![CCNP BCMSN Module 328/76
Switch (enable)set spantree root [secondary] <vlans> [dia
network_diameter] [hello hello_time]
Modifying the Root Selection
Setting the spantree root determines which
device is more likely to become the root bridge.](https://image.slidesharecdn.com/chap3-140825035916-phpapp02/75/Managing-Redundant-Links-Inter-VLAN-Routing-28-2048.jpg)
![CCNP BCMSN Module 336/76
Switch (enable) set spantree fwddelay delay [vlan]
Switch (enable) set spantree maxage agingtime [vlan]
Switch (enable) set spantree hello hello_interval
Modifying Default Timers
• Modify the default timers during spanning tree
instability.
• Use other methods to influence convergence.](https://image.slidesharecdn.com/chap3-140825035916-phpapp02/75/Managing-Redundant-Links-Inter-VLAN-Routing-36-2048.jpg)
Managing Redundant Links & Inter-VLAN Routing
This document discusses managing redundant links and spanning tree protocols. It describes spanning tree protocol (STP) operations including electing a root bridge, path cost calculations, port states and BPDU timers. It also covers spanning tree in VLAN environments, such as per-VLAN STP (PVST), and techniques for scaling STP, including modifying root selection, path costs, port priorities and timers. Other topics include Fast EtherChannel, PortFast and UplinkFast for improving convergence times.
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Managing Redundant Links & Inter-VLAN Routing
- 1. CCNP BCMSN Module31/76
- 2. CCNP BCMSN Module32/76 Managing Redundant Links Objectives Upon completion of this part, you will be able to perform the following tasks: • Determine the default spanning tree. • Improve spanning-tree convergence. • Ensure timely host access to the network. • Distribute traffic load on parallel links.
- 3. CCNP BCMSN Module33/76 • This chapter discusses the following topics: – Spanning-Tree Protocol – Spanning tree in a VLAN environment – Scaling the Spanning-Tree Protocol Managing Redundant Links
- 4. CCNP BCMSN Module34/76 • This section discusses the following topics: – Spanning-Tree Protocol • Issues and solutions • STP operations • Configuring STP – Spanning tree in a VLAN environment – Scaling Spanning-Tree Protocol Managing Redundant Links
- 5. CCNP BCMSN Module35/76 f2f2 b3 f3f3 b2 f4f4 b5 f5f5 b4 f4f4 b5 f5f5 b4 Access Layer VLANs: 2 3 2 3 4 5 4 5 f = forwarding b = blocking f2f2 f3f3 Distributio n Layer DSW 1 VLAN2 Link A Link B DSW 2 Ensuring Network Availability
- 6. CCNP BCMSN Module36/76 Station A Station B 1/1 1/2 Segment A Segment B Transparent Bridging A switch has the same characteristics as a transparent bridge.
- 7. CCNP BCMSN Module37/76 Station A Station B 2/2 2/11/1 1/2 Segment A Segment B What Is a Bridging Loop? Bridging loops occur any time there is a redundant path or loop in the bridge network.
- 8. CCNP BCMSN Module38/76 Station A Station B 2/2 2/11/1 1/2 Segment A Segment B Preventing Bridging Loops Reference Point X Bridging loops can be prevented by disabling the redundant path.
- 9. CCNP BCMSN Module39/76 Bridge Protocol Data Unit (BPDU) The BPDU is responsible for: • Electing a root bridge • Determining the location of loops • Blocking to prevent loops • Notifying the network of changes • Monitoring the state of the spanning tree
- 10. CCNP BCMSN Module310/76 Root Bridge Selection When First Booted: Bridge ID = Root ID
- 11. CCNP BCMSN Module311/76 Root Association What is the shortest path to the root bridge?
- 12. CCNP BCMSN Module312/76 Calculating Path Cost 100 100 10 10 Cost to the root from switch D is 20 Switch CRootSwitch A Switch BSwitch D • Path cost is a function of bandwidth of each path • Can be changed by a switch port cost parameter • Is determined by the sum of path costs between source and destination
- 13. CCNP BCMSN Module313/76 STP Port States ListeningListening ForwardingForwarding LearningLearningBlockingBlocking • Blocking • Listening • Learning • Forwarding • Disabled (off)
- 14. CCNP BCMSN Module314/76 BPDU Timers Timers are propagated from the root bridge. • Timers are used to prevent bridging loops. • Timers determine how long it will take Spanning-Tree Protocol to converge after a failure.
- 15. CCNP BCMSN Module315/76 Time Blockin g 20 Sec Listening Learning 15 Sec Forwarding 15 Sec Forward Delay Forward Delay Max-Age VLAN STP Timer Operation Using Default Values Spanning tree uses the timers as it passes through the Spanning-Tree Protocol states.
