FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide

Supporting FastIron Software Release 08.0.30

Part Number: 53-1003628-01

Displaying information about 802-1W

To display a summary of 802-1W, use the following command.

device#show
 802-1w  
--- VLAN 1 [ STP Instance owned by VLAN 1 ] ----------------------------
VLAN 1 BPDU cam_index is 2 and the IGC and DMA master Are(HEX) 0 1 2 3
Bridge IEEE 802.1W Parameters:
Bridge            Bridge  Bridge Bridge Force   tx
Identifier        MaxAge  Hello  FwdDly Version Hold
hex               sec     sec    sec            cnt
800000e080541700  20      2      15     Default 3
RootBridge        RootPath   DesignatedBri-    Root  Max  Fwd  Hel
Identifier        Cost       dge Identifier    Port  Age  Dly  lo
hex                          hex                     sec  sec  sec
800000e0804c9c00  200000     800000e0804c9c00  1     20   15   2
Port IEEE 802.1W Parameters:
      <--- Config Params -->|<-------------- Current state ----------------->
Port  Pri PortPath P2P Edge Role       State      Designa- Designated
Num       Cost     Mac Port                       ted cost bridge
1     128 200000   F   F    ROOT       FORWARDING 0        800000e0804c9c00
2     128 200000   F   F    DESIGNATED FORWARDING 200000   800000e080541700
3     128 200000   F   F    DESIGNATED FORWARDING 200000   800000e080541700
4     128 200000   F   F    BACKUP     DISCARDING 200000   800000e080541700

Syntax: show 802-1w [ vlan vlan-id]

The vlan vlan-id parameter displays 802.1W information for the specified port-based VLAN.

The show 802-1w command shows the information listed in the following figure.

Table 49 CLI display of 802.1W summary

Field

Description

VLAN ID

The port-based VLAN that owns the STP instance. VLAN 1 is the default VLAN. If you have not configured port-based VLANs on this device, all 802.1W information is for VLAN 1.

Bridge IEEE 802.1W parameters

Bridge Identifier

The ID of the bridge.

Bridge Max Age

The configured max age for this bridge. The default is 20.

Bridge Hello

The configured hello time for this bridge.The default is 2.

Bridge FwdDly

The configured forward delay time for this bridge. The default is 15.

Force-Version

The configured force version value. One of the following value is displayed:

  • 0 - The bridge has been forced to operate in an STP compatibility mode.
  • 2 - The bridge has been forced to operate in an 802.1W mode. (This is the default.)

txHoldCnt

The number of BPDUs that can be transmitted per Hello Interval. The default is 3.

Root Bridge Identifier

ID of the Root bridge that is associated with this bridge

Root Path Cost

The cost to reach the root bridge from this bridge. If the bridge is the root bridge, then this parameter shows a value of zero.

Designated Bridge Identifier

The bridge from where the root information was received.It can be from the root bridge itself, but it could also be from another bridge.

Root Port

The port on which the root information was received. This is the port that is connected to the Designated Bridge.

Max Age

The max age is derived from the Root port. An 802.1W-enabled bridge uses this value, along with the hello and message age parameters to compute the effective age of an RST BPDU.

The message age parameter is generated by the Designated port and transmitted in the RST BPDU. RST BPDUs transmitted by a Designated port of the root bridge contains a message value of zero.

Effective age is the amount of time the Root port, Alternate port, or Backup port retains the information it received from its peer Designated port. Effective age is reset every time a port receives an RST BPDU from its Designated port. If a Root port does not receive an RST BPDU from its peer Designated port for a duration more than the effective age, the Root port ages out the existing information and recomputes the topology.

If the port is operating in 802.1D compatible mode, then max age functionality is the same as in 802.1D (STP).

Fwd Dly

The number of seconds a non-edge Designated port waits until it can apply any of the following transitions, if the RST BPDU it receives does not have an agreed flag:

  • Discarding state to learning state
  • Learning state to forwarding state

When a non-edge port receives the RST BPDU it goes into forwarding state within 4 seconds or after two hello timers expire on the port.

Fwd Dly is also the number of seconds that a Root port waits for an RST BPDU with a proposal flag before it applies the state transitions listed above.

If the port is operating in 802.1D compatible mode, then forward delay functionality is the same as in 802.1D (STP).

Hello

The hello value derived from the Root port. It is the number of seconds between two Hello packets.

Port IEEE 802.1W parameters

Port Num

The port number shown in a slot#/port# format.

Pri

The configured priority of the port. The default is 128 or 0x80.

Port Path Cost

The configured path cost on a link connected to this port.

P2P Mac

Indicates if the point-to-point-mac parameter is configured to be a point-to-point link:

  • T - The link is configured as a point-to-point link.
  • F - The link is not configured as a point-to-point link. This is the default.

Edge port

Indicates if the port is configured as an operational Edge port:

  • T - The port is configured as an Edge port.
  • F - The port is not configured as an Edge port. This is the default.

Role

The current role of the port:

  • Root
  • Designated
  • Alternate
  • Backup
  • Disabled

Refer to Bridges and bridge port roles for definitions of the roles.

