01-20-2023 04:37 PM
When I run the cli show spanning-tree vlan 1, I notice the port type is shr. What does shr stand for?
Switch#show spanning-tree vlan 1
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 32769
Address 0c21.0d37.0b00
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0c21.0d37.0b00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0 Desg FWD 4 128.1 Shr
Gi0/1 Desg FWD 4 128.2 Shr
Gi0/2 Desg FWD 4 128.3 Shr
Gi0/3 Desg FWD 4 128.4 Shr
Gi1/0 Desg FWD 4 128.5 Shr
Gi1/1 Desg FWD 4 128.6 Shr
Gi1/2 Desg FWD 4 128.7 Shr
Gi1/3 Desg FWD 4 128.8 Shr
Solved! Go to Solution.
01-21-2023 01:44 AM - edited 01-21-2023 01:46 AM
Hello
The port type in rstp is important for fast convergence (p2p/edge)
RSTP port in shared mode will negate its fast convergence, it only "assumes" its port type by the duplex mode of the physical port (H/D= stp shared, F/D=stp P2P)
Example:
The physical port could be set to F/D but the stp link type set to shared and it will show as a Shr port in stp
or
The physical port could be set th H/D but the stp link type set to point-to-point and it will show up as a P2P port in stp
So STP has no way of actually knowing what is connected to the switchport, it could be just a single host/another switch or a hub if its solely based on the duplex mode of the switchport, hence it suggested you actually set the stp port type (P2P/Edge-portfast/Shared) be it for the benefit of the network
01-20-2023 04:50 PM
Hello,
It means the port is believed to be connected to a shared segment (Shr). This could be a hub or wireless access point where multiple devices are seen or can be seen. Also if the port is operating in half-duplex the port could assume its a shard link like mentioned before of being attached to a hub or other device that operates in half-duplex.
Hope that helps
-David
01-20-2023 06:46 PM
its for Half-duplex connections.
01-21-2023 01:44 AM - edited 01-21-2023 01:46 AM
Hello
The port type in rstp is important for fast convergence (p2p/edge)
RSTP port in shared mode will negate its fast convergence, it only "assumes" its port type by the duplex mode of the physical port (H/D= stp shared, F/D=stp P2P)
Example:
The physical port could be set to F/D but the stp link type set to shared and it will show as a Shr port in stp
or
The physical port could be set th H/D but the stp link type set to point-to-point and it will show up as a P2P port in stp
So STP has no way of actually knowing what is connected to the switchport, it could be just a single host/another switch or a hub if its solely based on the duplex mode of the switchport, hence it suggested you actually set the stp port type (P2P/Edge-portfast/Shared) be it for the benefit of the network
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