EXP Computer S200 Type of Network Speed STPE Path Cost

Bridging 91

T0008-16F Release 5.2M

Spanning Tree Protocol Entity (STPE)

Determining Path

Costs Bridges use Path Cost to determine their Root Link. The range of Path Cost is 0 to

65535. The lower the path cost, the more likely this path will be used. Use This table

to determine the path costs for each type of link in your network.

For speeds not listed, interpolate to reasonable values. The valid range for path cost

is 0 to 65535 so that when values are determined, they should not be such that the

total path cost along any reasonable route adds up to more than 65535.

Some bridge manufacturers may list a different set of values for path cost incremen t.

It is important that the same rule be applied to all b ridges involved in the spanning

tree calculation.

Returning to the mesh network in Figure43, look at bridge B3: if the WAN lines are

all 19.2 kbps and the links are directly connected with a single SVC hop, then their

incremental cost for WAN links can be s et t o STPE Pat h Cost = 3536. Therefore, B3

will see messages from other bridge links result ing in the following cost to the root

bridge:

• From bridge 1 link 6: root is bridge 1, cost to root = 3536

• From bridge 4 link 8: root is bridge 1, cost to root = 7072 (3536+3536)

• From bridge 5 link 9: root is bridge 1, cost to root = 14154

(3536+10+3536+3536+3536)

Based on these numbers, B3 determines B1 to be the root bridge, because B1’s

bridge ID is lower than all reported root bridges (including B3’s own bridge ID). B3

also designates bridge link 6 as the root link since it has the least cost to the root.

Type of Network Speed STPE Path Cost

802.3 10 Mbps 10

802.5 4 Mbps 25

802.5 16 Mbps 6

serial 1.54 Mbps 65

serial 384 kbps 260

serial 56 kbps 1768

serial 19.2 kbps 3536

Contents

Main Notice Restricted Rights Notification for U.S. Government Users Restricted Rights Legend Notice Notice (continued) Proprietary Material Page Bridging Overview Figure 1. PathBuilder S200 Series Switch Bridge Combining Traffic from Serial Devices Page Page Page Bridging Features and Capabilities Figure 2. Example of Typical PathBuilder S200 Series Switch Bridging Application Ethernet LAN Figure 3. Frame Format for Ethernet Frames Figure 4. 802.3 Ethernet MAC Frame Format Example Figure 5. Ethernet Bridge Example Mixed LAN Bridging Figure 6. Example of Mixed LAN Bridging in PathBuilder S24x, 26x, and 27x Switch MAC Addressing LLC2 Local Termination Figure 7. Local Termination Example Autolearn for Local Termination Figure 8. Example of Local Termination Autolearn Filtering Spanning Tree Protocol Dual Ethernet LANs Basic Remote Bridging Examples Figure 9. PB S200s Connecting LANs via an X.25/Frame Relay Link Figure 10. Two-Port Bridges Connecting Multiple Token Ring LANs Figure 11. Example of Bridges in an SVC Arrangement Bridge Hardware Components in PathBuilder S200 Series Switches Figure 12. LAN Port Module and WAN Adapter Module (Logical View) Page Setting Up WAN Operation for Bridging Figure 13. Interface Connections Between WAN and LAN Page Configuring the PathBuilder S200 Series Switch for Bridging Operation Bridge Parameters Figure 14. Configure Bridge Parameters Page Page Page Bridge Link Parameters Figure 15. Configure Bridge Link Menu Page Page Page Page LAN Connection Table Figure 16. LAN Connection Table Menu Page Page Page Limiting Bridge Frame Sizes Figure 17. How Packet Size Affects Transit Delay Max Frame Size Line Speed Range (kbps) Configuring Translational Bridging 38 Bridging Configuring the PathBuilder S200 Series Switch for Bridging Operation Figure 18. Translational Bridging Example Figure 19. Translational Bridging Point-to-Point Example Bridge Frame Handling Configuring Source Route Bridging Operation Figure 20. LAN/WAN Bridge Links Used in PathBuilder S200 Series Switch LAN Network Page Connecting a Station to a Server in Source Route Bridging Figure 21. Example of a Station to Server Configuration Figure 22. Servers Destination MAC Address Not on LAN AAA Figure 23. All Route Explorer (ARE) Frame Searches the Network for the Server Figure 24. PathBuilder S200 Series Switch Transfers a Copy of ARE Frame to the Bridge Module Bridging 45 Configuring the PathBuilder S200 Series Switch for Bridging Operation Figure 25. WAN Adapter Transmits Each ARE Frame Across the WAN Figure 26. Server Responds with Specifically Routed TEST Frame If... Then... Transparent Bridging for Ethernet LANs Bridging 49 Transparent Bridging for Ethernet LANs Figure 27. How the Forwarder and Hardware Accelerator Process a Frame NO NO Figure 28. Relationship of Forwarder and Hardware Accelerator to LAN and WAN Handlers Page Page Forwarder Database and Spanning Tree Using Filters Page Transparent Bridge Configuration Parameters Figure 29. Transparent Bridge (TB) Forwarding Table Menu Bridge Filtering unnecessary MAC Address Filtering Parameter Action Parameter Action (continued) Parameter Value Action 60 Bridging Bridge Filtering Figure 30. MAC Address Filtering Action MAC Filtering Process Figure30 shows the MAC Filtering process. Figure 31. Example of a Frame Passing on a Bridge Link MAC Address Filtering Examples Figure 32. Example of Bridge Links Configured to Filter Selected MAC Address Frames Parameter Values Page Identifying Address Links for MAC Addressing Figure 33. Example of Address Links MAC Wildcard Filtering Figure 34. Example of How MAC Wildcard Filtering Works Configuring the MAC Address Filter Table Figure 35. MAC Address Filter Table Menu Page Page Page Protocol Filtering Configuring the Protocol Filter Table Figure 36. Configure Protocol Filter Table Menu Protocol SAP (hex value) Protocol OUI/IP (hex value) Page Figure 37. Protocol ID DSAP Located in LLC Field Figure 38. SNAP Protocol ID Parameter Action(s) NetBIOS Name Filtering Figure 39. NetBIOS Name Filtering Configuration Example Page Configuring NetBIOS Name Filtering Figure 40. Bridge Link Parameters Record Step Action Page Figure 41. Configure Bridge Menu Page Page Page NetBIOS Name Filtering Statistics Figure 42. Detailed Bridge Link Statistics NetBIOS Packet Formats Spanning Tree Protocol Entity (STPE) Configuration Menu STPE Control= AUTO STPE Control = MANUAL Page Page STPE Parameter Setting Considerations Figure 43. Example of a Bridge Network Figure 44. Example of Bridge ID and MAC Address 80-00 08-00-3E-02-53-8F MAC Address Bridge Priority Type of Network Speed STPE Path Cost Figure 45. Bridge Links Within Network Figure 46. Two Bridge Links Between B3 and B4 Page Spanning Tree Timers Page Bridge Forward Delay Timer Figure 47. Message Events in Network Page Page LLC2 Local Termination Figure 48. Local Termination Example Figure 49. Before Local Termination Example Figure 50. After Local Termination Example Figure 51. Example of Improper LT Configuration Figure 52. Example of Proper LT Configuration Type Name Description Figure 53. Example of LT Spoofing Local Termination spoofs: Local Termination does not spoof: Page Configuring Local Termination Step Action Step Action (continued) Result Page Page Page Page Page Deleting LT Configuration Records Mixed LAN Operation Figure 54. Example of Mixed LAN Bridging in PathBuilder S24x, 26x, and 27x Switch Page Step Action (continued) Result/Description Dual LAN Ethernet Figure 55. Example of Multiple Ethernet LAN Page Page LAN Server Subsystem Page Configuring the LSS Record Figure 56. LAN Server Subsystem (LSS) Record Menu Page Bridge Statistics Figure 57. The Bridge Statistics Menu Screen Spanning Tree Statistics Figure 58. Spanning Tree Status Page Bridging 127 Detailed Bridge Link Statistics Introduction Figure59 and Figure 60 show sample statistics screens. Figure 60. Detailed Bridge Link Statistics - Second Page Figure 59. Detailed Bridge Link Statistics - First Page Page Page Bridge Link Filter Summary Figure 61. Bridge Link Filter Summary Status Page Transparent Bridge Forwarding Table Statistics Figure 62. Transparent Bridge Forwarding Table Statistics Page Transparent Bridge Detailed Bridge Link Statistics Figure 63. Detailed Bridge Link Statistics (TB) - Second Page Term Description (continued) LAN Connection Statistics Figure 64. LAN Connection Statistics Menu Screen Figure 65. Detailed LAN Connection Statistics - First Page Figure 66. Detailed LAN Connection Statistics - Second Page Bridging 137 Page Page Figure 67. LAN Connection Summary Statistics LLC2 LT Session Summary Statistics Figure 68. Session Summary Statistics Screen Heading Description Page Bridging 143 LLC2 LT Detailed Session Statistics Figure 70. Detailed Session Statistics Screen - Page 2 Figure 69. Detailed Session Statistics Screen - Page 1 Heading Description Local Station Session Summary Heading Description (continued) Remote Spoofer Session Summary Heading Description (continued) Reset Statistics Page Appendix A Technical Support Country Data Rate Telephone Number Country Telephone Number Country Telephone Number Country Telephone Number Fax Number Index