show vpex topology

show vpex topology { port port_num} {summary | detail}


In an Extended Edge Switching environment, shows the bridge port extender (BPE) topology that is connected to the specified native cascade port.

Syntax Description

vpex Specifies Virtual Port Extender (VPEX).
port Specifies topology information for VPEX slots attached to a specified native VPEX cascade port on the controlling bridge (CB).
port_num Specifies the native VPEX cascade port number.
summary Includes connected VPEX slot numbers only. Default behavior when port is not specified.
detail Selects including VPEX slot interconnections. Default behavior when port is specified.


If a port is not specified, then summary (connected VPEX slot numbers only) information appears by default; if a port is specified, then detailed (VPEX slot interconnections) information appears by default.

Usage Guidelines

If a port is not entered or summary is selected, all topologies appear (summary mode). Only the native cascade port or MLAG and a list of slots appear in summary mode.

If a port is entered or detail is selected, detailed mode information appears. For a ring topology, the command shows both cascades that form a ring, including the dynamically created cascade ports and assigned backup roles. Thus the BPE in each cascade appears twice, one in each cascade.

Severed rings also appear as a pair of cascades with all upstream or cascade ports not being identified as backup. The cascades also indicate that the BPE has been dynamically created (configured) in its position in the cascade. If a native cascade port is not specified, then all topologies appear. Otherwise, only the topology connected to the CB‘s cascade port appears.

Possible ring states:
  • Idle—Ring has been detected, but its configuration has not yet started.
  • Init—The new ring is being defined. Dynamic cascade ports required for the redundancy provided by the ring feature are being created.
  • Configuring—The ring is being brought up.
  • Complete—Ring is fully operational and ready for recovery should a connection be severed.
  • Severed—The ring is operating as two cascades.
  • Rebalancing—The data plane of a ring is being rebalanced.

For slots configured using virtual MLAG, instead of the native cascade port, the MLAG ID appears.


The following example shows an 8-BPE ring that is formed with two MLAGs. The configured cascades were equal in length. In this case the ring was previously formed, but is now severed. MLAG 10 contains only local native cascade port 1:3. MLAG 11 contains only a native cascade port on the remote MLAG switch. Only slots that exist on the data plane portions of the long cascade remnants after the severance appear:
# show vpex topology port 1:3

Topology: Ring (severed)

  Native cascade port 1:3 (MLAG id 10)
          Upstream  Cascade         Cascade
    Slot  Port      Port     Flags  Slot
    ----  --------  -------  -----  -------
    108   49        50              109
    109   49        50          S   110
     ----  --------  -------  -----  -------

  MLAG peer “vpexpeer” id 11
          Upstream  Cascade         Cascade
    Slot  Port      Port     Flags  Slot
    ----  --------  -------  -----  -------
    115   49        50              114
    114   49        50              113
    113   49        50              112
    112   49        50         d    111
    111   50        49         d    110
    110   50        40         dS   109
    ----  --------  -------  -----  -------

 * - Port is a member of a load sharing group
 Flags: (b) Backup Upstream Port, (B) Backup Cascade Port,
        (c) Common ring link on this BPE
        (d) Dynamically Created Cascade Port,
        (E) Empty slot, (S) Severed ring link on this BPE.
The following example is a summary display of all topologies:
 # show vpex topology

  Topology: Ring (Complete)
    Native cascade port 1:1
      Slots: 100, 101, 102, 103, 104, 105, 106, 107
    Native cascade port 1:2
      Slots: 107, 106, 105, 104, 103, 102, 101, 100

  Topology: Ring (Severed)
    Native cascade port 1:3 (MLAG id 10)
      Slots: 108, 109
    MLAG ID 11
      Slots: 115, 114, 113, 112, 111, 110

  Topology: Cascade
    Native cascade port 1:4
      Slots: 116, 117, 118, 119, 120


This command was first available in ExtremeXOS 22.7.

Platform Availability

This command is available on ExtremeSwitching 5420 and 5520 series switches.