Class GbE2 Switch and I have a question regarding vlan tagging.

I have port 1 (blade 1, NIC1) tagging enabled and I noticed that the port started tagging even for the default PVID. Is this the correct behavior? I thought that the default PVID is always not tagged????????

Thanks.

Re: p-Class GbE2 Switch (Blade)

Connery — Sat, 15 Oct 2005 12:38:05 GMT

The GbE2 tags all VLANs - including the default/native VLAN.

Cisco by default does not tag the native VLAN but they do provide a command to tag the native if desired (vlan dot1q tag native).

There is a slight difference between GbE2 tagging the native and Cisco tagging the native VLAN. Even with the GbE2 tagging the native VLAN, it will still accept untagged frames and classify the frames as the native VLAN ID (PVID). Whereas with Cisco, when you enable tagging of the native VLAN, all untagged frames are dropped.

Tagging of the native VLAN is actually safer. If you have different native VLANs accidentally configured on both sides of a point to point link, tagging the native VLAN will still allow all traffic to pass without getting classified as the wrong VLAN.

Bottom line is that it shouldn't cause any problems. If anything, it will prevent problems.

Regards,
-sean

Re: p-Class GbE2 Switch (Blade)

Stuart Teo — Sun, 23 Oct 2005 23:25:35 GMT

i've found ports 1-16 behavior to be inconsistent with ports 17-24. :( with tagging turned on, ports 1-16 tags all vlans. while ports 17-24 tags only non-pvids. :( anyone else experiencing this?