User's Manual

Table Of Contents
281
Users Manual of CS-6306R
27.1.2.8 Transit Node
All switches on the Ethernet except the master node can be called as the transit nodes. The transit node only
checks the state of the local port of the ring, and notifies the master node of the invalid link. See the following
figure, in which S1, S2, S5 and S6 are all transit nodes.
27.1.2.9 Edge Node and Assistant Node
When the sub ring and the major ring are intersected, there are two intersection points, two switches beside
which are called as the edge node for one and the assistant node for the other. The two nodes are both the
nodes of the sub ring. There are no special requirements as to which switch will be set to be the edge node or
the assistant node if their configurations can distinguish themselves. However, one of them must be set as the
edge node and the other must be set as the assistant node. The edge node or the assistant node is a role that
a switch takes on the sub ring, but the switch takes a role of the transit node or the master node when it is on
the major ring. See the following figure, in which S2 is the assistant node and S5 is the edge node.
27.1.2.10 Primary Port and Secondary Port
The two ports through which the master node accesses the Ethernet ring are called as the primary port and
the secondary port. The roles of the two ports are decided by the clients.
The primary port is in forwarding state when it is up. Its function is to forward the packets of the data VLAN on
the master node and to receive and forward the control packets on the control VLAN. The master node will
transmit the loopback detection packets from the primary port to the control VLAN. If the link of the primary
port is resumed from the invalid status, the master node requires sending the address aging notification to the
control VLAN promptly and then starts to transmit the loopback detection packets from the primary port.
The secondary port is in forwarding or blocking state when it is up. The master node receives the ring
detection packets from the secondary port and judges whether the topology of the ring network is complete. In
complete topology, the master node blocks the data packets on the secondary port, and prevents loopback
from occurring; after a link on the ring network is interrupted, the master node will open the secondary port to
forwarding the data packets.
Remarks:
A port can be set as the primary port or the secondary port of a node and it cannot be set to be both the
primary port and the secondary port.
27.1.2.11 Transit Port
The two ports for the transit node to access the Ethernet ring are both transit ports. Users can decide the role
of the two ports through configuration.
The transit port is in forwarding or pre-forwarding state when it is up. A transit port receives the control packets
from the control VLAN and at the same time forwards these packets to other ports in the control VLAN. After
the transit port resumes from the invalid state, it first enters the pre-forwarding state, receives and forwards
only the control packets, and blocks the data VLAN. After the transit node receives the notification of the aging
address table, it enters the forwarding state.
Remarks: