3com 5500-SI Manual De Usuario

544

HAPTER

26: RSTP C

ONFIGURATION

In a Switch equipped with the XRN feature, RSTP has the following characteristics:

1) Processing the whole Fabric as a node;

2) Participation of all ports except those used as Fabric ports in role selection;

3) A single root port and bridge id for the whole Fabric;

4) Distributed saving of RSTP port information

RSTP Configuration

The configuration of RSTP changes with the position of the Switch in the network, as
discussed below.

Figure 162 Configuring STP

Switch A and Switch B: Root
bridge and backup root
bridge

Switch C and Switch D:
Intermediate Switches in the
Switched network

Switch E, Switch F and Switch
G: Switches directly
connected with user PCs

Table 595 RSTP Configuration

Device

Configuration Default Value

Note

Switch A
and
Switch B

Enable the STP
feature on the
Switch

Enable the STP
feature on the
port

The STP feature is
disabled from the
Switch, but will be
enabled on all ports
once being enabled
on the Switch.

The configuration of STP feature status on
the port will not take effect if the STP
feature is disabled from the Switch.

Configure RSTP
operational
mode

The Switch works in
RSTP mode.

If there are Switches respectively running
STP and RSTP on the network, it is
recommended to set the Switch in
STP-compatible mode.

Configure the
STP-Ignore
attribute of
VLANs on a
Switch

No VLAN on a
STP-enabled Switch is
STP-Ignored.

Once a VLAN is specified to be STP-Ignored,
the packets of this VLAN will be forwarded
on any Switch port, with no restriction from
the calculated STP path.

S w itc h C

S w itc h A

S w itc h B

S w itc h D

S w itc h A

S w itc h E

S w itc h F

S w itc h G

S w itc h C

S w itc h A

S w itc h B

S w itc h D

S w itc h A

S w itc h E

S w itc h F

S w itc h G