tech:network:cisco:stp:loopguard:loopguard
Table of Contents
STP: Loop Guard
Topology
Log
- loopguard verification is difficult…
- loopguard, rootguard can configure exclusively. when loopguard enabled default, roop guard configuration works in Catalyst 2960 15.x.
SW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW1(config)#spa
SW1(config)#spann
SW1(config)#spanning-tree loopgu
SW1(config)#spanning-tree loopguard defa
SW1(config)#spanning-tree loopguard default
SW1(config)#^Z
SW1#
*Mar 1 09:01:55.258: %SYS-5-CONFIG_I: Configured from console by console
SW1#
*Mar 1 09:03:51.868: STP: VLAN0001 Topology Change rcvd on Fa1/0/1
*Mar 1 09:03:51.885: STP: VLAN0001 we are the spanning tree root
*Mar 1 09:03:51.885: STP[1]: Generating TC trap for port FastEthernet1/0/2
SW1#
*Mar 1 09:03:52.892: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/2, changed state to down
*Mar 1 09:03:53.898: %LINK-3-UPDOWN: Interface FastEthernet1/0/2, changed state to down
SW1#
*Mar 1 09:05:43.772: set portid: VLAN0001 Fa1/0/2: new port id 8004
*Mar 1 09:05:43.772: STP: VLAN0001 Fa1/0/2 -> listening
SW1#
*Mar 1 09:05:45.769: %LINK-3-UPDOWN: Interface FastEthernet1/0/2, changed state to up
*Mar 1 09:05:46.775: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/2, changed state to up
SW1#
*Mar 1 09:05:58.779: STP: VLAN0001 Fa1/0/2 -> learning
SW1#
*Mar 1 09:06:13.745: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
*Mar 1 09:06:13.770: STP: VLAN0001 Topology Change rcvd on Fa1/0/1
*Mar 1 09:06:13.787: STP[1]: Generating TC trap for port FastEthernet1/0/2
*Mar 1 09:06:13.787: STP: VLAN0001 Fa1/0/2 -> forwarding
*Mar 1 09:06:13.812: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1#
*Mar 1 09:06:37.770: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1#
*Mar 1 09:07:28.655: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1#
*Mar 1 09:08:47.810: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1#sh spa
SW1#sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 8193
Address e8ed.f315.9380
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 8193 (priority 8192 sys-id-ext 1)
Address e8ed.f315.9380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa1/0/1 Desg FWD 19 128.3 P2p
Fa1/0/2 Desg FWD 19 128.4 P2p
SW1#
*Mar 1 09:09:16.826: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW1(config)#do sh ip int vlan 1
Vlan1 is up, line protocol is up
Internet address is 172.16.0.11/24
Broadcast address is 255.255.255.255
Address determined by setup command
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is enabled
IP Flow switching is disabled
IP CEF switching is enabled
IP CEF switching turbo vector
IP Null turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
SW1(config)#
*Mar 1 09:11:23.377: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1(config)#
*Mar 1 09:13:10.591: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1(config)#
*Mar 1 09:13:39.608: STP: VLAN0001 Topology Change rcvd on Fa1/0/2
SW1(config)#
*Mar 1 09:15:30.245: STP: VLAN0001 heard root 1-0026.ca6b.e980 on Fa1/0/2
*Mar 1 09:15:30.245: supersedes 8193-e8ed.f315.9380
*Mar 1 09:15:30.245: STP: VLAN0001 new root is 1, 0026.ca6b.e980 on port Fa1/0/2, cost 38
SW1(config)#
*Mar 1 09:16:59.475: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/2
SW1(config)#
*Mar 1 09:17:00.557: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/2
SW1(config)#
*Mar 1 09:17:02.562: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/2
SW1(config)#
*Mar 1 09:17:04.567: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/2
SW1(config)#
*Mar 1 09:17:06.571: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/2
SW1(config)#conf t
^
% Invalid input detected at '^' marker.
