Vlan Aware Mode - 3Com corebuilder 3500 Implementation Manual

174 C 9: V
HAPTER IRTUAL

VLAN Aware Mode

LAN
S
VLAN aware mode accommodates the difference in VLAN resource usage
as well as tagged-frame ingress rules between Release 1.2 and
Release 3.0 of the system software. For more information on ingress
rules, see "Rules of VLAN Operation" later in this chapter. (The Release
1.2 ingress rules in allOpen mode mandated that incoming tagged
frames assigned to one of the configured VLANs if the VID of the frame
matched that of the VLAN and if a port in that VLAN were tagged.)
The VLAN aware mode, which you set with the Administration Console
option
bridge vlan vlanAwareMode
resource usage and modes of tagging as follows:
At Release 1.2, all bridge ports were not VLAN aware (tagging aware)
unless they were assigned to a VLAN that has one or more tagged
ports.
At Release 2.0 and later, all bridge ports become VLAN aware after a
software update or after an NV data reset and do not have to be
explicitly tagged in order to forward tagged frames.
This difference in resource usage and modes of tagging has the following
impact: After you upgrade the system from 1.2 to 3.0, the release uses
VLAN resources differently than it did at Release 1.2 and may cause a
change in the total number of allowable VLANs.
VLAN aware mode is currently supported only through the
Administration Console, not through Web Management or SNMP.
Initial installation of Release 3.0 provides a default VLAN aware mode of
allPorts, which is consistent with the Release 3.0 ingress rules and
resource allocation.
If you upgrade your system from Release 1.2 to a later release and the
VLAN resource limit is reached during a power up with a serial port
console connection, the system displays an error message similar to the
following one to identify the index of the VLAN that it was unable to
create:
Could not create VLAN xx - Internal resource threshold
exceeded
, reflects the difference in VLAN