iRBX6GF User’s Manual
UM-iRBX6GF-4.5.1-EN.docx
Pages 104 of 119
RSTP Ports
Figure 38 – RSTP Ports Interface
The following table describes the labels for the
RSTP
Ports
screen.
Label
Description
Port #
This is read-only column; R (A,B), 3, 4, 5, and 6.
Link
This is a read-only field with a value of
up
or
down
.
Enable
To disable the enabled RSTP ports, remove the box underneath to the
Enable
label.
The default is enabled (i.e. with a checkmark).
Discard BPDU
To enable the
Discard BPDU
, check the box adjacent to its label. When RSTP is off
by default,
Discard BPDU
is off (i.e. without a checkmark)
Path Cost
Enter a value for
Path Cost
. Its range is from 0 to 200000000. Its default value is 0. If
there is more than one link between two switches, the RSTP root bridge calculates
the cost of each path based on bandwidth. As per RSTP (802.1W-2004), path cost
default can be calculated by the formula:
20 Terabit / seconds [7]
Bandwidth
(in bit/second)
As seen from the formula above, the Path Cost depends on the link speed; faster link
speeds indicate smaller costs.
Priority
Enter a value for the port’s
Priority
. The port priority is in range of 0 to 240 in
increments of 16; default is 128.
P2P
Identify the
P2P
(point-to-point link); default is auto. P2P connection is a permanent
direct communication link between two parties. Other values are no /yes.
Admin Edge
Edge ports transition directly to the forwarding state, and so the protocol does not
need to wait for BPDUs to be received on edge ports. To enable initial edge state of
a port, check the box adjacent to
Admin Edge
label. Default is no (i.e. no
checkmark). Do not configure a spanning-tree instance interface as an edge port if
it is connected to any Layer 2 bridge. An instance interface connected to Layer 2
bridges but configured as an edge port can cause physical loops. [5]
Auto Edge
The auto edge feature enables automatic detection of edge devices or bridges
connected to an interface. To enable auto transition to/from the edge state, check
the box adjacent to
Auto Edge
label. Default is enabled (i.e. with a checkmark).
Role
This is a read-only column with a value of
disabled
for all bridge port roles, except
for Port 6 for which the
Role
is
designated
.
Designated
value means that Port 6 is
forwarding port for every LAN segment. Note that these values are assigned during
Configuration Factory Reset.
