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Contents
show dot1q-tunnel through show udld
- show dot1q-tunnel
- show errdisable flap-values
- show mac-address-table
- show mac-address-table aging-time
- show mac-address-table dynamic
- show mac-address-table learning
- show mac-address-table static
- show spanning-tree
- show udld
show dot1q-tunnel
To display a list of 802.1Q tunnel-enabled ports, use the showdot1q-tunnel command in user EXEC mode.
Usage Guidelines
If you do not enter any keywords, the 802.1Q tunnel ports for all interfaces are displayed.
The ge-wan keyword is not supported in Cisco 7600 series routers that are configured with a Supervisor Engine 720.
The interface-numberargument designates the module and port number for the ethernet, fastethernet, gigabitethernet, tengigabitethernet, and ge-wan keywords. Valid values depend on the chassis and module that are used. For example, if you have a 48-port 10/100BASE-T Ethernet module that is installed in a 13-slot chassis, valid values for the slot number are from 1 to 13 and valid values for the port number are from 1 to 48.
The interface-numberargument designates the port-channel number for the port-channel keyword; valid values are fro m 1 to 282. The values from 257 to 282 are supported on the Content Switching Module (CSM) and the Firewall Services Module (FWSM) only.
show errdisable flap-values
To display conditions that cause a flap error to be recognized as a result of a specific cause, use the showerrdisableflap-values command in user EXEC or privileged EXEC mode.
Usage Guidelines
The Flaps column in the display shows how many changes to the state within the specified time interval will cause an error to be detected and a port to be disabled. For example, the display in the “Examples” section shows that an error will be assumed and the port shut down if three Dynamic Trunking Protocol (DTP)-state (port mode access/trunk) or Port Aggregation Protocol (PAgP) flap changes occur during a 30-second interval, or if 5 link-state (link up/down) changes occur during a 10-second interval.
Examples
The following is sample output from the showerrdisableflap-values command:
Router# show errdisable flap-values ErrDisable Reason Flaps Time (sec) ----------------- ------ ---------- pagp-flap 3 30 dtp-flap 3 30 link-flap 20 10The table below describes the significant fields shown in the display.
Table 1 show errdisable flap-values Field Descriptions Field
Description
ErrDisable Reason
Reason for error disable.
Flaps
Total number of flaps.
Time (sec)
Time set for the recovery timer, in seconds.
pagp-flap
PAgP flap error disable.
dtp-flap
DTP flap error disable.
link-flap
Link flap error disable.
show mac-address-table
Cisco 2600, 3600, and 3700 Series Routers
show mac-address-table [ secure | self | count ] [ addressmacaddress ] [ interfacetype/number ] { fa | gislot/port } [ atmslot/port ] [ atmslot/port ] [ vlanvlan-id ]
Catalyst 4500 Series Switches
show mac-address-table { assigned | ip | ipx | other }
Catalyst 6000/6500 Series Switches and 7600 Series Routers
show mac-address-table [ address mac-addr [ all | interface type/number | module number | vlan vlan-id ] | aging-time [ vlan vlan-id ] | count [ module number | vlan vlan-id ] | interface type/number | limit [ vlan vlan-id | module number | interface type ] | module number | multicast [ count ] [ igmp-snooping | mld-snooping | user ] [ vlan vlan-id ] | notification { mac-move [ counter [ vlan ] ] | threshold | change } [ interface [ number ] ] | synchronize statistics | unicast-flood | vlan vlan-id [ all | module number ] ]
Syntax Description
secure
(Optional) Displays only the secure addresses.
self
(Optional) Displays only addresses added by the switch itself.
count
(Optional) Displays the number of entries that are currently in the MAC address table.
address mac-addr
(Optional) Displays information about the MAC address table for a specific MAC address. See the �Usage Guidelines� section for formatting information.
interface type / number
(Optional) Displays addresses for a specific interface. For the Catalyst 6500 and 6000 series switches, valid values are atm, fastethernet, gigabitethernet, and port-channel. For the Cisco 7600 series, valid values are atm,ethernet, fastethernet, ge-wan, gigabitethernet, tengigabitethernet, and pos.
fa
(Optional) Specifies the Fast Ethernet interface.
gi
(Optional) Specifies the Gigabit Ethernet interface.
slot / port
(Optional) Adds dynamic addresses to the module in slot 1 or 2. The slash mark is required.
atm slot /port
(Optional) Adds dynamic addresses to ATM module slot /port . Use 1 or 2 for the slot number. Use 0 as the port number. The slash mark is required.
vlan vlan -id
(Optional) Displays addresses for a specific VLAN. For the Cisco 2600, 3600, and 3700 series, valid values are from 1 to 1005; do not enter leading zeroes. Beginning with Cisco IOS Release 12.4(15)T, the valid VLAN ID range is from 1 to 4094.
For the Catalyst 6500 and 6000 series switches and 7600 series, valid values are from 1 to 4094.
assigned
Specifies the assigned protocol entries.
ip
Specifies the IP protocol entries.
ipx
Specifies the IPX protocol entries.
other
Specifies the other protocol entries.
all
(Optional) Displays every instance of the specified MAC address in the forwarding table.
type / number
(Optional) Module and interface number.
module number
(Optional) Displays information about the MAC address table for a specific Distributed Forwarding Card (DFC) module.
aging-time
(Optional) Displays the aging time for the VLANs.
limit
Displays MAC-usage information.
multicast
Displays information about the multicast MAC address table entries only.
igmp-snooping
Displays the addresses learned by Internet Group Management Protocol (IGMP) snooping.
mld-snooping
Displays the addresses learned by Multicast Listener Discover version 2 (MLDv2) snooping.
user
Displays the manually entered (static) addresses.
notification mac-move
Displays the MAC-move notification status.
notification mac-move counter
(Optional) Displays the number of times a MAC has moved and the number of these instances that have occurred in the system.
vlan
(Optional) Specifies a VLAN to display. For the Catalyst 6500 and 6000 series switches and 7600 series, valid values are from 1 to 4094.
notification threshold
Displays the Counter-Addressable Memory (CAM) table utilization notification status.
notification change
Displays the MAC notification parameters and history table.
synchronize statistics
Displays information about the statistics collected on the switch processor or DFC.
unicast-flood
Displays unicast-flood information.
Command History
Usage Guidelines
Cisco 2600, 3600, and 3700 Series Routers
The show mac-address-table command displays the MAC address table for the switch. Specific views can be defined by using the optional keywords and arguments. If more than one optional keyword is used, then all the conditions must be true for that entry to be displayed.
Catalyst 4500 Series Switches
For the MAC address table entries that are used by the routed ports, the routed port name, rather than the internal VLAN number, is displayed in the �vlan� column.
Catalyst 6000 and 6500 Series Switches and Cisco 7600 Series Routers
If you do not specify a module number, the output of the show mac-address-table command displays information about the supervisor engine. To display information about the MAC address table of the DFCs, you must enter the module number or the all keyword.
The mac-addrvalue is a 48-bit MAC address. The valid format is H.H.H.
The interface number argument designates the module and port number. Valid values depend on the specified interface type and the chassis and module that are used. For example, if you specify a Gigabit Ethernet interface and have a 48-port 10/100BASE-T Ethernet module that is installed in a 13-slot chassis, valid values for the module number are from 1 to 13 and valid values for the port number are from 1 to 48.
The optional module number keyword-argument pair is supported only on DFC modules. The module numberkeyword-argument pair designate the module number.
Valid values for the mac-group-address argument are from 1 to 9.
The optional count keyword displays the number of multicast entries.
The optional multicast keyword displays the multicast MAC addresses (groups) in a VLAN or displays all statically installed or IGMP snooping-learned entries in the Layer 2 table.
The information that is displayed in the show mac-address-table unicast-flood command output is as follows:
- Up to 50 flood entries, shared across all the VLANs that are not configured to use the filter mode, can be recorded.
NoteThe information displayed on the destination MAC addresses is deleted as soon as the floods stop after the port shuts down.
- Information is updated each time that you install the filter. The information lasts until you remove the filter.
The dynamic entries that are displayed in the Learn field are always set to Yes.
The show mac-address-table limit command output displays the following information:
- The current number of MAC addresses.
- The maximum number of MAC entries that are allowed.
- The percentage of usage.
The show mac-address-table synchronize statistics command output displays the following information:
Examples
The following is sample output from theshow mac-address-table command:
Switch# show mac-address-table Dynamic Addresses Count: 9 Secure Addresses (User-defined) Count: 0 Static Addresses (User-defined) Count: 0 System Self Addresses Count: 41 Total MAC addresses: 50 Non-static Address Table: Destination Address Address Type VLAN Destination Port ------------------- ------------ ---- -------------------- 0010.0de0.e289 Dynamic 1 FastEthernet0/1 0010.7b00.1540 Dynamic 2 FastEthernet0/5 0010.7b00.1545 Dynamic 2 FastEthernet0/5 0060.5cf4.0076 Dynamic 1 FastEthernet0/1 0060.5cf4.0077 Dynamic 1 FastEthernet0/1 0060.5cf4.1315 Dynamic 1 FastEthernet0/1 0060.70cb.f301 Dynamic 1 FastEthernet0/1 00e0.1e42.9978 Dynamic 1 FastEthernet0/1 00e0.1e9f.3900 Dynamic 1 FastEthernet0/1Examples
The following example shows how to display the MAC address table entries that have a specific protocol type (in this case, "assigned"):
Switch# show mac-address-table protocol assigned vlan mac address type protocol qos ports -----+---------------+--------+---------+---+-------------------------------- 200 0050.3e8d.6400 static assigned -- Switch 100 0050.3e8d.6400 static assigned -- Switch 5 0050.3e8d.6400 static assigned -- Switch 4092 0000.0000.0000 dynamic assigned -- Switch 1 0050.3e8d.6400 static assigned -- Switch 4 0050.3e8d.6400 static assigned -- Switch 4092 0050.f0ac.3058 static assigned -- Switch 4092 0050.f0ac.3059 dynamic assigned -- Switch 1 0010.7b3b.0978 dynamic assigned -- Fa5/9The following example shows the "other" output for the previous example:
Switch# show mac-address-table protocol other Unicast Entries vlan mac address type protocols port -------+---------------+--------+---------------------+-------------------- 1 0000.0000.0201 dynamic other FastEthernet6/15 1 0000.0000.0202 dynamic other FastEthernet6/15 1 0000.0000.0203 dynamic other FastEthernet6/15 1 0000.0000.0204 dynamic other FastEthernet6/15 1 0030.94fc.0dff static ip,ipx,assigned,other Switch 2 0000.0000.0101 dynamic other FastEthernet6/16 2 0000.0000.0102 dynamic other FastEthernet6/16 2 0000.0000.0103 dynamic other FastEthernet6/16 2 0000.0000.0104 dynamic other FastEthernet6/16 Fa6/1 0030.94fc.0dff static ip,ipx,assigned,other Switch Fa6/2 0030.94fc.0dff static ip,ipx,assigned,other Switch Multicast Entries vlan mac address type ports -------+---------------+-------+------------------------------------------- 1 ffff.ffff.ffff system Switch,Fa6/15 2 ffff.ffff.ffff system Fa6/16 1002 ffff.ffff.ffff system 1003 ffff.ffff.ffff system 1004 ffff.ffff.ffff system 1005 ffff.ffff.ffff system Fa6/1 ffff.ffff.ffff system Switch,Fa6/1 Fa6/2 ffff.ffff.ffff system Switch,Fa6/2Examples
The following is sample output from theshow mac-address-tablecommand:
Switch# show mac-address-table Dynamic Addresses Count: 9 Secure Addresses (User-defined) Count: 0 Static Addresses (User-defined) Count: 0 System Self Addresses Count: 41 Total MAC addresses: 50 Non-static Address Table: Destination Address Address Type VLAN Destination Port ------------------- ------------ ---- -------------------- 0010.0de0.e289 Dynamic 1 FastEthernet0/1 0010.7b00.1540 Dynamic 2 FastEthernet0/5 0010.7b00.1545 Dynamic 2 FastEthernet0/5 0060.5cf4.0076 Dynamic 1 FastEthernet0/1 0060.5cf4.0077 Dynamic 1 FastEthernet0/1 0060.5cf4.1315 Dynamic 1 FastEthernet0/1 0060.70cb.f301 Dynamic 1 FastEthernet0/1 00e0.1e42.9978 Dynamic 1 FastEthernet0/1 00e0.1e9f.3900 Dynamic 1 FastEthernet0/1
NoteIn a distributed Encoded Address Recognition Logic (EARL) switch, the asterisk (*) indicates a MAC address that is learned on a port that is associated with this EARL.
The following example shows how to display the information about the MAC address table for a specific MAC address with a Supervisor Engine 720:
Switch# show mac-address-table address 001.6441.60ca Codes: * - primary entry vlan mac address type learn qos ports ------+----------------+--------+-----+---+-------------------------- Supervisor: * --- 0001.6441.60ca static No -- RouterThe following example shows how to display MAC address table information for a specific MAC address with a Supervisor Engine 720:
Router# show mac-address-table address 0100.5e00.0128 Legend: * - primary entry age - seconds since last seen n/a - not available vlan mac address type learn age ports ------+----------------+--------+-----+----------+-------------------------- Supervisor: * 44 0100.5e00.0128 static Yes - Fa6/44,Router * 1 0100.5e00.0128 static Yes - Router Module 9: * 44 0100.5e00.0128 static Yes - Fa6/44,Router * 1 0100.5e00.0128 static Yes - RouterThe following example shows how to display the currently configured aging time for all VLANs:
Switch# show mac-address-table aging-time Vlan Aging Time ---- ---------- *100 300 200 1000The following example shows how to display the entry count for a specific slot:
Switch# show mac-address-table count module 1 MAC Entries on slot 1 : Dynamic Address Count: 4 Static Address (User-defined) Count: 25 Total MAC Addresses In Use: 29 Total MAC Addresses Available: 131072The following example shows how to display the information about the MAC address table for a specific interface with a Supervisor Engine 720:
Switch# show mac-address-table interface fastethernet 6/45 Legend: * - primary entry age - seconds since last seen n/a - not available vlan mac address type learn age ports ------+----------------+--------+-----+----------+-------------------------- * 45 00e0.f74c.842d dynamic Yes 5 Fa6/45
NoteA leading asterisk (*) indicates entries from a MAC address that was learned from a packet coming from an outside device to a specific module.
The following example shows how to display the limit information for a specific slot:
Switch# show mac-address-table limit vlan 1 module 1 vlan switch module action maximum Total entries flooding -------+--------+---------+-----------+--------+--------------+------------ 1 1 7 warning 500 0 enabled 1 1 11 warning 500 0 enabled 1 1 12 warning 500 0 enabled Router#show mac-address-table limit vlan 1 module 2 vlan switch module action maximum Total entries flooding -------+--------+---------+-----------+--------+--------------+------------ 1 2 7 warning 500 0 enabled 1 2 9 warning 500 0 enabledThe following example shows how to display the MAC-move notification status:
Switch# show mac-address-table notification mac-move MAC Move Notification: EnabledThe following example shows how to display the MAC move statistics:
Router# show mac-address-table notification mac-move counter ----------------------------------------------------------------------------------- Vlan Mac Address From Mod/Port To Mod/Port Count ---- ----------------- ----------------------- ----------------------- ------------ 1 00-01-02-03-04-01 2/3 3/1 10 20 00-01-05-03-02-01 5/3 5/1 20The following example shows how to display the CAM-table utilization-notification status:
Router# show mac-address-table notification threshold Status limit Interval -------------+-----------+------------- enabled 1 120The following example shows how to display the MAC notification parameters and history table:
Switch# show mac-address-table notification change MAC Notification Feature is Disabled on the switch MAC Notification Flags For All Ethernet Interfaces : ---------------------------------------------------- Interface MAC Added Trap MAC Removed Trap -------------------- -------------- ----------------The following example shows how to display the MAC notification parameters and history table for a specific interface:
Switch# show mac-address-table notification change interface gigabitethernet5/2 MAC Notification Feature is Disabled on the switch Interface MAC Added Trap MAC Removed Trap -------------------- -------------- ---------------- GigabitEthernet5/2 Disabled DisabledThe following example shows how to display unicast-flood information:
Switch# show mac-address-table unicast-flood > > Unicast Flood Protection status: enabled > > > > Configuration: > > vlan Kfps action timeout > > ------+----------+-----------------+---------- > > 2 2 alert none > > > > Mac filters: > > No. vlan source mac addr. installed > > on time left (mm:ss) > > > >-----+------+-----------------+------------------------------+------------------ > > > > Flood details: > > Vlan source mac addr. destination mac addr. > > > >------+----------------+------------------------------------------------- > > 2 0000.0000.cafe 0000.0000.bad0, 0000.0000.babe, > > 0000.0000.bac0 > > 0000.0000.bac2, 0000.0000.bac4, > > 0000.0000.bac6 > > 0000.0000.bac8 > > 2 0000.0000.caff 0000.0000.bad1, 0000.0000.babf, > > 0000.0000.bac1 > > 0000.0000.bac3, 0000.0000.bac5, > > 0000.0000.bac7 > > 0000.0000.bac9The following example shows how to display the information about the MAC-address table for a specific VLAN:
Switch#show mac-address-table vlan 100 vlan mac address type protocol qos ports -----+---------------+--------+---------+---+-------------------------------- 100 0050.3e8d.6400 static assigned -- Router 100 0050.7312.0cff dynamic ip -- Fa5/9 100 0080.1c93.8040 dynamic ip -- Fa5/9 100 0050.3e8d.6400 static ipx -- Router 100 0050.3e8d.6400 static other -- Router 100 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 100 00d0.5870.a4ff dynamic ip -- Fa5/9 100 00e0.4fac.b400 dynamic ip -- Fa5/9 100 0100.5e00.0001 static ip -- Fa5/9,Switch 100 0050.3e8d.6400 static ip -- RouterThe following example shows how to display the information about the MAC address table for MLDv2 snooping:
Switch# show mac-address-table multicast mld-snooping vlan mac address type learn qos ports -----+---------------+--------+-----+---+-------------------------------- --- 3333.0000.0001 static Yes - Switch,Stby-Switch --- 3333.0000.000d static Yes - Fa2/1,Fa4/1,Router,Switch --- 3333.0000.0016 static Yes - Switch,Stby-SwitchThe table below describes the significant fields shown in the displays.
Table 2 show mac-address-table Field Descriptions Field
Description
Dynamic Addresses Count
Total number of dynamic addresses in the MAC address table.
Secure Addresses (User-defined) Count
Total number of secure addresses in the MAC address table.
Static Addresses (User-defined) Count
Total number of static addresses in the MAC address table.
System Self Addresses Count
Total number of addresses in the MAC address table.
Total MAC addresses
Total MAC addresses in the MAC address table.
Destination Address
Destination addresses present in the MAC address table.
Address Type
Address type: static or dynamic.
VLAN
VLAN number.
Destination Port
Destination port information present in the MAC address table.
mac address
The MAC address of the entry.
protocol
Protocol present in the MAC address table.
qos
Quality of service associated with the MAC address table.
ports
Port type.
age
The time in seconds since last occurrence of the interface.
Aging Time
Aging time for entries.
module
Module number.
action
Type of action.
flooding
Status of the flooding.
Related Commands
Command
Description
clear mac-address-table
Deletes entries from the MAC address table.
mac-address-table aging-time
Configures the aging time for entries in the Layer 2 table.
mac-address-table limit
Enables MAC limiting.
mac-address-table notification mac-move
Enables MAC-move notification.
mac-address-table static
Adds static entries to the MAC address table or configures a static MAC address with IGMP snooping disabled for that address.
mac-address-table synchronize
Synchronizes the Layer 2 MAC address table entries across the PFC and all the DFCs.
show mac-address-table static
Displays only static MAC address table entries.
show mac-address-table aging-time
To display the MAC address aging time, use the showmac-address-tableaging-time command in privileged EXEC mode.
Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
show mac-address-table aging-time
Catalyst Switches
show mac-address-table aging-time [ vlan vlan-id ] [ [ begin | exclude | include ] expression ]
Syntax Description
vlan vlan-id
(Optional) Specifies a VLAN; valid values are from 1 to 1005.
begin
(Optional) Specifies that the output display begin with the line that matches the expression .
exclude
(Optional) Specifies that the output display exclude lines that match the expression .
include
(Optional) Specifies that the output display include lines that match the specified expression .
expression
Expression in the output to use as a reference point.
Command History
Release
Modification
12.0(7)XE
This command was introduced on Catalyst 6000 series switches.
12.2(2)XT
This command was implemented on Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(8)T
This command was integrated into Cisco IOS Release 12.2(8)T on Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(11)T
This command was integrated into Cisco IOS Release 12.2(11)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Examples
The following example shows how to display the current configured aging time for all VLANs. The fields shown in the display are self-explanatory.
Examples
Router# show mac-address-table aging-time Vlan Aging Time ---- ---------- 100 300 200 1000The following example shows how to display the current configured aging time for a specific VLAN. The fields shown in the display are self-explanatory.
Router# show mac-address-table aging-time vlan 100 Vlan Aging Time ---- ---------- 100 300Related Commands
Command
Description
show mac -address-tableaddress
Displays MAC address table information for a specific MAC address.
show mac -address-tablecount
Displays the number of entries currently in the MAC address table.
show mac -address-tabledetail
Displays detailed MAC address table information.
show mac -address-tabledynamic
Displays dynamic MAC address table entries only.
show mac -address-tableinterface
Displays the MAC address table information for a specific interface.
show mac -address-tablemulticast
Displays multicast MAC address table information.
show mac -address-tableprotocol
Displays MAC address table information based on protocol.
show mac -address-tablestatic
Displays static MAC address table entries only.
show mac -address-tablevlan
Displays the MAC address table information for a specific VLAN.
show mac-address-table dynamic
To display dynamic MAC address table entries only, use the showmac-address-tabledynamic command in privileged EXEC mode.
Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
show mac-address-table dynamic [ address mac-addr | interface interface type slot/number | vlan vlan ]
Catalyst Switches
show mac-address-table dynamic [ address mac-addr | detail | interface interface numberprotocol protocol | module number | vlan vlan ] [ begin | exclude | include | expression ]
Catalyst 6500 Series Switches
show mac-address-table dynamic [ address mac-addr | interface interface interface-number [ all | module number ] | module num | vlan vlan-id [ all | module number ] ]
Syntax Description
Command History
Release
Modification
12.0(7)XE
This command was introduced on Catalyst 6000 series switches.
12.2(2)XT
This command was implemented on Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(8)T
This command was integrated into Cisco IOS Release 12.2(8)T on Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(11)T
This command was integrated into Cisco IOS Release 12.2(11)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(14)SX
Support for this command was introduced on the Catalyst 6500 series switch.
12.2(33)SXH
This command was changed to support the all keyword on the Catalyst 6500 series switch.
Usage Guidelines
Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
The showmac-address-tabledynamic command output for an EtherChannel interface changes the port-number designation (for example, 5/7) to a port-group number.
Catalyst Switches
The keyword definitions for the protocol argument are:
- ip --Specifies IP protocol
- ipx --Specifies Internetwork Packet Exchange (IPX) protocols
- assigned --Specifies assigned protocol entries
- other --Specifies other protocol entries
The showmac-address-tabledynamic command output for an EtherChannel interface changes the port-number designation (for example, 5/7) to a port-group number.
Catalyst 6500 Series Switches
The mac-addressis a 48-bit MAC address and the valid format is H.H.H.
The optional modulenum keyword and argument are supported only on DFC modules. The modulenumkeyword and argument designate the module number.
Examples
The following examples show how to display all dynamic MAC address entries. The fields shown in the various displays are self-explanatory.
Examples
Router# show mac-address-table dynamic Non-static Address Table: Destination Address Address Type VLAN Destination Port ------------------- ------------ ---- -------------------- 000a.000a.000a Dynamic 1 FastEthernet4/0 002a.2021.4567 Dynamic 2 FastEthernet4/0Examples
Router# show mac-address-table dynamic vlan mac address type protocol qos ports -----+---------------+--------+---------+---+-------------------------------- 200 0010.0d40.37ff dynamic ip -- 5/8 1 0060.704c.73ff dynamic ip -- 5/9 4095 0000.0000.0000 dynamic ip -- 15/1 1 0060.704c.73fb dynamic other -- 5/9 1 0080.1c93.8040 dynamic ip -- 5/9 4092 0050.f0ac.3058 dynamic ip -- 15/1 1 00e0.4fac.b3ff dynamic other -- 5/9The following example shows how to display dynamic MAC address entries with a specific protocol type (in this case, assigned).
Router# show mac-address-table dynamic protocol assigned vlan mac address type protocol qos ports -----+---------------+--------+---------+---+-------------------------------- 4092 0000.0000.0000 dynamic assigned -- Router 4092 0050.f0ac.3059 dynamic assigned -- Router 1 0010.7b3b.0978 dynamic assigned -- Fa5/9 Router#The following example shows the detailed output for the previous example.
Router# show mac-address-table dynamic protocol assigned detail MAC Table shown in details ======================================== Type Always Learn Trap Modified Notify Capture Protocol Flood -------+------------+----+--------+------+-------+--------+-----+ QoS bit L3 Spare Mac Address Age Byte Pvlan Xtag SWbits Index -----------------+--------+--------------+--------+-----+----+------+----- DYNAMIC NO NO YES NO NO assigned NO Bit Not On 0 0000.0000.0000 255 4092 0 0 0x3 DYNAMIC NO NO YES NO NO assigned NO Bit Not On 0 0050.f0ac.3059 254 4092 0 0 0x3 DYNAMIC NO NO YES NO NO assigned NO Bit Not On 0 0010.7b3b.0978 254 1 0 0 0x108 Router#Examples
This example shows how to display all the dynamic MAC-address entries for a specific VLAN.
Router# show mac-address-table dynamic vlan 200 all Legend: * - primary entry age - seconds since last seen n/a - not aevailable vlan mac address type learn age ports ------+----------------+--------+-----+----------+-------------------------- 200 0010.0d40.37ff dynamic NO 23 Gi5/8 Router#This example shows how to display all the dynamic MAC-address entries.
Router# show mac-address-table dynamic Legend: * - primary entry age - seconds since last seen n/a - not applicable vlan mac address type learn age ports ------+----------------+--------+-----+----------+-------------------------- * 10 0010.0000.0000 dynamic Yes n/a Gi4/1 * 3 0010.0000.0000 dynamic Yes 0 Gi4/2 * 1 0002.fcbc.ac64 dynamic Yes 265 Gi8/1 * 1 0009.12e9.adc0 static No - Router Router#Related Commands
Command
Description
show mac -address-tableaddress
Displays MAC address table information for a specific MAC address.
show mac -address-tableaging-time
Displays the MAC address aging time.
show mac -address-tablecount
Displays the number of entries currently in the MAC address table.
show mac -address-tabledetail
Displays detailed MAC address table information.
show mac -address-tableinterface
Displays the MAC address table information for a specific interface.
show mac -address-tablemulticast
Displays multicast MAC address table information.
show mac -address-tableprotocol
Displays MAC address table information based on protocol.
show mac -address-tablestatic
Displays static MAC address table entries only.
show mac -address-tablevlan
Displays the MAC address table information for a specific VLAN.
show mac-address-table learning
To display the MAC-address learning state, use the showmac-address-tablelearning command in user EXEC mode.
Syntax Description
vlan vlan-id
(Optional) Displays information about the MAC-address learning state for the specified switch port VLAN; valid values are from 1 to 4094.
interface interface slot / port
(Optional) Displays information about the MAC-address learning state for the specified routed interface type, the slot number, and the port number.
module num
(Optional) Displays information about the MAC-address learning state for the specified module number.
Usage Guidelines
The modulenum keyword and argument can be used to specify supervisor engines or Distributed Forwarding Cards (DFCs) only.
The interfaceinterfaceslot/port keyword and arguments can be used on routed interfaces only. The interfaceinterfaceslot/port keyword and arguments cannot be used to configure learning on switch-port interfaces.
If you specify the vlanvlan-id, the state of the MAC-address learning of the specified VLAN, including router interfaces, on all modules, is displayed.
If you specify the vlanvlan-id and the modulenum, the state of the MAC-address learning of a specified VLAN on a specified module is displayed.
If you specify the interfaceinterfaceslot/port keyword and arguments, the state of the MAC-address learning of the specified interface on all modules is displayed.
If you specify the interfaceinterfaceslot/port keyword and arguments, the state of the MAC-address learning of the specified interface on the specified module is displayed.
If you enter the showmac-address-tablelearningcommand with no arguments or keywords, the status of MAC learning on all the existing VLANs on all the supervisor engines or DFCs configured on a Cisco 7600 series router is displayed.
Examples
This example shows how to display the MAC-address learning status on all the existing VLANs on all the supervisor engines or DFCs configured on a Cisco 7600 series router:
Router# show mac-address-table learning VLAN/Interface Mod1 Mod4 Mod7 -------------------- --------------------- 1 yes yes yes 100 yes yes yes 150 yes yes yes 200 yes yes yes 250 yes yes yes 1006 no no no 1007 no no no 1008 no no no 1009 no no no 1010 no no no 1011 no no no 1012 no no no 1013 no no no 1014 no no no GigabitEthernet6/1 no no no GigabitEthernet6/2 no no no GigabitEthernet6/4 no no no FastEthernet3/4 no no no FastEthernet3/5 no no no GigabitEthernet4/1 no no no GigabitEthernet4/2 no no no GigabitEthernet7/1 no no no GigabitEthernet7/2 no no no Router#Table 1 describes the fields that are shown in the example.
