STRIDE SE-MC2U-SC, User Manual

Page: 101 / 230

Recovery Time, Hops and Convergence:
The typical RSTP recovery time (time to start forwarding messages on the backup port) on a
link-loss failure is <50ms per “hop”. A hop is defined as a link between two switches. A link
to an end station is not considered a hop.
The Max Age setting controls how long RSTP messages may circulate in the network. Since
the largest value allowed for Max Age is 40, the largest RSTP network hop-diameter is also
40.
See the RSTP Examples topic in this section for a more detailed explanation about hops and
recovery time.
The time it takes for all of the switches to have a stable configuration and send network
traffic is called the convergence time. STP was developed when it was acceptable to have
a convergence time of maybe a minute or more, but that is not the case anymore. Due to
the increased demand for better convergence times, Rapid Spanning Tree Protocol was
developed, bringing the normal convergence time for a properly configured network down
to a few seconds. The RSTP takes advantage of the fact that most modern Ethernet links
between switches are point-to-point connections. With a point-to-point link, the switches
can quickly decide if the link should be active or not.
4-17
Chapter 4 - Managed Switch Software Setup
Stride Industrial Ethernet Switches User Manual 2nd Ed. Rev. A