M A G N U M 6 K S W I T C H E S , M N S - 6 K U S E R G U I D EEven though RSTP interoperates with STP, RSTP is so much more efficient at establishing thenetwork path and the network convergence in case of a failure is very fast. For this reason,GarrettCom recommends that all your network devices be updated to support RSTP. RSTPoffers convergence times typically of less than one second. However, to make best use of RSTPand achieve the fastest possible convergence times there are some changes that you should maketo the RSTP default configuration.1. GarrettCom Inc. provides downloadable software Fault TimingAnalyzer (FTA) for testing how quickly a network recovers from a fault, oncethe redundancy feature such as STP or RSTP is configured on the switches(bridges). This software can be downloaded from the GarrettCom site. Thissoftware is available at http://www.garrettcom.com/ftaform.htm2. Under some circumstances it is possible for the rapid state transitionsemployed by RSTP to result in an increase in the rates of frame duplicationand the order in which the frames are sent and received. In order to allowRSTP switches to support applications and protocols that may be sensitive toframe duplication and out of sequence frames, RSTP may have to be explicitlyset to be compatible with STP. This explicit setting is called setting the “ForceProtocol Version” parameter to be STP compatible. This parameter should beset to all ports on a given switch3. As indicated above, one of the benefits of RSTP is the implementationof a larger range of port path costs which accommodates higher networkspeeds. New default values have also been implemented for the path costsassociated with the different network speeds. This could create incompatibilitybetween devices running the older implementations of STP a switch runningRSTP4. If you are using tagged VLANs, at least one untagged VLAN must beavailable for the BPDU’s to propagate through the network to update STPstatus5. Whenever changes are made to RSTP, it is recommended to disableand enable RSTP to ensure the changes are effectiveConfiguring RSTPThe commands to setup and configure RSTP on MNS-6K areSyntax set stp type= - Set the switch to support RSTP or change it back to STP. Need to saveand reboot the switch after this commandSyntax rstp – enter the RSTP configuration mode161
