Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 380)

350 Multi-Service IronWare Switching Configuration Guide
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PVST or PVST+ compatibility
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Brocade(config-vlan-10)#fast uplink-span ethernet 8/1 to 8/2
Syntax: [no] fast uplink-span ethernet <port-no>
To check the status of Fast Uplink Span for a specified VLAN.
Brocade(config-vlan-2)#show span vlan 2 fast-uplink-span
STP instance owned by VLAN 2
Global STP (IEEE 802.1D) Parameters:
VLAN Root Root Root Prio Max He- Ho- Fwd Last Chg Bridge
ID ID Cost Port rity Age llo ld dly Chang cnt Address
Hex sec sec sec sec sec
2 8000000011111111 0 Root 8000 20 2 1 15 29596 0 000011111111
Port STP Parameters:
Port Prio Path State Fwd Design Designated Designated
Num rity Cost Trans Cost Root Bridge
Hex
1/1/1 80 4 LISTENING 0 0 8000000011111111 8000000011111111
Syntax: show span vlan <vlan-id> fast-uplink-span
The VLAN <vlan-id> parameter displays Fast Uplink Span information for the specified VLAN.
PVST or PVST+ compatibility
Brocade’s support for Cisco’s Per VLAN Spanning Tree plus (PVST+) allows the Brocade device to
run multiple spanning trees (MSTP) while also interoperating with IEEE 802.1Q devices
1 . Ports
automatically detect PVST+ BPDUs and enable support for the BPDUs once detected.
When it is configured for MSTP, the Brocade device can interoperate with PVST.
Overview of PVST and PVST+
Per VLAN Spanning Tree (PVST) is a Cisco proprietary protocol that allows a Cisco device to have
multiple spanning trees. The Cisco device can interoperate with spanning trees on other PVST
devices but cannot interoperate with IEEE 802.1Q devices. An IEEE 802.1Q device has all its ports
running a single spanning tree. PVST+ is an extension of PVST that allows a Cisco device to also
interoperate with devices that are running a single spanning tree (IEEE 802.1Q).
The PVST+ support allows the Brocade device to interoperate with PVST spanning trees and the
IEEE 802.1Q spanning tree at the same time.
IEEE 802.1Q and PVST regions cannot interoperate directly but can interoperate indirectly through
PVST+ regions. PVST BPDUs are tunneled through 802.1Q regions, while PVST BPDUs for VLAN 1
(the IEEE 802.1Q VLAN) are processed by PVST+ regions.
Figure 63 shows the interaction of IEEE
802.1Q, PVST, and PVST+ regions.
1. Cisco user documentation for PVST or PVST+ refers to the IEEE 802.1Q spanning tree as the
Common Spanning Tree (CST).