Contemporary Control Systems Compact Managed Switches Software Manual for Web Browser User Manual

Page 57

TD020851-0MG

STP State may report any of three states:
Forwarding indicates the RSTP port is up and actively participating in the tree — that is,

it is not currently a backup or alternate port. The port forwards frames, and

continues to learn new addresses. If RSTP is

disabled as in Figure 53, each

port is reported to be in the Forwarding state (whether the port is Up or Down) — but

this has no meaning since the tree is disabled.

Learning is the brief port state (as it begins to learn addresses) before its forwarding

delay expires. Actually, this state is rarely reported on screen, but could be if you

happen to refresh the monitor screen while a port is transitioning from Discarding

to Forwarding. The Learning state only occurs as the tree is being restructured.

Discarding is reported if the port is not active in the tree. The port receives STP frames,

but it does not forward frames. If the tree is stable and port states are consistent

throughout the network, every root port and designated port will quickly transition

through its Learning state to the Forwarding state. At the same time, all alternate

and backup ports will stay in the Discarding state since they are not active in the

tree — as is the case in Figure 47 with port 5, which is Up but not active.

Only RSTP port states (which superseded STP states) are shown in the monitor screen.

If you wish to compare the port states of RSTP versus STP, refer to Table 2.

Table 2 — STP & RSTP Port States Compared

The

Link Status column of the Monitor STP Port Status screen simply reports if a port

is Up or Down. The

Port Speed/Duplex column reports the data rate and duplex state

of any port that is up — but displays no information for any port that is down. These last

two columns report their information even if the RSTP/STP function is disabled — as is

the case in Figure 48.
Note that for a port to be in the Forwarding state with RSTP enabled, its port must be Up.

This manual is related to the following products: