User's Manual

Table Of Contents
269
Users Manual of CS-6306R
26.1.2.1 Roles of Ring’s Nodes
Each switch on an Ethernet ring is a ring node. The ring nodes are classified into master nodes and transit
nodes. Only one switch on the Ethernet ring can serve as a mere master node and other switches are worked
as transit nodes.
Master node: It positively knows whether the ring’s topology is complete, removes loopback, control other
switches to update topology information.
Transit node: It only checks the state of the local port of the ring, and notifies the master node of the invalid
link.
The role of each node can be specified by user through configuration. The thing is that each switch in the
same ring can be set to only one kind of node. In figure 1.1, switch S1 is the master node of ring network,
while switches S2, S3 and S4 are transit nodes.
26.1.2.2 Role of the Ring’s Port
EAPS demands each switch has two ports to connect the ring network. Each port of the ring network also
needs to be specified through configuration and the protocol supports the following kinds of port roles:
Primary port: the primary port can be configured only on the master node. The master node transmits the ring
detection packets through the primary port.
Secondary port: the secondary port can be configured only on the master node. 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.
Transit port: the transmit port can only be configured on the transit node. Both ports through which the transit
node connects the ring network are all transit ports.
Each port of the ring network can be configured as only one port role after the node's role of the switch and
the control VLAN are configured. As shown in figure 1.1, the port through which master node S1 connects
transit node S4 is a primary port, the port through which S1 connects S2 is a secondary port, and the ports
through which other switches connect the ring network are all transit ports.
Remark:
To configure a same switch to belong to multiple rings, the switch must connect different rings through
different physical ports.