Table 3 show mac-address-table learning Field Descriptions Field
Description
VLAN/Interface1
VLAN ID or interface type, module, and port number.
Mod#
Module number of a supervisor engine or DFC.
yes
MAC-address learning is enabled.
no
MAC-address learning is disabled.
1 The interfaces displayed are routed interfaces that have internal VLANs assigned to them.This example shows how to display the status of MAC-address learning on all the existing VLANs on a single supervisor engine or a DFC:
Router# show mac-address-table learning module 4 VLAN/Interface Mod4 -------------------- ----- 1 yes 100 yes 150 yes 200 yes 250 yes 1006 no 1007 no 1008 no 1009 no 1010 no 1011 no 1012 no 1013 no 1014 no GigabitEthernet6/1 no GigabitEthernet6/2 no GigabitEthernet6/4 no FastEthernet3/4 no FastEthernet3/5 no GigabitEthernet4/1 no GigabitEthernet4/2 no GigabitEthernet7/1 no GigabitEthernet7/2 no Router#This example shows how to display the status of MAC-address learning for a specific VLAN on all the supervisor engines and DFCs:
Router# show mac-address-table learning vlan 100 VLAN Mod1 Mod4 Mod7 ---- --------------------- 100 no no yes RouterThis example shows how to display the status of MAC-address learning for a specific VLAN on a specific supervisor engine or DFC:
Router# show mac-address-table learning vlan 100 module 7 VLAN Mod7 ---- ----- 100 yes RouterThis example shows how to display the status of MAC-address learning for a specific supervisor engine or DFC:
Router# show mac-address-table learning interface FastEthernet 3/4 Interface Mod1 Mod4 Mod7 --------- --------------------- Fa3/4 no yes no RouterThis example shows how to display the status of MAC-address learning for a specific interface on a specific supervisor engine or DFC:
Router# show mac-address-table learning interface FastEthernet 3/4 module 1 Interface Mod1 --------- ----- Fa3/4 no Routershow mac-address-table static
To display static MAC address table entries only, use the showmac-address-tablestatic command in privileged EXEC mode.
Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
show mac-address-table static [ address mac-address | interface type /slot number | vlan vlan-id ]
Catalyst Switches
show mac-address-table static [ address mac-address | detail | interface type number | protocol protocol | vlan vlan-id ] [ [ begin | exclude | include ] expression ]
Syntax Description
Command History
Release
Modification
12.0(7)XE
This command was introduced on Catalyst 6000 series switches.
12.2(2)XT
This command was implemented on Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(8)T
This command was integrated into Cisco IOS Release 12.2(8)T on Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(11)T
This command was integrated into Cisco IOS Release 12.2(11)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Examples
The following examples show how to display all static MAC address entries. The fields shown in the various displays are self-explanatory.
Examples
Router# show mac-address-table static Static Address Table: Destination Address Address Type VLAN Destination Port ------------------- ------------ ---- -------------------- 2323.3214.5432 Static 4 FastEthernet4/1 2323.3214.5431 Static 5 FastEthernet4/1 2323.3214.5432 Static 6 FastEthernet4/1 2323.3214.5434 Static 7 FastEthernet4/1 2323.3214.5435 Static 8 FastEthernet4/1Examples
Router# show mac-address-table static *Oct 22 12:15:35: %SYS-5-CONFIG_I: Configured from console by console vlan mac address type protocol qos ports -----+---------------+--------+---------+---+-------------------------------- 200 0050.3e8d.6400 static assigned -- Router 100 0050.3e8d.6400 static assigned -- Router 4092 0050.f0ac.3058 static other -- Router 917 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 5 0050.3e8d.6400 static assigned -- Router 303 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 850 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 1002 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 802 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 2 0100.0cdd.dddd static other -- Fa5/9,Router,Switch 304 0100.5e00.0001 static ip -- Fa5/9,Switch . . .The following example shows how to display static MAC address entries with a specific protocol type (in this case, assigned).
Router# show mac-address-table static protocol assigned vlan mac address type protocol qos ports -----+---------------+--------+---------+---+-------------------------------- 200 0050.3e8d.6400 static assigned -- Router 100 0050.3e8d.6400 static assigned -- Router 5 0050.3e8d.6400 static assigned -- RouterThe following example shows the detailed output for the previous example.
Router# show mac-address-table static protocol assigned detail MAC Table shown in details ======================================== Type Always Learn Trap Modified Notify Capture Protocol Flood -------+------------+----+--------+------+-------+--------+-----+ QoS bit L3 Spare Mac Address Age Byte Pvlan Xtag SWbits Index -----------------+--------+--------------+--------+-----+----+------+----- STATIC NO NO NO NO NO assigned NO Bit Not On 0 0050.3e8d.6400 254 200 1 0 0x3 STATIC NO NO NO NO NO assigned NO Bit Not On 0 0050.3e8d.6400 254 100 1 0 0x3 STATIC NO NO NO NO NO assigned NO Bit Not On 0 0050.3e8d.6400 254 5 1 0 0x3 S Bit Not On 0 0050.f0ac.3058 254 4092 1 0 0x3 . . .Examples
This example shows how to display all the static MAC address entries; this Cisco 7600 series router is configured with a Supervisor Engine 720.
Router# show mac-address-table static Codes: * - primary entry vlan mac address type learn qos ports ------+----------------+--------+-----+---+-------------------------- * --- 0001.6441.60ca static No -- RouterRelated Commands
Command
Description
show mac -address-tableaddress
Displays MAC address table information for a specific MAC address.
show mac -address-tableaging-time
Displays the MAC address aging time.
show mac -address-tablecount
Displays the number of entries currently in the MAC address table.
show mac -address-tabledetail
Displays detailed MAC address table information.
show mac -address-tabledynamic
Displays dynamic MAC address table entries only.
show mac -address-tableinterface
Displays the MAC address table information for a specific interface.
show mac -address-tablemulticast
Displays multicast MAC address table information.
show mac -address-tableprotocol
Displays MAC address table information based on protocol.
show mac -address-tablevlan
Displays the MAC address table information for a specific VLAN.
show spanning-tree
Cisco 2600, 3660, and 3845 Series Switches
To display spanning-tree information for the specified spanning-tree instances, use the showspanning-tree command in privileged EXEC mode.
