Dell 6200 manual Operation In The Network, April, Small Bridged Network, Single STP Topology

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OPERATION IN THE NETWORK

MSTP INTEROPERABILITY OF THE DELL™ POWERCONNECT™ 6200 SERIES SWITCHES WITH CISCO IOS AND CISCO CATOS-BASED SWITCHES

OPERATION IN THE NETWORK

In the following diagram of a small, 802.1d bridged network, STP is necessary to create an environment with full connectivity and without loops:

Figure 4: Small Bridged Network

Assume that bridge BrA is elected to be the Root Bridge, and Port Pt1 on bridge BrB and BrC are calculated to be the root ports for those bridges, Port Pt2 on bridge BrB and BrC would be placed into Blocking State. A loop-free topology would then exist. End stations in VLAN 10 could talk to other devices in VLAN 10 and end stations in VLAN 20 would only have a single path to communicate with other VLAN 20 devices. The logical single STP network topology would look something like this:

Figure 5: Single STP Topology

For VLAN 10, this Single STP Topology is fine and presents no limitations or inefficiencies. On the other hand, VLAN 20’s traffic pattern is inefficient. All frames from bridge BrB will have to traverse a path through bridge BrA before arriving at bridge BrC. If the ports Pt2 on bridge BrB and BrC could be used, these inefficiencies could be eliminated. MSTP does just that by allowing the configuration of MSTIs based upon a VLAN or groups of VLANs.

APRIL 2008

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Contents MSTP INTEROPERABILITY OF THE DELL POWERCONNECT 6200 SERIES SWITCHES Information in this document is subject to change without noticeWITH CISCO IOS OR CISCO CATOS BASED SWITCHES WEB CONFIGURATION CONTENTSVOICE VLAN CONFIGURATION CLI CONFIGURATIONAPRIL DELL POWERCONNECT 62XX MSTP FUNCTIONAL DESCRIPTIONActive Topology Admin Port StateSTP Port State MSTP Port StateFigure 2 Example FID to MSTI Allocation ACTIVE TOPOLOGY ENFORCEMENTFigure 3 Example Resultant VID to MSTI Allocation CONTROL PACKET BEHAVIOR MSTP CLI COMMANDSshow spanning-tree Figure 4 Small Bridged Network OPERATION IN THE NETWORKFigure 5 Single STP Topology Figure 6 Logical MSTP Environment Description SAMPLE SETUP AND CONFIGURATIONSCONFIGURING BRIDGE BrA CLI CommandCONFIGURING BRIDGE BrA WEB INTERFACE APRIL APRIL APRIL 10. Click Apply Changes 12. Click Show All to access the MSTP Settings Table CONFIGURING BRIDGE BrC CONFIGURING BRIDGE BrBCONFIGURING EDGE DEVICES show spanning-tree mst configuration ADDITIONAL MSTP STATUS INFORMATION Bridge BrA DellBridge BrB Dell Bridge BrC CiscoPriority Bridge BrA Dell APRILBridge BrB Dell ADDITIONAL INFORMATION AND SCALABILITY WITH MORE REGIONS Figure 7 Multiple MSTP Regions Figure 8 Multiple MSTP Region Interactions
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