SW1(config)#spa
SW1(config)#spanning-tree loop
SW1(config)#spanning-tree loopguard defa
SW1(config)#no spanning-tree loopguard default
SW1(config)#spa
SW1(config)#int range f1/0/1-2
SW1(config-if-range)#spa
SW1(config-if-range)#spanning-tree gu
SW1(config-if-range)#spanning-tree guard lo
SW1(config-if-range)#spanning-tree guard loop
SW1(config-if-range)#^Z
SW1#
*Mar 1 09:21:01.947: %SYS-5-CONFIG_I: Configured from console by console
SW1#sh spa
SW1#sh spanning-tree vlan 1
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
Cost 38
Port 4 (FastEthernet1/0/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 8193 (priority 8192 sys-id-ext 1)
Address e8ed.f315.9380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa1/0/1 Desg FWD 19 128.3 P2p
Fa1/0/2 Root FWD 19 128.4 P2p
SW1#
SW2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW2(config)#spa
SW2(config)#spanning-tree loo
SW2(config)#spanning-tree loopguard defa
SW2(config)#spanning-tree loopguard default
SW2(config)#spa
SW2(config)#spanning-tree rootgu
SW2(config)#spanning-tree rootgua
SW2(config)#spanning-tree root
SW2(config)#spanning-tree roo
SW2(config)#spanning-tree roo
SW2(config)#spanning-tree gua
SW2(config)#spanning-tree por
SW2(config)#spanning-tree portfast gur
SW2(config)#spanning-tree portfast gua
SW2(config)#spanning-tree portfast roo
SW2(config)#spanning-tree portfast roogu
SW2(config)#spanning-tree portfast ?
bpdufilter Enable portfast bpdu filter on this switch
bpduguard Enable portfast bpdu guard on this switch
default Enable portfast by default on all access ports
SW2(config)#spanning-tree gu
SW2(config)#spanning-tree gur
SW2(config)#spanning-tree gua
SW2(config)#spanning-tree ro
SW2(config)#spanning-tree lo
SW2(config)#spanning-tree lo
SW2(config)#spanning-tree l
SW2(config)#spanning-tree loo
SW2(config)#spanning-tree rootgu
SW2(config)#spanning-tree rootgu
SW2(config)#spanning-tree rootgu
SW2(config)#spanning-tree guard
*Mar 1 08:58:10.553: set portid: VLAN0001 Fa1/0/1: new port id 8003
*Mar 1 08:58:10.553: STP: VLAN0001 Fa1/0/1 -> listening
SW2(config)#spanning-tree guard loot
*Mar 1 08:58:12.549: %LINK-3-UPDOWN: Interface FastEthernet1/0/1, changed state to up
*Mar 1 08:58:13.556: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/1, changed state to up
SW2(config)#spanning-tree guard root
^
% Invalid input detected at '^' marker.
