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VDX in standalone mode is not negotiating STP/RSTP/PVST/RPVST root bridge roles with Netiron MLX/XMR/CER/CES.

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TitleVDX in standalone mode is not negotiating STP/RSTP/PVST/RPVST root bridge roles with Netiron MLX/XMR/CER/CES.
Symptoms
VDXin standalone modeis not negotiatingSTP/RSTP/PVST/RPVST root bridge roles with Netiron MLX/XMR/CER/CES.

The user configured the MLX to be RSTP root bridge for VLAN 61, and configuredthe VDXto be a non-root bridge for VLAN 61 with command:

protocol spanning-tree RSTP
Environment
Software Release: N/A
Fixed in Version: N/A
Cause

The VDX uses the IEEE standard for STP/RSTP, which defines a single instance of STP/RSTP for all VLANs configured on a switch. The MLX by default has a separate STP/RSTP instance for each VLAN (Per VLAN STP/RSTP), therefore the VDX will have to be configured to operate in PVST or RPVST mode. The MLX does not have to be configured for PVST, as it will automatically operate in PVST mode when it receives a PVST BPDU on its interface.

Also the VDX may be sending BPDUs using theMAC-address 0304.0800.0700, which the MLX will not process. In addition,the MLX may be sending tagged BPDUs using MAC-address 0180.c200.0000, which the VDX will not process.

VDX does not support tunneling non-standard BPDUs and thus IEEE BPDUs (0180:C200:0000) generated as tagged packets in STP/RSTP/MSTP modes may not be tunneled successfully across VCS fabric. However, VDX supports tunneling standards' based BPDUs such as untagged IEEE BPDUs and tagged or untagged PVST BPDUs (0100:0CCC:CCCD).

To interoperate with MLX,or non-brocade switches (Cisco, Juniper), the user should:

configure cisco bpdu-mac under interface level:

spanning-tree bpdu-mac 0100.0ccc.cccd

Resolution
VDX configuration for PVST/RPVST

Consider the following items when configuring PVST and RPVST on VDX:

Disabling the tagging of native VLANs is required on STP/RSTP/MSTP switches in standalone mode, otherwise PVST/RPVST does not converge and forms a loop on the native VLAN. This causes the tagged native VLAN data traffic is ignored and the native vlan untagged data is forwarded.

Disabling the tagging of native VLANs is required on edge ports in fabric cluster mode, otherwise PVST/RPVST does not converge and forms a loop on the native VLAN. This causes the tagged native VLAN data traffic is ignored and the native vlan untagged data is forwarded.

If a VLAN is configured with tagged ports that do not have PVST mode enabled on the interface and are connected to the VDXs, and RSTP is enabled under the VLAN (PVST), then BPDUs from the tagged ports that are received by the VDX are dropped.


Example VDX Config:

sw0(config)# no vlan dot1q tag native
sw0(config)# protocol spanning-tree rpvst

sw0# sho run int vlan 61
interface Vlan 61
shutdown

sw0# sho run int te 0/8
interface TenGigabitEthernet 0/8
no fabric isl enable
no fabric trunk enable
switchport
switchport mode trunk
switchport trunk allowed vlan all
no switchport trunk tag native-vlan
spanning-tree bpdu-mac 0100.0ccc.cccd
no shutdown

Example MLX Config:

(config)# no spanning-tree

(config)# sho run vlan | begin vlan 61
vlan 61
tagged ethe 4/18 ethe 4/20
rstp priority 4095

(config)# sho run int eth 4/18
interface ethernet 4/18
enable

(config)# sho span pvst-mode
PVST+ Enabled on:
Port Method
4/18 Set by auto-detect
4/20 Set by auto-detect

Display output to verify STP/RSTP is working between the VDX and MLX

VDX RSTP Display:

sw0# show spanning-tree vlan 61 br
VLAN 0061

Spanning-tree Mode: Rapid PVST Protocol

Root ID Priority 10000
Address 0212.1010.212c
Hello Time 2, Max Age 20, Forward Delay 15

Bridge ID Priority 12349
Address 0005.3344.bf59
Hello Time 2, Max Age 20, Forward Delay 15

Interface Role Sts Cost Prio Link-type Edge
---------------------------------------------------------------------
Te 0/8 ALT DSC 20000 128 P2P No

Te 0/10 RTPT FWD 20000 128 P2P No

MLX RSTP Display:

(config)# sho rstp vlan 61

VLAN 61 - RSTP instance 12
--------------------------------------------------------------------
RSTP (IEEE 802.1w) Bridge Parameters:

Bridge Bridge Bridge Bridge Force tx
Identifier MaxAge Hello FwdDly Version Hold
hex sec sec sec cnt
271002121010212c 20 2 15 Default 3

RootBridge RootPath DesignatedBridge Root Max Hel Fwd
Identifier Cost Identifier Port Age lo Dly
hex hex sec sec sec
271002121010212c 0 271002121010212c Root 20 2 15

RSTP (IEEE 802.1w) Port Parameters:

|---------------Config Params--------------|------------------Current state--------------------|
Port Pri PortPath P2P Edge Role State Designa- Designated
Num Cost Mac Port ted cost bridge
4/18 128 20000 F F DESIGNATED FORWARDING 0 271002121010212c
4/20 128 20000 F F DESIGNATED FORWARDING 0 271002121010212c

Additional notes

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