Dell PowerSwitch S4128F-ON EMC SmartFabric OS10 User Guide Release 10.5.0 - Page 484

Non-Dell EMC hardware OS10 supports only one MST region. For a bridge to be in the same MST region as another, the following attributes must match the unique name, revision, and VLAN mapping. The default value for name is system mac. In case of Dell EMC, the user has to manually configure an unique name in all the nodes to be in a single region. If you have non-Dell EMC hardware that participates in MST, ensure these values match on all devices. A region is a combination of three unique attributes: • Name - A mnemonic string you assign to the region. The default is the system MAC address. • Revision - A 2-byte number. The default is 0. • VLAN-to-instance mapping - Placement of a VLAN in an MSTI. Region name or revision You can change the MSTP region name or revision. • Change the region name in MULTIPLE-SPANNING-TREE mode. A maximum of 32 characters. name name • Change the region revision number in MULTIPLE-SPANNING-TREE mode, from 0 to 65535, default 0. revision number Configure and verify region name OS10(conf-mstp)# name my-mstp-region OS10(conf-mstp)# do show spanning-tree mst config MST region name: my-mstp-region Revision: 0 MSTI VID 1 100 2 200-300 Modify parameters The root bridge sets the values for forward-delay, hello-time, max-age, and max-hops and overwrites the values set on other MST bridges. Forward-time Hello-time Max-age Max-hops Time an interface waits in the Discarding state and Learning state before it transitions to the Forwarding state. Interval in which the bridge sends MST BPDUs. Length of time the bridge maintains configuration information before it refreshes that information by recomputing the MST topology. A maximum number of hops a BPDU travels before a receiving device discards it. NOTE: Dell EMC recommends that only experienced network administrators change MST parameters. Poorly planned modification of MST parameters can negatively affect network performance. 1. Change the forward-time parameter in CONFIGURATION mode, from 4 to 30, default 15. spanning-tree mst forward-time seconds 2. Change the hello-time parameter in CONFIGURATION mode, from 1 to 10, default 2. Dell EMC recommends increasing the hello-time for large configurations, especially configurations with more ports. spanning-tree mst hello-time seconds 3. Change the max-age parameter in CONFIGURATION mode, from 6 to 40, default 20. spanning-tree mst max-age seconds 4. Change the max-hops parameter in CONFIGURATION mode, from 1 to 40, default 20. spanning-tree mst max-hops number 484 Layer 2