SW2(config)#
*Mar 1 08:58:25.560: STP: VLAN0001 Fa1/0/1 -> learning
SW2(config)#int f1/0/1
*Mar 1 08:58:40.567: STP[1]: Generating TC trap for port FastEthernet1/0/1
*Mar 1 08:58:40.567: STP: VLAN0001 sent Topology Change Notice on Fa1/0/2
*Mar 1 08:58:40.567: STP: VLAN0001 Fa1/0/1 -> forwarding
SW2(config)#int f1/0/3
SW2(config-if)#spa
SW2(config-if)#spanning-tree gu
SW2(config-if)#spanning-tree guard ro
SW2(config-if)#spanning-tree guard root
SW2(config-if)#no spanning-tree guard root
SW2(config-if)#exit
SW2(config)#no spa
SW2(config)#no spanning-tree loop
SW2(config)#no spanning-tree loopguard defau
SW2(config)#no spanning-tree loopguard default
SW2(config)#int f1/0/3
SW2(config-if)#spa
SW2(config-if)#spanning-tree gu
SW2(config-if)#spanning-tree guard ro
SW2(config-if)#spanning-tree guard root
SW2(config-if)#sp
SW2(config-if)#spa
SW2(config-if)#spanning-tree gua
SW2(config-if)#spanning-tree guard loo
SW2(config-if)#spanning-tree guard loop
SW2(config-if)#no spanning-tree guard loop
SW2(config-if)#^Z
SW2#
*Mar 1 09:01:11.788: %SYS-5-CONFIG_I: Configured from console by console
SW2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW2(config)#spa
SW2(config)#spa
SW2(config)#spanning-tree loop
SW2(config)#spanning-tree loopguard defau
SW2(config)#spanning-tree loopguard default
SW2(config)#^Z
SW2#
*Mar 1 09:01:54.419: %SYS-5-CONFIG_I: Configured from console by console
SW2#
*Mar 1 09:03:51.029: STP: VLAN0001 sent Topology Change Notice on Fa1/0/2
*Mar 1 09:03:51.029: STP[1]: Generating TC trap for port FastEthernet1/0/1
*Mar 1 09:03:52.036: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/1, changed state to down
SW2#
*Mar 1 09:03:53.043: %LINK-3-UPDOWN: Interface FastEthernet1/0/1, changed state to down
SW2#
*Mar 1 09:05:42.917: set portid: VLAN0001 Fa1/0/1: new port id 8003
*Mar 1 09:05:42.917: STP: VLAN0001 Fa1/0/1 -> listening
SW2#
*Mar 1 09:05:44.913: %LINK-3-UPDOWN: Interface FastEthernet1/0/1, changed state to up
*Mar 1 09:05:45.920: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/1, changed state to up
SW2#
*Mar 1 09:05:57.924: STP: VLAN0001 Fa1/0/1 -> learning
SW2#
*Mar 1 09:06:12.931: STP[1]: Generating TC trap for port FastEthernet1/0/1
*Mar 1 09:06:12.931: STP: VLAN0001 sent Topology Change Notice on Fa1/0/2
*Mar 1 09:06:12.931: STP: VLAN0001 Fa1/0/1 -> forwarding
SW2#
*Mar 1 09:15:29.406: STP: VLAN0001 heard root 1-0026.ca6b.e980 on Fa1/0/1
*Mar 1 09:15:29.406: supersedes 8193-e8ed.f315.9380
*Mar 1 09:15:29.406: STP: VLAN0001 new root is 1, 0026.ca6b.e980 on port Fa1/0/1, cost 38
*Mar 1 09:15:29.842: STP: VLAN0001 sent Topology Change Notice on Fa1/0/1
*Mar 1 09:15:29.842: STP[1]: Generating TC trap for port FastEthernet1/0/2
*Mar 1 09:15:29.842: STP: VLAN0001 Fa1/0/2 -> blocking
SW2#
*Mar 1 09:16:58.636: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/1
SW2#
*Mar 1 09:16:59.718: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/1
SW2#
*Mar 1 09:17:01.723: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/1
SW2#
*Mar 1 09:17:03.728: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/1
SW2#
*Mar 1 09:17:05.733: STP: VLAN0001 heard root 32769-0022.bd89.2180 on Fa1/0/1
SW2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW2(config)#spa
SW2(config)#spanning-tree loop
SW2(config)#spanning-tree loopguard defau
SW2(config)#no spanning-tree loopguard default