State

The port current 802.1W state. A port can have one of the following states:

  • Forwarding
  • Discarding
  • Learning
  • Disabled

Refer to Bridge port states and Edge port and non-edge port states.

Designated Cost

The best root path cost that this port received, including the best root path cost that it can transmit.

Designated Bridge

The ID of the bridge that sent the best RST BPDU that was received on this port.

To display detailed information about 802-1W, enter the 802-1w command.

device#show 802-1w detail 
======================================================================
VLAN 1 - MULTIPLE SPANNING TREE (MSTP - IEEE 802.1W) ACTIVE
======================================================================
BridgeId 800000e080541700, forceVersion 2, txHoldCount 3
Port 1 - Role: ROOT - State: FORWARDING
  PathCost 200000, Priority 128, AdminOperEdge F, AdminPt2PtMac F
  DesignatedPriority - Root: 0x800000e0804c9c00, Bridge: 0x800000e080541700
  ActiveTimers - rrWhile 4 rcvdInfoWhile 4
  MachineStates - PIM: CURRENT, PRT: ROOT_PORT, PST: FORWARDING
  TCM: ACTIVE, PPM: SENDING_STP, PTX: TRANSMIT_IDLE
  Received - RST BPDUs 0, Config BPDUs 1017, TCN BPDUs 0
Port 2 - Role: DESIGNATED - State: FORWARDING
  PathCost 200000, Priority 128, AdminOperEdge F, AdminPt2PtMac F
  DesignatedPriority - Root: 0x800000e0804c9c00, Bridge: 0x800000e080541700
  ActiveTimers - helloWhen 0
  MachineStates - PIM: CURRENT, PRT: DESIGNATED_PORT, PST: FORWARDING
  TCM: ACTIVE, PPM: SENDING_RSTP, PTX: TRANSMIT_IDLE
  Received - RST BPDUs 0, Config BPDUs 0, TCN BPDUs 0

Syntax: show 802-1w detail [ vlanvlan-id]

The vlan vlan-id parameter displays 802.1W information for the specified port-based VLAN.

The show spanning-tree 802.1W command shows the following information.

Table 50 CLI display of show spanning-tree 802.1W

Field

Description

VLAN ID

ID of the VLAN that owns the instance of 802.1W and whether or not it is active.

Bridge ID

ID of the bridge.

forceVersion

the configured version of the bridge:

  • 0 - The bridge has been forced to operate in an STP compatible mode.
  • 2 - The bridge has been forced to operate in an 802.1W mode.

txHoldCount

The number of BPDUs that can be transmitted per Hello Interval. The default is 3.

Port

ID of the port in slot#/port#format.

Role

The current role of the port:

  • Root
  • Designated
  • Alternate
  • Backup
  • Disabled

Refer to Bridges and bridge port roles for definitions of the roles.

State

The port current 802.1W state. A port can have one of the following states:

  • Forwarding
  • Discarding
  • Learning
  • Disabled

Refer to Bridge port states and Edge port and non-edge port states.

Path Cost

The configured path cost on a link connected to this port.

Priority

The configured priority of the port. The default is 128 or 0x80.

AdminOperEdge

Indicates if the port is an operational Edge port. Edge ports may either be auto-detected or configured (forced) to be Edge ports using the CLI:

  • T - The port is and Edge port.
  • F - The port is not an Edge port. This is the default.

AdminP2PMac

Indicates if the point-to-point-mac parameter is configured to be a point-to-point link:

  • T - The link is a point-to-point link
  • F - The link is not a point-to-point link. This is the default.

DesignatedPriority

Shows the following:

  • Root - Shows the ID of the root bridge for this bridge.
  • Bridge - Shows the ID of the Designated bridge that is associated with this port.

ActiveTimers

Shows what timers are currently active on this port and the number of seconds they have before they expire:

  • rrWhile - Recent root timer. A non-zero value means that the port has recently been a Root port.
  • rcvdInfoWhile - Received information timer. Shows the time remaining before the information held by this port expires (ages out). This timer is initialized with the effective age parameter. (Refer to the Max Age field in the Table 49.)
  • rbWhile - Recent backup timer. A non-zero value means that the port has recently been a Backup port.
  • helloWhen - Hello period timer. The value shown is the amount of time between hello messages.
  • tcWhile - Topology change timer. The value shown is the interval when topology change notices can be propagated on this port.
  • fdWhile - Forward delay timer.
  • mdelayWhile - Migration delay timer. The amount of time that a bridge on the same LAN has to synchronize its migration state with this port before another BPDU type can cause this port to change the BPDU that it transmits.

Machine States

The current states of the various state machines on the port:

  • PIM - State of the Port Information state machine.
  • PRT - State of the Port Role Transition state machine.
  • PST - State of the Port State Transition state machine.
  • TCM - State of the Topology Change state machine.
  • PPM - State of the Port Protocol Migration.
  • PTX - State of the Port Transmit state machine.

Refer to the "Port Role Selection state machines" section in Changes to port roles and states for details on state machines.

Received

Shows the number of BPDU types the port has received:

  • RST BPDU - BPDU in 802.1W format.
  • Config BPDU - Legacy configuration BPDU (802.1D format).
  • TCN BPDU - Legacy topology change BPDU (802.1D format).