Spanning port types in Nexus switches

1.     Edge port :-

Switchport configured as edge ports when it is connected to end host devices. It can be enabled on access or trunk port.

Sometimes there is a requirement to transition the trunk port, e.g port connected to server running ESXi, immediately in forwarding state without going to the various spanning tree states (listening, learning etc..).Edge port feature can be used in such scenarios.

It is similar to the portfast feature in Legacy switchport.

Always configure the port as edge port with cautious as it can create Layer 2 loops if not correctly configured specially when it is enabled on switchport connected to  other switch or bridge.

configuration..

It can be enabled globally as shown in below command.

Note:- BY default switchport is configured as normal.

Switch(config)# spanning-tree port type edge default

It can also be enabled per port.

switch(config)# interface ethernet 1/1 switch(config-if)#  spanning-tree port type edge

2. Network Port:-

Switchport connected to other switches and bridges via point to point link should be configured as network port. 

It can be enable per interface basis we well as in global mode.

switch(config)# interface ethernet 1/4 switch(config-if)# spanning-tree port type network

switch# configure terminal switch(config)# spanning-tree port type network default

As soon as we configure network port, it enables the bridge assurance.

Bridge assurance is used to prevent uni direction link. Port on which bridge assurance is configured, send BPDU no matter it is in alternate and backup port. It the port didn't receive BPDU from other end it will move in blocking state and will resume the running state when it start receiving the BPDUs.

       If network port is configured on the switchport connected to a host, it will move it to blocking state as it will not receive the BPDU from host machine.

3.     Normal port :-

Switchport which will go through all STP stages. It is the default switchport state.

Switchport connected to switchport or bridge is configured as normal port. One exception is VPC peer link which is configured by default as network port.

Note:-

a.     Configure all access and trunk ports connected to hosts as edge ports.

b.     Bridge Assurance runs only on point-to-point spanning tree network ports. You must configure each side of the link for this feature.