Dell EMC SmartFabric OS10 User Guide Release 10.5.1

Adjust two interface parameters to increase or decrease the likelihood that a port becomes a forwarding port.

Port cost

Interface type value. The greater the port cost, the less likely the port is a forwarding port.

Port priority

Influences the likelihood that a port is selected as a forwarding port if several ports have the same port cost.

Default values for the port cost by interface:

• 100-Mb/s Ethernet interfaces — 200000
• 1-Gigabit Ethernet interfaces — 20000
• 10-Gigabit Ethernet interfaces — 2000
• Port-channel with 100 Mb/s Ethernet interfaces — 180000
• Port-channel with 1-Gigabit Ethernet interfaces — 18000
• Port-channel with 10-Gigabit Ethernet interfaces — 1800

1. Change the port cost of an interface in INTERFACE mode, from 1 to 200000000.

   spanning-tree msti number cost 1 

2. Change the port priority of an interface in INTERFACE mode, from 0 to 240 in increments of 16, default 128.

   spanning-tree msti number priority 32 

View MSTi interface configuration

OS10(conf-if-eth1/1/7)# do show spanning-tree msti 0 interface ethernet 1/1/7
ethernet1/1/7 of MSTI 0 is Designated Forwarding
Edge port: No (default)
Link type: point-to-point (auto)
Boundary: Yes, Bpdu-filter: Disable, Bpdu-Guard: Disable, Shutdown-on-Bpdu-Guard-violation: No
Root-Guard: Disable, Loop-Guard: Disable
Bpdus (MRecords) Sent: 69, Received: 0
Interface                                    Designated
Name           PortID  Prio  Cost  Sts  Cost Bridge ID         PortID
----------------------------------------------------------------------
ethernet1/1/7  0.284   0     1     FWD  0    32768  90b1.1cf4.9b8a 0.284