Cisco 6500/6000 Catalyst Series Switches and Cisco 7600 Series Routers
show spanning-tree [bridge-group] [ active | backbonefast | blockedports | bridge | brief | inconsistentports | interface interface-type interface-number | root | summary [totals] | uplinkfast | vlan vlan-id ]
show spanning-tree [ bridge-group | active | backbonefast | bridge [id] | detail | inconsistentports | interface interface-type interface-number [ portfast [edge] ] | mst [ list | configuration [digest] ] | root | summary [totals] | uplinkfast | vlan vlan-id | port-channel number | pathcost method ]
Syntax Description
bridge-group
(Optional) Specifies the bridge group number. The range is 1 to 255.
active
(Optional) Displays spanning-tree information on active interfaces only.
backbonefast
(Optional) Displays spanning-tree BackboneFast status.
blockedports
(Optional) Displays blocked port information.
bridge
(Optional) D isplays status and configuration of this switch.
brief
(Optional) Specifies a brief summary of interface information.
configuration digest ]
(Optional) D isplays the multiple spanning-tree current region configuration.
inconsistentports
(Optional) Displays information about inconsistent ports.
interface interface-type interface-number
(Optional) Specifies the type and number of the interface. Enter each interface designator, using a space to separate it from the one before and the one after. Ranges are not supported. Valid interfaces include physical ports and virtual LANs (VLANs). See the “Usage Guidelines” for valid values.
list
(Optional) Specifies a multiple spanning-tree instance list.
mst
(Optional) Specifies multiple spanning-tree.
portfast edge ]
(Optional) Displays spanning-tree PortFast edge interface operational status. Beginning with Cisco IOS Release 12.2(33)SXI, the edge keyword is required. In earlier releases, the edge keyword is not used.
root
(Optional) Displays root-switch status and configuration.
summary
(Optional) Specifies a summary of port states.
totals
(Optional) Displays the total lines of the spanning-tree state section.
uplinkfast
(Optional) Displays spanning-tree UplinkFast status.
vlan vlan-id
(Optional) Specifies the VLAN ID. The range is 1 to 1005. Beginning with Cisco IOS Release 12.4(15)T, the valid VLAN ID range is from 1 to 4094.
If the vlan-id value is omitted, the command applies to the spanning-tree instance for all VLANs.
id
(Optional) Identifies the spanning tree bridge.
detail
(Optional) Shows status and configuration details.
port-channel number
(Optional) Identifies the Ethernet channel associated with the interfaces.
pathcost method
(Optional) Displays the default path-cost calculation method that is used. See the “Usage Guidelines” section for the valid values.
Command History
Release
Modification
12.0(1)T
This command was introduced.
12.0(5.2)WC(1)
This command was integrated into Cisco IOS Release 12.0(5.2)WC(1).
12.1(6)EA2
This command was integrated into Cisco IOS Release 12.1(6)EA2. The following keywords and arguments were added: bridge-group , active, backbonefast, blockedports, bridge, inconsistentports, pathcostmethod , root, totals, and uplinkfast.
12.2(14)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(15)ZJ
The syntax added in Cisco IOS Release 12.1(6)EA2 was implemented on the Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Cisco IOS Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.3(4)T
The platform support and syntax added in Cisco IOS Release 12.2(15)ZJ was integrated into Cisco IOS Release 12.3(4)T.
12.4(15)T
This command was modified to extend the range of valid VLAN IDs to 1-4094 for specified platforms.
12.2(33)SXI
This command was modified to require the edge keyword after portfast. The command output was modified to show the status of Bridge Assurance and PVST Simulation.
Usage Guidelines
The keywords and arguments that are available with the showspanning-tree command vary depending on the platform you are using and the network modules that are installed and operational.
Cisco 2600, 3660, and 3845 Series Switches
The valid values for interfaceinterface-type are:
- fastethernet --Specifies a Fast Ethernet IEEE 802.3 interface.
- port-channel --Specifies an Ethernet channel of interfaces.
Cisco 6500/6000 Catalyst Switches and 7600 Series Routers
The port-channelnumbervalues from 257 to 282 are supported on the Content Switching Module (CSM) and the Firewal Services Module (FWSM) only.
The interface-number argument designates the module and port number. Valid values for interface-number depend on the specified interface type and the chassis and module that are used. For example, if you specify a Gigabit Ethernet interface and have a 48-port 10/100BASE-T Ethernet module that is installed in a 13-slot chassis, valid values for the module number are from 2 to 13 and valid values for the port number are from 1 to 48.
When checking spanning tree-active states and you have a large number of VLANs, you can enter the showspanning-treesummarytotal command. You can display the total number of VLANs without having to scroll through the list of VLANs.
The valid values for interfaceinterface-type are:
- fastethernet --Specifies a Fast Ethernet IEEE 802.3 interface.
- port-channel --Specifies an Ethernet channel of interfaces.
- atm --Specifies an Asynchronous Transfer Mode (ATM) interface.
- gigabitethernet --Specifies a Gigabit Ethernet IEEE 802.3z interface.
- multilink --Specifies a multilink-group interface.
- serial --Specifies a serial interface.
- vlan --Specifies a catalyst VLAN interface.
The valid values for keyword pathcoastmethod are:
- append --Appends the redirected output to a URL (supporting the append operation).
- begin --Begins with the matching line.
- exclude --Excludes matching lines.
- include --Includes matching lines.
- redirect --Redirects output to a URL.
- tee --Copies output to a URL.
When you run the showspanning-tree command for a VLAN or an interface the switch router will display the different port states for the VLAN or interface. The valid spanning-tree port states are listening, learning, forwarding, blocking, disabled, and loopback. See the table below for definitions of the port states:
Table 4 show spanning-tree vlan Command Port States Field
Definition
BLK
Blocked is when the port is still sending and listening to BPDU packets but is not forwarding traffic.
DIS
Disabled is when the port is not sending or listening to BPDU packets and is not forwarding traffic.
FWD
Forwarding is when the port is sending and listening to BPDU packets and forwarding traffic.
LBK
Loopback is when the port recieves its own BPDU packet back.
LIS
Listening is when the port spanning tree initially starts to listen for BPDU packets for the root bridge.
LRN
Learning is when the port sets the proposal bit on the BPDU packets it sends out
Examples
The following example shows that bridge group 1 is running the VLAN Bridge Spanning Tree Protocol:
Router# show spanning-tree 1 Bridge group 1 is executing the VLAN Bridge compatible Spanning Tree Protocol Bridge Identifier has priority 32768, address 0000.0c37.b055 Configured hello time 2, max age 30, forward delay 20 We are the root of the spanning tree Port Number size is 10 bits Topology change flag not set, detected flag not set Times: hold 1, topology change 35, notification 2 hello 2, max age 30, forward delay 20 Timers: hello 0, topology change 0, notification 0 bridge aging time 300 Port 8 (Ethernet1) of Bridge group 1 is forwarding Port path cost 100, Port priority 128 Designated root has priority 32768, address 0000.0c37.b055 Designated bridge has priority 32768, address 0000.0c37.b055 Designated port is 8, path cost 0 Timers: message age 0, forward delay 0, hold 0 BPDU: sent 184, received 0The following is sample output from the showspanning-treesummarycommand:
Router# show spanning-tree summary UplinkFast is disabled Name Blocking Listening Learning Forwarding STP Active -------------------- -------- --------- -------- ---------- ---------- VLAN1 23 0 0 1 24 -------------------- -------- --------- -------- ---------- ---------- 1 VLAN 23 0 0 1 24The table below describes the significant fields shown in the display.
Table 5 show spanning-tree summary Field Descriptions Field
Description
UplinkFast
Indicates whether the spanning-tree UplinkFast feature is enabled or disabled.
Name
Name of VLAN.
Blocking
Number of ports in the VLAN in a blocking state.
Listening
Number of ports in a listening state.
Learning
Number of ports in a learning state.
Forwarding
Number of ports in a forwarding state.
STP Active
Number of ports using the Spanning-Tree Protocol.
