Viewing Global Statistics For Stp - Siemens RUGGEDCOM ROS v4.3 User Manual

RUGGEDCOM ROS
User Guide
Parameter
IEEE802.1w Interoperability
Cost Style
3. Click Apply.
Section 5.2.7

Viewing Global Statistics for STP

To view global statistics for STP, navigate to Spanning Tree » View Bridge RSTP Statistics . The Bridge RSTP
Statistics form appears.
Viewing Global Statistics for STP
Description
These are the supported configuration options:
• Off - Fast Root Failover algorithm is disabled and hence a root
switch failure may result in excessive connectivity recovery
time.
• On - Fast Root Failover is enabled and the most robust
algorithm is used, which requires the appropriate support in the
root switch.
• On with standard root - Fast Root Failover is enabled but a
"relaxed" algorithm is used, allowing the use of a standard
switch in the root role.
Synopsis: { On, Off }
Default: On
The original RSTP protocol defined in the IEEE 802.1w standard
has minor differences from more recent, enhanced, standard(s).
Those differences cause interoperability issues which, although
they do not completely break RSTP operation, can lead to a longer
recovery time from failures in the network.
eRSTP offers some enhancements to the protocol which make the
switch fully interoperable with other vendors' switches, which
may be running IEEE 802.2w RSTP. The enhancements do not
affect interoperability with more recent RSTP editions.
This configuration parameter enables the aforementioned
interoperability mode.
Synopsis: { STP (16 bit), RSTP (32 bit) }
Default: STP (16 bit)
The RSTP standard defines two styles of a path cost value. STP
uses 16-bit path costs based upon 1x10E9/link speed (4 for
1Gbps, 19 for 100 Mbps and 100 for 10 Mbps) whereas RSTP
uses 32-bit costs based upon 2x10E13/link speed (20,000 for
1Gbps, 200,000 for 100 Mbps and 2,000,000 for 10 Mbps).
However, switches from some vendors keep using the STP path
cost style even in RSTP mode, which can cause confusion and
interoperability problems.
This configuration parameter selects the style of link costs to
employ.
Note that RSTP link costs are used only when the bridge version
support is set to allow RSTP and the port does not migrate to STP.
Chapter 5
Setup and Configuration
169