Device Type : DGS-1210-20/ME
MAC Address : A8-63-7D-49-99-80
IP Address : 10.90.90.90 (Manual)
VLAN Name : default
Subnet Mask : 255.0.0.0
Default Gateway : 10.98.50.1
System Boot Version : 1.00.023
System Firmware Version : 6.13.B010
System Hardware Version : A1
System Serial Number : TM3T113000641
System Name :
System Location :
System up time : 0 days, 1 hrs, 49 min, 30 secs
System Contact :
System Time : 01/01/2016 01:49:06
STP : Enabled
GVRP : Disabled
IGMP Snooping : Disabled
VLAN Trunk : Disabled
802.1X Status : Disabled
Telnet : Enabled (TCP 23)
Web : Enabled (TCP 80)
RMON : Disabled
SSH : Disabled
Syslog Global State : Disabled
SSL : Disabled
CLI Paging : Enabled
Password Encryption State : Disabled

Command: show stp instance

[spoiler]STP Bridge Global Settings
------------------------------
STP Status : Enabled
STP Version : RSTP
Bridge Priority : 4096
Max Age : 20
Hello Time : 2
Forward Delay : 15
TX Hold Count : 6
Max Hops : 20
Forward BPDU : Enabled
NNI BPDU Address : dot1d
Root Cost : 0
Root Maximum Age : 20
Root Forward Delay : 15
Root Port : 0
Root Bridge : 10:00:A8:63:7D:49:99:80

## CIST
Designated Root Bridge a8:63:7d:49:99:80 Priority 4096
We are the Root for CST
Port 0 , path cost 0
Regional Root Bridge a8:63:7d:49:99:80 Priority 4096
Path cost 0
Designated Bridge a8:63:7d:49:99:80 Priority 4096
Configured Forward delay 15, Max age 20, Max hops 20
Operational Forward delay 15, Max age 20
Topology Changes Count : 163
Last Topology Change : 47

Interface Role Sts Cost Prio.Nbr Type
--------- ---- --- ---- -------- ----
10 Designated Forwarding 200000 128.10 Point to point
13 Designated Forwarding 20000 128.13 Point to point
14 Designated Forwarding 20000 128.14 Point to point
15 Designated Forwarding 20000 128.15 Point to point
16 Designated Forwarding 20000 128.16 Point to pointt

Command: show stp


STP Bridge Global Settings
------------------------------
STP Status : Enabled
STP Version : RSTP
Bridge Priority : 32768
Max Age : 20
Hello Time : 2
Forward Delay : 15
TX Hold Count : 6
Max Hops : 20
Forward BPDU : Enabled
NNI BPDU Address : dot1d
Root Cost : 200
Root Maximum Age : 20
Root Forward Delay : 15
Root Port : 15
Root Bridge : 10:00:A8:63:7D:49:99:80

Command: show stp instance


## CIST
Designated Root Bridge a8:63:7d:49:99:80 Priority 4096
Port 15 , path cost 200
Regional Root Bridge a8:63:7d:49:99:c0 Priority 32768
Path cost 0
Designated Bridge a8:63:7d:49:99:80 Priority 4096
Configured Forward delay 15, Max age 20, Max hops 20
Operational Forward delay 15, Max age 20
Topology Changes Count : 234
Last Topology Change : 71

Interface Role Sts Cost Prio.Nbr Type
--------- ---- --- ---- -------- ----
15 Root Forwarding 200 128.15 Point to point
16 Designated Forwarding 200 128.16 Point to point

STP Bridge Global Settings
------------------------------
STP Status : Enabled
STP Version : RSTP
Bridge Priority : 32768
Max Age : 20
Hello Time : 2
Forward Delay : 15
TX Hold Count : 6
Max Hops : 20
Forward BPDU : Enabled
NNI BPDU Address : dot1d
Root Cost : 200
Root Maximum Age : 20
Root Forward Delay : 15
Root Port : 16
Root Bridge : 10:00:A8:63:7D:49:99:80

sw3:5# show stp instance
Command: show stp instance


## CIST
Designated Root Bridge a8:63:7d:49:99:80 Priority 4096
Port 16 , path cost 200
Regional Root Bridge a8:63:7d:49:99:e0 Priority 32768
Path cost 0
Designated Bridge a8:63:7d:49:99:80 Priority 4096
Configured Forward delay 15, Max age 20, Max hops 20
Operational Forward delay 15, Max age 20
Topology Changes Count : 106
Last Topology Change : 1076

Interface Role Sts Cost Prio.Nbr Type
--------- ---- --- ---- -------- ----
15 Alternate Discarding 200 128.15 Point to point
16 Root Forwarding 200 128.16 Point to point

Router#sh running-config
Building configuration...

Current configuration : 1691 bytes
!
! Last configuration change at 14:13:43 UTC Mon Aug 2 2021
!
version 15.8
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
no logging console
!
no aaa new-model
errdisable recovery cause udld
errdisable recovery cause bpduguard
errdisable recovery cause rootguard
errdisable recovery cause pagp-flap
errdisable recovery cause dtp-flap
errdisable recovery cause link-flap
errdisable recovery interval 86400
!
!
!
!
!
prompt config hostname-length 50
no ip source-route
!
!
!
!
!
!
no ip bootp server
no ip domain lookup
ip cef
no ipv6 cef
multilink bundle-name authenticated
!
!
!
license udi pid C921-4P sn PSZ24321HX7
!
!
!
spanning-tree uplinkfast max-update-rate 200
spanning-tree uplinkfast
spanning-tree backbonefast
spanning-tree vlan 1 priority 16384
no spanning-tree vlan 3
no spanning-tree vlan 33
!
redundancy
!
lldp run
!
!
!
!
!
interface GigabitEthernet0
no ip address
!
interface GigabitEthernet1
no ip address
!
interface GigabitEthernet2
switchport mode access
no ip address
!
interface GigabitEthernet3
switchport mode access
no ip address
!
interface GigabitEthernet4
no ip address
shutdown
duplex auto
speed auto
!
interface GigabitEthernet5
no ip address
shutdown
duplex auto
speed auto
!
interface Vlan1
no ip address
shutdown
!
interface Vlan33
ip address 10.98.50.15 255.255.255.0
!
ip default-gateway 10.98.50.1
no ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
line con 0
line vty 0 4
login
transport input none
!
scheduler process-watchdog hang
scheduler allocate 20000 1000
!
end

Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
GigabitEthernet0 128.1 128 3004 FWD 3004 16384 0f3c.bed0.0000 128.1
GigabitEthernet2 128.3 128 3004 FWD 0 4096 a863.7d49.9980 128.13
GigabitEthernet3 128.4 128 3004 BLK 0 4096 a863.7d49.9980 128.15