The following is sample output from the showspanning-treebriefcommand:
Router# show spanning-tree brief VLAN1 Spanning tree enabled protocol IEEE ROOT ID Priority 32768 Address 0030.7172.66c4 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec VLAN1 Spanning tree enabled protocol IEEE ROOT ID Priority 32768 Address 0030.7172.66c4 Port Designated Name Port ID Prio Cost Sts Cost Bridge ID Port ID ------- ------- ---- ---- --- ---- -------------- ------- Fa0/11 128.17 128 100 BLK 38 0404.0400.0001 128.17 Fa0/12 128.18 128 100 BLK 38 0404.0400.0001 128.18 Fa0/13 128.19 128 100 BLK 38 0404.0400.0001 128.19 Fa0/14 128.20 128 100 BLK 38 0404.0400.0001 128.20 Fa0/15 128.21 128 100 BLK 38 0404.0400.0001 128.21 Fa0/16 128.22 128 100 BLK 38 0404.0400.0001 128.22 Fa0/17 128.23 128 100 BLK 38 0404.0400.0001 128.23 Fa0/18 128.24 128 100 BLK 38 0404.0400.0001 128.24 Fa0/19 128.25 128 100 BLK 38 0404.0400.0001 128.25 Fa0/20 128.26 128 100 BLK 38 0404.0400.0001 128.26 Fa0/21 128.27 128 100 BLK 38 0404.0400.0001 128.27 Port Designated Name Port ID Prio Cost Sts Cost Bridge ID Port ID ------- ------- ---- ---- --- ---- -------------- ------- Fa0/22 128.28 128 100 BLK 38 0404.0400.0001 128.28 Fa0/23 128.29 128 100 BLK 38 0404.0400.0001 128.29 Fa0/24 128.30 128 100 BLK 38 0404.0400.0001 128.30 Hello Time 2 sec Max Age 20 sec Forward Delay 15 secThe table below describes the significant fields shown in the display.
Table 6 show spanning-tree brief Field Descriptions Field
Description
VLAN1
VLAN for which spanning-tree information is shown.
Spanning tree enabled protocol
Type of spanning tree (IEEE, IBM, CISCO).
ROOT ID
Indicates the root bridge.
Priority
Priority indicator.
Address
MAC address of the port.
Hello Time
Amount of time, in seconds, that the bridge sends bridge protocol data units (BPDUs).
Max Age
Amount of time, in seconds, that a BPDU packet should be considered valid.
Forward Delay
Amount of time, in seconds, that the port spends in listening or learning mode.
Port Name
Interface type and number of the port.
Port ID
Identifier of the named port.
Prio
Priority associated with the port.
Cost
Cost associated with the port.
Sts
Status of the port.
Designated Cost
Designated cost for the path.
Designated Bridge ID
Bridge identifier of the bridge assumed to be the designated bridge for the LAN associated with the port.
The following is sample output from the showspanning-treevlan1command:
Router# show spanning-tree vlan 1 Spanning tree 1 is executing the IEEE compatible Spanning Tree protocol Bridge Identifier has priority 32768, address 00e0.1eb2.ddc0 Configured hello time 2, max age 20, forward delay 15 Current root has priority 32768, address 0010.0b3f.ac80 Root port is 5, cost of root path is 10 Topology change flag not set, detected flag not set, changes 1 Times: hold 1, topology change 35, notification 2 hello 2, max age 20, forward delay 15 Timers: hello 0, topology change 0, notification 0 Interface Fa0/1 in Spanning tree 1 is down Port path cost 100, Port priority 128 Designated root has priority 32768, address 0010.0b3f.ac80 Designated bridge has priority 32768, address 00e0.1eb2.ddc0 Designated port is 1, path cost 10 Timers: message age 0, forward delay 0, hold 0 BPDU: sent 0, received 0The table below describes the significant fields shown in the display.
Table 7 show spanning-tree vlan Field Descriptions Field
Description
Spanning tree
Type of spanning tree (IEEE, IBM, CISCO).
Bridge Identifier
Part of the bridge identifier and taken as the most significant part for bridge ID comparisons.
address
Bridge MAC address.
Root port
Identifier of the root port.
Topology change
Flags and timers associated with topology changes.
The following is sample output from the showspanning-treeinterfacefastethernet0/3command:
Router# show spanning-tree interface fastethernet0/3 Interface Fa0/3 (port 3) in Spanning tree 1 is down Port path cost 100, Port priority 128 Designated root has priority 6000, address 0090.2bba.7a40 Designated bridge has priority 32768, address 00e0.1e9f.4abf Designated port is 3, path cost 410 Timers: message age 0, forward delay 0, hold 0 BPDU: sent 0, received 0Examples
This example shows how to display a summary of interface information:
Router# show spanning-tree VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 4097 Address 0004.9b78.0800 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 4097 (priority 4096 sys-id-ext 1) Address 0004.9b78.0800 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 15 Interface Port ID Designated Port ID Name Prio.Nbr Cost Sts Cost Bridge ID Prio.Nbr ---------------- -------- --------- --- --------- -------------------- -------- Gi2/1 128.65 4 LIS 0 4097 0004.9b78.0800 128.65 Gi2/2 128.66 4 LIS 0 4097 0004.9b78.0800 128.66 Fa4/3 128.195 19 LIS 0 4097 0004.9b78.0800 128.195 Fa4/4 128.196 19 BLK 0 4097 0004.9b78.0800 128.195 Router#The table below describes the fields that are shown in the example.
Table 8 show spanning-tree Command Output Fields Field
Definition
Port ID Prio.Nbr
Port ID and priority number.
Cost
Port cost.
Sts
Status information.
This example shows how to display information about the spanning tree on active interfaces only:
Router# show spanning-tree active UplinkFast is disabled BackboneFast is disabled VLAN1 is executing the ieee compatible Spanning Tree protocol Bridge Identifier has priority 32768, address 0050.3e8d.6401 Configured hello time 2, max age 20, forward delay 15 Current root has priority 16384, address 0060.704c.7000 Root port is 265 (FastEthernet5/9), cost of root path is 38 Topology change flag not set, detected flag not set Number of topology changes 0 last change occurred 18:13:54 ago Times: hold 1, topology change 24, notification 2 hello 2, max age 14, forward delay 10 Timers: hello 0, topology change 0, notification 0 Router#This example shows how to display the status of spanning-tree BackboneFast:
Router# show spanning-tree backbonefast BackboneFast is enabled BackboneFast statistics ----------------------- Number of transition via backboneFast (all VLANs) : 0 Number of inferior BPDUs received (all VLANs) : 0 Number of RLQ request PDUs received (all VLANs) : 0 Number of RLQ response PDUs received (all VLANs) : 0 Number of RLQ request PDUs sent (all VLANs) : 0 Number of RLQ response PDUs sent (all VLANs) : 0 Router#This example shows how to display information about the spanning tree for this bridge only:
Router# show spanning-tree bridge VLAN1 Bridge ID Priority 32768 Address 0050.3e8d.6401 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec . Router#This example shows how to display detailed information about the interface:
Router# show spanning-tree detail VLAN1 is executing the ieee compatible Spanning Tree protocol Bridge Identifier has priority 4096, address 00d0.00b8.1401 Configured hello time 2, max age 20, forward delay 15 We are the root of the spanning tree Topology change flag not set, detected flag not set Number of topology changes 9 last change occurred 02:41:34 ago from FastEthernet4/21 Times: hold 1, topology change 35, notification 2 hello 2, max age 20, forward delay 15 Timers: hello 1, topology change 0, notification 0, aging 300Port 213 (FastEthernet4/21) of VLAN1 is forwarding Port path cost 19, Port priority 128, Port Identifier 128.213. Designated root has priority 4096, address 00d0.00b8.1401 Designated bridge has priority 4096, address 00d0.00b8.1401 Designated port id is 128.213, designated path cost 0 Timers: message age 0, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 4845, received 1 Router#This example shows how to display information about the spanning tree for a specific interface:
