Cabletron Vlan Current Operational Mode

1.3.6.1.4.1.52.4.1.2.16.1.3

This value indicates the number of bits in a VLAN Id that are considered significant in the forwarding decision of a packet. This allows VLANs to be grouped together into logical units. Within the scope of these VLAN groups, unicast traffic may be bridged between VLANs, but, multicast and broadcast traffic is scoped to a specific VLAN. In the following depiction M represents the number of significant bits as specified by a set of the object. An X in a box represents that the bit is considered significant based on the value of M. 11 10 9 8 7 6 5 4 3 2 1 0 +===============================================+ M=0 | | | | | | | | | | | | | +===============================================+ 11 10 9 8 7 6 5 4 3 2 1 0 +===============================================+ M=4 | | | | | | | | | X | X | X | X | +===============================================+ 11 10 9 8 7 6 5 4 3 2 1 0 +===============================================+ M=9 | | | | X | X | X | X | X | X | X | X | X | +===============================================+ Significant bits are assigned sequentially starting with bit zero and ending with bit M-1. For a set value of M, (2 ^ M) VLAN groups will be created. Each group will contain (2 ^ (12 - M)) VLAN Ids, with the exception of the first group and last group which will each have ((2 ^ (12 - M)) - 1) VLAN Ids (VLAN Ids 0 and 4095 are reserved). VLAN groups are numbered sequentially from 0 through ((2 ^ M) - 1). The VLAN Ids assigned to each group, N, are assigned sequentially starting with (N * (2 ^ (12 - M))) through ((N * (2 ^ (12 - M))) + ((2 ^ (12 - M)) - 1)), with the exception of group zero which always starts with VLAN Id 1 and group ((2 ^ M) -1) which always ends with VLAN Id 4094. The number of bits specified allows the maximum amount of flexibility in the scoping of traffic, without compromising security between VLANS. For example, a set value of 0 would create a single VLAN group with 4094 VLAN Ids. This configuration would allow all unicast traffic to be bridged between VLANS, while scoping all multicast and broadcast traffic to a specific VLAN. A set value of 12 would restrict all unicast, multicast and broadcast traffic to a specific VLAN. In this configuration no traffic would be bridged between VLANS. Setting of this object is limited to devices which support configurable(2) operational modes as specified by ctVlanSupportedOperationalMode. A set of this object for a device which only supports static(1) operational mode will fail. A read of this object for a device that only supports static(1) operational mode will always return 12.