Star Microwave SM Cirius LM, User Manual

Page: 64 / 79

Cirius LM User Manual 2016 Page 64
tagged. VLAN tags added by the switch are removed upon egress from the link.
Therefore, frames that ingress to the switch with a single VLAN tag egress from the
terminal with their original VLAN tag intact. However, frames that ingress to the link
double-tagged will have their 2
nd
tags removed. Both terminals of a link must have
VLAN Security enabled for protection to be in effect.
Also note that both terminals of a link must have the same VLAN Security setting
(enabled or disabled) in order to have remote management access to the far-side
terminal. Therefore, if VLAN Security is to be changed in a link, it is necessary that
the far-side terminal be commanded first prior to changing the near-side.
For the purposes of address lookup and frame forwarding functions, each of the
three distinct VLANs defined within the switch have a separate address database
associated with it. In this way, the two transport ports can pass frames with
identical destination addresses without problems related to inconsistencies
between destination addresses and learned port vector assignments.
Figure 38 VLAN-based Security Design
4.2. Port Based QoS Priority Features
The platform allows the assignment of one of four priority levels to each ingress
port. When the QoS Priority feature is enabled, all frames ingressing into a given
port are tagged with the priority level assigned to that port. The frames’ priority
levels are then used within the switch’s queue controller to determine with what
priority the frames are allowed to egress from the egress port(s) to which they are
switched. The priority level assigned to each ingress