Router# show spanning-tree interface fastethernet 5/9 Interface Fa0/10 (port 23) in Spanning tree 1 is ROOT-INCONSISTENT Port path cost 100, Port priority 128 Designated root has priority 8192, address 0090.0c71.a400 Designated bridge has priority 32768, address 00e0.1e9f.8940This example shows how to display information about the spanning tree for a specific bridge group:
Router# show spanning-tree 1 UplinkFast is disabled BackboneFast is disabled Bridge group 1 is executing the ieee compatible Spanning Tree protocol Bridge Identifier has priority 32768, address 00d0.d39c.004d Configured hello time 2, max age 20, forward delay 15 Current root has priority 32768, address 00d0.d39b.fddd Root port is 7 (FastEthernet2/2), cost of root path is 19 Topology change flag set, detected flag not set Number of topology changes 3 last change occurred 00:00:01 ago from FastEthernet2/2 Times: hold 1, topology change 35, notification 2 hello 2, max age 20, forward delay 15 Timers: hello 0, topology change 0, notification 0 bridge aging time 15 Port 2 (Ethernet0/1/0) of Bridge group 1 is down Port path cost 100, Port priority 128 Designated root has priority 32768, address 0050.0bab.1808 Designated bridge has priority 32768, address 0050.0bab.1808 Designated port is 2, path cost 0 Timers: message age 0, forward delay 0, hold 0 BPDU: sent 0, received 0 Router#This example shows how to display a summary of port states:
Router# show spanning-tree summary Root bridge for: Bridge group 1, VLAN0001, VLAN0004-VLAN1005 VLAN1013-VLAN1499, VLAN2001-VLAN4094 EtherChannel misconfiguration guard is enabled Extended system ID is enabled Portfast is enabled by default PortFast BPDU Guard is disabled by default Portfast BPDU Filter is disabled by default Loopguard is disabled by default UplinkFast is disabled BackboneFast is disabled Platform PVST Simulation is enabled Pathcost method used is long Name Blocking Listening Learning Forwarding STP Active ---------------------- -------- --------- -------- ---------- ---------- 1 bridge 0 0 0 1 1 3584 vlans 3584 0 0 7168 10752Blocking Listening Learning Forwarding STP Active ---------------------- -------- --------- -------- ---------- ---------- Total 3584 0 0 7169 10753 Router#This example shows how to display the total lines of the spanning-tree state section:
Router# show spanning-tree summary total Root bridge for:Bridge group 10, VLAN1, VLAN6, VLAN1000. Extended system ID is enabled. PortFast BPDU Guard is disabled EtherChannel misconfiguration guard is enabled UplinkFast is disabled BackboneFast is disabled Default pathcost method used is long Name Blocking Listening Learning Forwarding STP Active -------------------- -------- --------- -------- ---------- ---------- 105 VLANs 3433 0 0 105 3538 BackboneFast statistics ----------------------- Number of transition via backboneFast (all VLANs) :0 Number of inferior BPDUs received (all VLANs) :0 Number of RLQ request PDUs received (all VLANs) :0 Number of RLQ response PDUs received (all VLANs) :0 Number of RLQ request PDUs sent (all VLANs) :0 Number of RLQ response PDUs sent (all VLANs) :0 Router#This example shows how to display information about the spanning tree for a specific VLAN:
Router# show spanning-tree vlan 200 VLAN0200 Spanning tree enabled protocol ieee Root ID Priority 32768 Address 00d0.00b8.14c8 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32768 Address 00d0.00b8.14c8 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 Interface Role Sts Cost Prio.Nbr Status ---------------- ---- --- --------- -------- -------------------------------- Fa4/4 Desg FWD 200000 128.196 P2p Fa4/5 Back BLK 200000 128.197 P2p Router#The table below describes the fields that are shown in the example.
Table 9 show spanning-tree vlan Command Output Fields Field
Definition
Role
Current 802.1w role; valid values are Boun (boundary), Desg (designated), Root, Altn (alternate), and Back (backup).
Sts
Spanning-tree states; valid values are BKN* (broken)2, BLK (blocking), DWN (down), LTN (listening), LBK (loopback), LRN (learning), and FWD (forwarding).
Cost
Port cost.
Prio.Nbr
Port ID that consists of the port priority and the port number.
Status
Status information; valid values are as follows:
- P2p/Shr--The interface is considered as a point-to-point (resp. shared) interface by the spanning tree.
- Edge--PortFast has been configured (either globally using the defaultcommand or directly on the interface) and no BPDU has been received.
- *ROOT_Inc, *LOOP_Inc, *PVID_Inc and *TYPE_Inc--The port is in a broken state (BKN*) for an inconsistency. The port would be (respectively) Root inconsistent, Loopguard inconsistent, PVID inconsistent, or Type inconsistent.
- Bound(type)--When in MST mode, identifies the boundary ports and specifies the type of the neighbor (STP, RSTP, or PVST).
- Peer(STP)--When in PVRST rapid-pvst mode, identifies the port connected to a previous version of the 802.1D bridge.
2 For information on the *, see the definition for the Status field.This example shows how to determine if any ports are in the root-inconsistent state:
Router# show spanning-tree inconsistentports Name Interface Inconsistency -------------------- -------------------- ------------------ VLAN1 FastEthernet3/1 Root Inconsistent Number of inconsistent ports (segments) in the system :1 Router#Related Commands
Command
Description
spanning-tree backbonefast
Enables BackboneFast on all Ethernet VLANs.
spanning-tree cost
Sets the path cost of the interface for STP calculations.
spanning-tree guard
Enables or disables the guard mode.
spanning-tree pathcost method
Sets the default path-cost calculation method.
spanning-tree portfast (interface configuration mode)
Enables PortFast mode.
spanning-tree portfast bpdufilter default
Enables BPDU filtering by default on all PortFast ports.
spanning-tree portfast bpduguard default
Enables BPDU guard by default on all PortFast ports.
spanning-tree port-priority
Sets an interface priority when two bridges vie for position as the root bridge.
spanning-tree uplinkfast
Enables UplinkFast.
spanning-tree vlan
Enables the STP on a VLAN.
show udld
To display the administrative and operational Unidirectional Link Detection Protocol (UDLD) status, use the show udld command in user EXEC mode.
Command History
Release
Modification
12.2(14)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(18)SXD
This command was changed to include the neighbors keyword.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
If you do not enter an interface-id value, the administrative and operational UDLD status for all interfaces are displayed.
Examples
This example shows how to display the UDLD state for a single interface. The fields shown in the display are self-explanatory.
Router# show udld gigabitethernet2/2 Interface Gi2/2 --- Port enable administrative configuration setting: Follows device default Port enable operational state: Enabled Current bidirectional state: Bidirectional Current operational state: Advertisement Message interval: 60 Time out interval: 5 No multiple neighbors detected Entry 1 --- Expiration time: 146 Device ID: 1 Current neighbor state: Bidirectional Device name: 0050e2826000 Port ID: 2/1 Neighbor echo 1 device: SAD03160954 Neighbor echo 1 port: Gi1/1 Message interval: 5 CDP Device name: 066527791 Router#This example shows how to display neighbor information only. The fields shown in the display are self-explanatory.
Router# show udld neighbors Port Device Name Device ID Port-ID OperState -------- ------------------------------ ------------ ------- -------------- Gi3/1 SAL0734K5R2 1 Gi4/1 Bidirectional Gi4/1 SAL0734K5R2 1 Gi3/1 Bidirectional Router#
