ループガード

loopガード。bpduが途絶えると検知する。

cata1#sho run interface fastEthernet 0/3
Building configuration...

Current configuration : 134 bytes
!
interface FastEthernet0/3
switchport access vlan 10
switchport mode access
spanning-tree portfast
spanning-tree guard loop
end

cata1#
02:48:31: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to down
02:48:32: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to down
02:48:35: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to up
02:48:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to up



cata1#sho spanning-tree

VLAN0010
Spanning tree enabled protocol ieee
Root ID Priority 10
Address 0016.9da0.4ec0
Cost 19
Port 3 (FastEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
Address 000f.90b3.b380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Back BLK 19 128.2 P2p
Fa0/3 Root FWD 19 128.3 P2p




Cata2950_2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Cata2950_2(config)#no spanning-tree vlan 10
Cata2950_2(config)#end




cata1#sho spanning-tree

VLAN0010
Spanning tree enabled protocol ieee
Root ID Priority 10
Address 0016.9da0.4ec0
Cost 19
Port 3 (FastEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
Address 000f.90b3.b380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15

Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Back BLK 19 128.2 P2p
Fa0/3 Desg BKN*19 128.3 P2p *LOOP_Inc

cata1#
02:49:47: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port FastEthernet0/3 on VLAN0010.
cata1#sho spanning-tree

VLAN0010
Spanning tree enabled protocol ieee
Root ID Priority 32778
Address 000f.90b3.b380
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
Address 000f.90b3.b380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15

Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Back BLK 19 128.2 P2p
Fa0/3 Desg BKN*19 128.3 P2p *LOOP_Inc

cata1#
cata1#sho spanning-tree interface fastEthernet 0/3 detail
Port 3 (FastEthernet0/3) of VLAN0010 is broken (Loop Inconsistent)
Port path cost 19, Port priority 128, Port Identifier 128.3.
Designated root has priority 32778, address 000f.90b3.b380
Designated bridge has priority 32778, address 000f.90b3.b380
Designated port id is 128.3, designated path cost 0
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
Loop guard is enabled on the port
BPDU: sent 2, received 28
cata1#



cata1#show spanning-tree inconsistentports


Name Interface Inconsistency
-------------------- ---------------------- ------------------
VLAN0010 FastEthernet0/3 Loop Inconsistent

Number of inconsistent ports (segments) in the system : 1

「portfastとループガードは同時に設定できない」と、黒本に書いてあり、ciscoのサイトにもそういう記述があったけど、 設定できるぜぇ？

cata1#sho spanning-tree interface fastEthernet 0/3 detail

 Port 3 (FastEthernet0/3) of VLAN0010 is forwarding
   Port path cost 19, Port priority 128, Port Identifier 128.3.
   Designated root has priority 16394, address 000b.fdb9.a680
   Designated bridge has priority 32778, address 000f.90b3.b380
   Designated port id is 128.3, designated path cost 19
   Timers: message age 0, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   The port is in the portfast mode
   Link type is point-to-point by default
   Loop guard is enabled on the port
   BPDU: sent 250, received 0
cata1#

ね？