SW2(config)#int range f1/0/1-2
SW2(config-if-range)#spa
SW2(config-if-range)#spanning-tree gu
SW2(config-if-range)#spanning-tree guard lo
SW2(config-if-range)#spanning-tree guard loop
SW2(config-if-range)#^Z
SW2#
*Mar 1 09:21:02.082: %SYS-5-CONFIG_I: Configured from console by console
SW2#
ASW1#sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 8193
Address e8ed.f315.9380
Cost 19
Port 1 (FastEthernet0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0022.bd89.2180
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Root LRN 19 128.1 P2p
Fa0/2 Altn BLK 19 128.2 P2p
Fa0/3 Desg LIS 19 128.3 P2p
Fa0/8 Desg LRN 19 128.8 P2p
ASW1#sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 8193
Address e8ed.f315.9380
Cost 19
Port 1 (FastEthernet0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0022.bd89.2180
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Root FWD 19 128.1 P2p
Fa0/2 Altn BLK 19 128.2 P2p
Fa0/3 Desg LIS 19 128.3 P2p
Fa0/8 Desg FWD 19 128.8 P2p
ASW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
ASW1(config)#spa
ASW1(config)#spanning-tree loop
ASW1(config)#spanning-tree loopguard defa
ASW1(config)#spanning-tree loopguard default
ASW1(config)#int f0/3
ASW1(config-if)#swi
ASW1(config-if)#spa
ASW1(config-if)#spanning-tree guar
ASW1(config-if)#spanning-tree guard roo
ASW1(config-if)#spanning-tree guard root
ASW1(config-if)#
*Mar 1 00:02:01.584: %SPANTREE-2-ROOTGUARD_CONFIG_CHANGE: Root guard enabled on port FastEthernet0/3.
ASW1(config-if)#
*Mar 1 00:02:27.631: %SPANTREE-2-ROOTGUARD_BLOCK: Root guard blocking port FastEthernet0/3 on VLAN0001.
ASW1(config-if)#sh sp
ASW1(config-if)#^Z
ASW1#sh spa
ASW1#sh spanning-tree
*Mar 1 00:03:39.764: %SYS-5-CONFIG_I: Configured from console by console
ASW1#sh spanning-tree inco
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#
*Mar 1 00:03:45.787: %SPANTREE-2-ROOTGUARD_UNBLOCK: Root guard unblocking port FastEthernet0/3 on VLAN0001.
ASW1#
*Mar 1 00:06:22.344: %SPANTREE-2-ROOTGUARD_BLOCK: Root guard blocking port FastEthernet0/3 on VLAN0001.
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
VLAN0001 FastEthernet0/3 Root Inconsistent
Number of inconsistent ports (segments) in the system : 1
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
Number of inconsistent ports (segments) in the system : 0
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
Number of inconsistent ports (segments) in the system : 0
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
Number of inconsistent ports (segments) in the system : 0
ASW1#
*Mar 1 00:08:08.569: %SPANTREE-2-ROOTGUARD_UNBLOCK: Root guard unblocking port FastEthernet0/3 on VLAN0001.
ASW1#sh spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ------------------------ ------------------
Number of inconsistent ports (segments) in the system : 0
ASW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
ASW1(config)#int f0/3
ASW1(config-if)#no spa
ASW1(config-if)#no spanning-tree root
ASW1(config-if)#no spanning-tree gua
ASW1(config-if)#no spanning-tree guard ro
ASW1(config-if)#no spanning-tree rootgu
ASW1(config-if)#spa
ASW1(config-if)#spanning-tree roo
ASW1(config-if)#spanning-tree gua
ASW1(config-if)#spanning-tree guard ro
ASW1(config-if)#no spanning-tree guard root
ASW1(config-if)#
*Mar 1 00:09:18.295: %SPANTREE-2-ROOTGUARD_CONFIG_CHANGE: Root guard disabled on port FastEthernet0/3.
