60 Dell Converged Enhanced Ethernet Administrator’s Guide53-1002116-01Configuring STP, RSTP, or MSTP on CEE interface ports6Guard root protects the root bridge from malicious attacks and unintentional misconfigurationswhere a bridge device that is not intended to be the root bridge becomes the root bridge. Thiscauses severe bottlenecks in the data path. Guard root ensures that the port on which it is enabledis a designated port. If the guard root-enabled port receives a superior BPDU, it goes to adiscarding state.To enable the guard root on a CEE interface, perform the following steps from Privileged EXECmode.1. Enter the configure terminal command to access global configuration mode.2. Enter the interface command to specify the CEE interface type and slot/port number.switch(config)#interface intengigabitethernet 0/13. Enter the no shutdown command to enable the CEE interface.4. Enter the spanning-tree command to enable the guard root on a CEE interface.switch(conf-if-te-0/1)#spanning-tree guard rootSpecifying the MSTP hello timeFrom the CEE interface, use this command to set the time interval between BPDUs sent by the rootswitch. Changing the hello-time affects all spanning tree instances.The max-age setting must be greater than the hello-time setting (see “Specifying the bridgemaximum aging time” on page 53). The range is 1 through 10 seconds. The default is 2 seconds.To specify the MSTP hello time on a CEE interface, perform the following steps from Privileged EXECmode.1. Enter the configure terminal command to access global configuration mode.2. Enter the interface command to specify the CEE interface type and slot/port number.switch(config)#interface intengigabitethernet 0/13. Enter the no shutdown command to enable the CEE interface.4. Enter the spanning-tree command to specify the hello time on a CEE interface.switch(conf-if-te-0/1)#spanning-tree hello-time 5Specifying restrictions for an MSTP instanceFrom the CEE interface, use this command to specify restrictions on the interface for an MSTPinstance.To specify restrictions for an MSTP instance on a CEE interface, perform the following steps.1. Enter the configure terminal command to access global configuration mode from PrivilegedEXEC mode.2. Enter the interface command to specify the CEE interface type and slot/port number.switch(config)#interface intengigabitethernet 0/13. Enter the no shutdown command to enable the CEE interface.
