The Mixed port is a port where tagged and untagged traffic is allowed. However, on ingress, a
default VLAN tag is assigned to untagged traffic (configured by QOS and VLAN commands), so
that all frames in the system are actually tagged. On egress frames with VLAN equal to the default
VLAN (configured with VLAN command), exit the port untagged, while to all other VLANs apply
pass/block rules set by the ALLOW command.
Table 3.8 Access, Trunk and Mixed Mode
Orion3 devices always transmit Ethernet packets over DSL or E1 interfaces with the VLAN format.
It means that data packets coming from Access ports are first transformed into Ethernet packets
with VLAN format (adding standard VLAN number and QoS priority level) and after this
transmitted over any line interface.
There is a special case when having the same MAC address on different VLANs and PBVLANs.
Normally, there should not be two devices on the network sharing the same VLAN. But IEEE
802.1Q VLANs as well as port-based VLANs allow creating separate logical networks on one
physical network. Thus, in different VLANs or PBVLANs there could be devices sharing the same
MAC address. On Orion3, however, there is a hardware limitation preventing all VLAN+PBVLAN
combinations from having different address databases, and therefore, allowing same MAC
address to be used on all VLAN&PBVLAN combinations is possible in the modem configuration.
But, knowing which configurations are valid will allow using modems in all really vital
configurations. There are two rules.
1. For separately managed VLANs 1-8. Each VLAN has its own MAC address table, and thus
device with MAC address ABC in each of these 8 VLANs will not conflict with any device with
MAC address ABC in any other VLAN. But the limitation here is the use of port-based VLANs.
MAC address database is shared among all PBVLANs for VLAN1-8. Therefore a device with
MAC address XYZ, VLAN1, PBVLAN A, will conflict with device with MAC address XYZ,
VLAN1, PBVLAN B.
2. For all other VLANs. Here, every PBVLAN has its own MAC address table, but different
VLANs on one PBVLAN share the same database. A device with the MAC address XYZ,
VLAN(any other), PBVLAN A, will not conflict with a device having the MAC address XYZ,
VLAN(any other), PBVLAN B. But the device with the MAC address ABC, VLAN(any other),
PBVLAN A, will conflict with the device having the MAC address ABC, VLAN(any other+1),
PBVLAN A.
To Next Page
Loading...