- 16. CCNP BCMSN Module316/76 1 2 1 RP DP DP RP DP DP 2 RP 1 2 21 3 (1) Switch D generates topology change BPDU. (2) Switch B regenerates topology change BPDU. A Network Topology Change ED 32768:0000000000 04 C Root-A 500 : 000000000001 32768:0000000000 02 B 32768:0000000000 03 NDP X
- 17. CCNP BCMSN Module317/76 STP Summary Ethernet 10BaseT Path Cost 100 Ethernet 10BaseT Path Cost 100 Ethernet 100BaseT Path Cost 10 Root Switch MAC Address 00-10-7b-00-00-08 Designated Switch MAC Address 00-10-7b-00-00-F9 S1 S2 S3 S4 Gigabit Ethernet Path Cost 1 • A switch performs spanning tree by default. • The default settings will elect a root bridge and calculate the shortest path from every switch to the root.
- 18. CCNP BCMSN Module318/76 Switch (enable) set spantree enable all Spantree enabled. Enabling Spanning Tree The Spanning-Tree can be enabled and disabled on a per-port basis.
- 19. CCNP BCMSN Module319/76 Verifying the STP Configuration Indicates This Device Is the RootSwitch (enable) show spantree VLAN 1 Spanning tree enabled Spanning tree type ieee Designated Root 00-50-bd-18-a8-00 Designated Root Priority 8192 Designated Root Cost 0 Designated Root Port 1/0 Root Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec Bridge ID MAC ADDR 00-50-bd-18-a8-00 Bridge ID Priority 8192 Bridge Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec Port Vlan Port-State Cost Priority Fast-Start Group-Method --------- ---- ------------- ----- -------- ---------- ------------ 2/1 1 forwarding 19 32 disabled 2/2 1 forwarding 19 32 disabled
- 20. CCNP BCMSN Module320/76 • This section discusses the following topics: Managing Redundant Links – Spanning-Tree Protocol – Spanning tree in a VLAN environment • Common spanning tree • Per-VLAN STP • Hybrid STP – Scaling Spanning-Tree Protocol
- 21. CCNP BCMSN Module321/76 – Common spanning tree • IEEE 802.1Q – Per-VLAN spanning tree • ISL – Hybrid • PVST+ ? ? ? ? ? ? How Many STPs in a Switched Network?
- 22. CCNP BCMSN Module322/76 VLAN1 Spannin g Tree • Increases network redundancy and minimizes recovery time VLAN1 Root Switch X VLAN2 Spannin g Tree X VLAN2 Root Switch Per-VLAN Spanning Tree (PVST)
- 23. CCNP BCMSN Module323/76 Root for Green VLAN Root for Red VLAN ISL Tagged Trunk • Allows control of forwarding paths on a subnet basis • Creates flexible design tools for traffic management • Provides simple techniques for Layer 2 redundancy Forwarding Port for Red VLAN Forwarding Port for Green VLAN Blocking Port for Green VLAN Blocking Port for Red VLAN PVST
- 24. CCNP BCMSN Module324/76 Common or Mono Spanning Tree Root Bridge Green Users Green Server Red Users Red Server = Backup Link = Forwarding Path Single spanning tree is not optimal for scalability or stability. Green Users Green Users Red UsersRed Users A B C H JIE G FD
- 25. CCNP BCMSN Module325/76 PVST+ Cisco PVST Region Common Spanning-Tree Region IEEE 802.1Q Trunks
- 26. CCNP BCMSN Module326/76 – Spanning-Tree Protocol – Spanning tree in a VLAN environment – Scaling Spanning-Tree Protocol • Root selection • Port priority and path cost • Fast EtherChannel • PortFast • UpLinkFast and BackBoneFast Managing Redundant Links This section discusses the following topics:
- 27. CCNP BCMSN Module327/76 – Optimal topology – Efficient workstation access – Load balancing on redundant links – Improving convergence time Scaling STP
- 28. CCNP BCMSN Module328/76 Switch (enable)set spantree root [secondary] <vlans> [dia network_diameter] [hello hello_time] Modifying the Root Selection Setting the spantree root determines which device is more likely to become the root bridge.
- 29. CCNP BCMSN Module329/76 Verifying the STP Configuration Switch (enable) show spantree 10 VLAN 10 Spanning tree enabled Spanning tree type ieee Designated Root 00-50-bd-18-a8-00 Designated Root Priority 8192 Designated Root Cost 0 Designated Root Port 1/0 Root Max Age 10 sec Hello Time 2 sec Forward Delay 7 sec Bridge ID MAC ADDR 00-50-bd-18-a8-00 Bridge ID Priority 8192 Bridge Max Age 10 sec Hello Time 2 sec Forward Delay 7 sec Port Vlan Port-State Cost Priority Fast-Start Group-Method --------- ---- ------------- ----- -------- ---------- ------------ 2/1 10 forwarding 19 32 disabled 2/2 10 forwarding 19 32 disabled
- 30. CCNP BCMSN Module330/76 Determining Path to the Root 100 10019 19 Path cost to root is 38. Switch C Root Switch A Switch B • Port cost • Path cost • Port priority Switch D 19 1/21/1 Path cost to root is 38.
- 31. CCNP BCMSN Module331/76 Switch (enable) set spantree portcost 1/2 10 Spantree port 1/2 path cost set to 10. Influencing Path Cost • Path cost is used to decide which ports should forward and which ports should block. • Path cost is a sum of port costs from the root bridge.