ASW1(config-if)#do sh spa
ASW1(config-if)#do sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
Cost 19
Port 3 (FastEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0022.bd89.2180
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Desg LRN 19 128.2 P2p
Fa0/3 Root FWD 19 128.3 P2p
Fa0/8 Desg FWD 19 128.8 P2p
ASW1(config-if)#do sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
Cost 19
Port 3 (FastEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0022.bd89.2180
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Desg LRN 19 128.2 P2p
Fa0/3 Root FWD 19 128.3 P2p
Fa0/8 Desg FWD 19 128.8 P2p
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 98
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 99
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 100
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 101
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 101
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 102
ASW1(config-if)#do sh spanning-tree int f0/3 detail
Port 3 (FastEthernet0/3) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 1, address 0026.ca6b.e980
Designated bridge has priority 1, address 0026.ca6b.e980
Designated port id is 128.1, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
Loop guard is enabled by default on the port
BPDU: sent 201, received 103
ASW1(config-if)#do sh span
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
Cost 19
Port 3 (FastEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0022.bd89.2180
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Desg FWD 19 128.2 P2p
Fa0/3 Root FWD 19 128.3 P2p
Fa0/8 Desg FWD 19 128.8 P2p
ASW1(config-if)#
*Mar 1 00:11:58.534: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to down
ASW1(config-if)#
*Mar 1 00:11:59.532: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to down
ASW1(config-if)#
*Mar 1 00:12:05.732: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to up
*Mar 1 00:12:06.738: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to up
ASW1(config-if)#do sh spann
ASW1(config-if)#do sh spann
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
Cost 19
Port 3 (FastEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0022.bd89.2180
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Desg FWD 19 128.2 P2p
Fa0/3 Root FWD 19 128.3 P2p
Fa0/8 Desg FWD 19 128.8 P2p
ASW1(config-if)#conf t
^
% Invalid input detected at '^' marker.
ASW1(config-if)#exit
ASW1(config)#spa
ASW1(config)#spanning-tree loop
ASW1(config)#spanning-tree loopguard defau
ASW1(config)#spanning-tree loopguard default
ASW1(config)#spa
ASW1(config)#spa
ASW1(config)#int range f0/1-2 spa
ASW1(config)#int range f0/1-2
ASW1(config-if-range)#spa
ASW1(config-if-range)#spanning-tree gu
ASW1(config-if-range)#spanning-tree guard loo
ASW1(config-if-range)#spanning-tree guard loop
ASW1(config-if-range)#^Z
ASW1#
*Mar 1 00:15:58.264: %SYS-5-CONFIG_I: Configured from console by console
ASW1#
ASW2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
ASW2(config)#
ASW2(config)#
ASW2(config)#
ASW2(config)#
ASW2(config)#
ASW2(config)#
ASW2(config)#
ASW2(config)#spa
ASW2(config)#spanning-tree pri
ASW2(config)#spanning-tree vlan 1 pri
ASW2(config)#spanning-tree vlan 1 priority 0
ASW2(config)#int vlan 1
ASW2(config-if)#ip address 172.16.0.22 255.255.255.0
ASW2(config-if)#no shut
ASW2(config-if)#e
*Mar 1 00:03:04.205: %LINK-3-UPDOWN: Interface Vlan1, changed state to up
ASW2(config-if)#exit
ASW2(config)#
*Mar 1 00:03:04.213: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
ASW2(config)#spa
ASW2(config)#spanning-tree vla
ASW2(config)#spanning-tree vlan 1 pri
ASW2(config)#no spanning-tree vlan 1 priority
ASW2(config)#do sh spa
ASW2(config)#do sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 8193
Address e8ed.f315.9380
Cost 38
Port 1 (FastEthernet0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0026.ca6b.e980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Root FWD 19 128.1 P2p
ASW2(config)#do sh spanning-tree int f0/1
Vlan Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
VLAN0001 Root FWD 19 128.1 P2p
ASW2(config)#do sh spanning-tree int f0/1 deta
Port 1 (FastEthernet0/1) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.1.
Designated root has priority 8193, address e8ed.f315.9380
Designated bridge has priority 32769, address 0022.bd89.2180
Designated port id is 128.3, designated path cost 19
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
BPDU: sent 33, received 67
ASW2(config)#do sh spanning-tree int f0/1 deta
Port 1 (FastEthernet0/1) of VLAN0001 is root forwarding
Port path cost 19, Port priority 128, Port Identifier 128.1.
