© 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Implementing Spanning Tree Implementing RSTP

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v Rapid Spanning Tree Protocol

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v RSTP Port States

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v RSTP Port Roles

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v What Are Edge Ports? Will never have a switch connected to it Immediately transitions to forwarding Functions similarly to PortFast Configured by issuing the spanning-tree portfast command

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v RSTP Link Types

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v RSTP BPDU Flag Byte Use

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v RSTP Proposal and Agreement Process

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v Root and switch A synchronize. Ports on A come out of sync. Proposal or agreement takes place between A and B. Downstream RSTP Proposal and Agreement

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v RSTP Topology Change Mechanism

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v PVRST Implementation Commands Configuring spanning-tree mode rapid-pvst Verifying show spanning-tree vlan 101 Debugging debug spanning-tree

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v How to Implement Rapid PVRST

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v Verifying PVRST Display spanning tree mode is set to PVRST. Switch# show spanning-tree vlan 30 VLAN0030 Spanning tree enabled protocol rstp Root ID Priority Address 00d0.047b.2800 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority (priority sys-id-ext 30) Address 00d0.047b.2800 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 Interface Role Sts Cost Prio.Nbr Type Gi1/1 Desg FWD P2p Gi1/2 Desg FWD P2p Gi5/1 Desg FWD P2p

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v Summary RSTP provides faster convergence than 802.1D STP when topology changes occur. RSTP defines three port states: discarding, listening, and forwarding. RSTP defines five port roles: root, designated, alternate, backup, and disabled. Edge ports forward while topology changes occur. RSTP makes use of two link types–P2P and shared w uses the BPDU differently from 802.1D. Convergence results from the proposal and agreement process conducted switch by switch. The RSTP topology change notification process differs from 802.1D. Various commands are used to configure and verify PVRST. PVRST enables RSTP while still maintaining PVST.

© 2006 Cisco Systems, Inc. All rights reserved.BCMSN v