Implementing Spanning Tree Implementing MSTP 2006 Cisco Systems
- Slides: 10
Implementing Spanning Tree Implementing MSTP © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -1
Multiple Spanning Tree Protocol Instance 1 maps to VLANs 1– 500 Instance 2 maps to VLANs 501– 1000 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -2
Extended System ID in Bridge ID Field © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -3
MST Regions MST configuration on each switch: • Name • Revision number • VLAN association table © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -4
Interacting Between MST Regions and 802. 1 D © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -5
Configuring MSTP Switch(config)#spanning-tree mst configuration • Enters MST configuration submode Switch(config-mst)#name • Sets the MST region name Switch(config-mst)#revision rev_num • Sets the MST configuration revision number Switch(config-mst)#instance inst vlan range • Maps the VLANs to an MST instance Switch(config)#spanning-tree mst instance_number root primary|secondary • Establishes primary and secondary roots for MST instance © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -6
Verifying MSTP Switch#show spanning-tree mst configuration • Displays MSTP configuration information Switch#show spanning-tree mst configuration Name [cisco] Revision 1 Instance Vlans mapped --------------------------------------0 11 -4094 1 1 -10 ---------------------------------------- © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -7
Verifying MSTP (Cont. ) Switch#show spanning-tree mst instance_number • Displays configuration information for a specific MSTP instance Switch#show spanning-tree mst 1 ###### MST 01 vlans mapped: 1 -10 Bridge address 00 d 0. 00 b 8. 1400 priority Root this switch for MST 01 Interface --------Fa 4/4 Fa 4/5 Fa 4/48 Role ---Back Desg Boun Sts --BLK FWD Cost ----1000 200000 Prio. Nbr -------240. 196 128. 197 128. 240 32769 (32768 sysid 1) Status ----------------P 2 p Bound(STP) Switch#clear spanning-tree detected-protocols [interface-id] • Forces renegotiation with neighboring switches during migration process © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -8
Summary • MSTP reduces the encumbrance of PVST by allowing a single instance of spanning tree to run for multiple VLANs. • An MST region is a group of MSTP switches that appears as a single virtual bridge to adjacent CST and MSTP regions. • Extended system ID ensures that VLAN ID or MSTP instance can be carried in the Bridge ID field of a BPDU. • An MSTP region requires an IST and an arbitrary number of MSTP instances as it connects to an 802. 1 Q network at the MST region border. • MSTP is configured with a unique set of commands. • MSTP implementation requires configuration and verification using specific configuration and show commands. © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -9
© 2006 Cisco Systems, Inc. All rights reserved. BCMSN v 3. 0— 3 -10