Designated root has priority 8193, address e8ed.f315.9380
Designated bridge has priority 32769, address 0022.bd89.2180
Designated port id is 128.3, designated path cost 19
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
BPDU: sent 33, received 68
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 33, received 71
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 33, received 71
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 33, received 71
ASW2(config)#do ping 172.16.0.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 1/2/8 ms
ASW2(config)#do ping 172.16.0.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/5/9 ms
ASW2(config)#do ping 172.16.0.11 repeat 1000000
Type escape sequence to abort.
Sending 1000000, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!.
Success rate is 99 percent (912/913), round-trip min/avg/max = 1/3/33 ms
ASW2(config)#spa
ASW2(config)#spanning-tree vla
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 33, received 117
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 33, received 119
ASW2(config)#spa
ASW2(config)#spanning-tree vla
ASW2(config)#spanning-tree vlan 1 pri
ASW2(config)#spanning-tree vlan 1 priority 0
ASW2(config)#spanning-tree vlan 1 priority 0
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 34, received 125
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 35, received 125
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 35, received 125
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 49, received 125
ASW2(config)#do sh spanning-tree int f0/1 deta | i BPDU
BPDU: sent 49, received 125
ASW2(config)#sh spa
ASW2(config)#sh spann
ASW2(config)#do sh spa
ASW2(config)#do sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 1 (priority 0 sys-id-ext 1)
Address 0026.ca6b.e980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
ASW2(config)#do ping 172.16.0.11 repeat 1000000
Type escape sequence to abort.
Sending 1000000, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
......
Success rate is 0 percent (0/6)
ASW2(config)#no spa
ASW2(config)#no spanning-tree vla
ASW2(config)#no spanning-tree vlan 1 pri
ASW2(config)#no spanning-tree vlan 1 priority
ASW2(config)#do ping 172.16.0.11 repeat 1000000
Type escape sequence to abort.
Sending 1000000, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
........................!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.
Success rate is 95 percent (570/595), round-trip min/avg/max = 1/3/33 ms
ASW2(config)#do ping 172.16.0.11 repeat 1000000
Type escape sequence to abort.
Sending 1000000, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (804/804), round-trip min/avg/max = 1/4/42 ms
ASW2(config)#sh spa
ASW2(config)#spa
ASW2(config)#spanning-tree vlan 1 pri
ASW2(config)#spanning-tree vlan 1 priority 0
ASW2(config)#
*Mar 1 00:11:41.027: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
*Mar 1 00:11:42.025: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down
ASW2(config)#
*Mar 1 00:11:43.024: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down
ASW2(config)#
*Mar 1 00:11:49.256: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
*Mar 1 00:11:50.263: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
ASW2(config)#^Z
ASW2#sh spa
ASW2#sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 1 (priority 0 sys-id-ext 1)
Address 0026.ca6b.e980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
-------------------
*Mar 1 00:12:13.43 ---- --- --------- -------- --------------------------------
Fa0/1 Desg LRN 19 128.1 P2p
ASW2#2: %SYS-5-CONFIG_I: Configured from console by console
ASW2#
*Mar 1 00:12:17.274: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
ASW2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
ASW2(config)#do sh spa
ASW2(config)#do sh spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 0026.ca6b.e980
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 1 (priority 0 sys-id-ext 1)
Address 0026.ca6b.e980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
ASW2(config)#do ping 172.16.0.11 repeat 10000
Type escape sequence to abort.
Sending 10000, 100-byte ICMP Echos to 172.16.0.11, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.
Success rate is 99 percent (893/894), round-trip min/avg/max = 1/5/1007 ms
ASW2(config)#
References
tech/network/cisco/stp/loopguard/loopguard.txt · Last modified: 2019/06/08 16:09 by wnoguchi
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