- 32. CCNP BCMSN Module332/76 Switch (enable) show spantree 10 1/2 Port Vlan Port-State Cost Priority Fast-Start Group-method --------- ---- ------------- ----- -------- ---------- ------------ 1/2 1 forwarding 10 32 disabled 1/2 100 forwarding 10 32 disabled 1/2 521 forwarding 10 32 disabled 1/2 522 forwarding 10 32 disabled 1/2 523 forwarding 10 32 disabled 1/2 524 forwarding 10 32 disabled 1/2 1003 not-connected 10 32 disabled 1/2 1005 not-connected 10 32 disabled Verifying Port Cost The port cost is found with the Spanning-Tree Protocol information of the port.
- 33. CCNP BCMSN Module333/76 Switch (enable) set spantree portpri 1/2 20 Bridge port 1/2 port priority set to 20. Setting Port Priority Port priority is another Spanning-Tree Protocol parameter that can be modified to influence the links that are forwarding or blocking.
- 34. CCNP BCMSN Module334/76 Switch (enable) set spantree portvlanpri 1/1 16 100-105 Switch (enable) set spantree portvlanpri 1/2 16 106-110 Setting VLAN Port Priority 1/1 1/2 VLANs 106-110VLANs 106-110 VLANs 100-105VLANs 100-105 Port VLAN priority allows load sharing on links by allowing VLANs to individually determine which links forward or block.
- 35. CCNP BCMSN Module335/76 Verifying VLAN Port Priority Use the show spantree command to verify port priority by VLAN. Switch (enable) set spantree portvlanpri 1/2 1 100 Switch (enable) show spantree 1/2 Port Vlan Port-State Cost Priority Fast-Start Group-method --------- ---- ------------- ----- -------- ---------- ------------ 1/2 1 blocking 19 32 disabled 1/2 100 forwarding 19 1 disabled 1/2 521 blocking 19 32 disabled 1/2 522 blocking 19 32 disabled 1/2 523 blocking 19 32 disabled 1/2 524 blocking 19 32 disabled 1/2 1003 not-connected 19 32 disabled 1/2 1005 not-connected 19 4 disabled
- 36. CCNP BCMSN Module336/76 Switch (enable) set spantree fwddelay delay [vlan] Switch (enable) set spantree maxage agingtime [vlan] Switch (enable) set spantree hello hello_interval Modifying Default Timers • Modify the default timers during spanning tree instability. • Use other methods to influence convergence.
- 37. CCNP BCMSN Module337/76 Fast EtherChanne l FastFast EtherChanneEtherChanne llFast Ethernet 4 Fast Ethernet 3 Fast Ethernet 2 Fast Ethernet 1 Fast EtherChanne l D E F A B C Parallel Fast Ethernet Links Fast and Gigabit EtherChannel allow for redundant links in a spanning tree environment by allowing the links to be treated as one link.
- 38. CCNP BCMSN Module338/76 D E F D Fast EtherChanne l Fast EtherChanne l D FE 1 FE 2 FE 3 FE … A->D B->D C->D etc. Flow Output Path FE 4 FE 3 FE 1 FE … D->A D->B D->C etc. Flow Output Path D D D D DD A B C D Load Distribution Algorithms Fast EtherChannel uses load distribution to share the links. Fast Ethernet 4 Fast Ethernet 3 Fast Ethernet 2 Fast Ethernet 1
- 39. CCNP BCMSN Module339/76 D E F A B C D Fast EtherChanne l Fast EtherChanne l Fast Ethernet 1 Fast Ethernet 2 D D D D DD A ggregation C ontrol P rotocols D PAg P PAg P Aggregation Control Protocols The Port Aggregation Protocol (PAgP) manages the Fast EtherChannel bundle. Fast Ethernet 4 Fast Ethernet 3 Fast Ethernet 2 Fast Ethernet 1 D
- 40. CCNP BCMSN Module340/76 D E F A B C Fast EtherChanne l Fast EtherChanne l Fast Ethernet 1 Fast Ethernet 2 EtherChannel Guidelines • Certain conditions must be met in order for the Fast EtherChannel bundle to begin operation. • Failure to meet these conditions may cause the ports to be automatically disabled. Fast Ethernet 4 Fast Ethernet 3 Fast Ethernet 2 Fast Ethernet 1
- 41. CCNP BCMSN Module341/76 Creating an EtherChannel Bundle Switch (enable) set port channel 1/1-2 on After ensuring that all pre-conditions have been met, configure the EtherChannel bundle.
- 42. CCNP BCMSN Module342/76 Verifying Fast EtherChannel Bundle Configuration Verify that the Port Channel bundle has been successfully created. Switch (enable) show port channel Port Status Channel Channel Neighbor Neighbor mode status device port ---- ------ ------- ------ ---------- --------- --------- 1/1 connected on channel WS-C2926 007475320 1/1 1/2 connected on channel WS-C2926 007475320 1/2 ----- ---------- --------- ----------- ------------------------- ----
- 43. CCNP BCMSN Module343/76 PortFastPortFastPortFastPortFast – Minimize server or workstation downtime – PortFast is for switched-user dedicated ports CC End-User PC What Is PortFast? PortFastPortFastPortFastPortFast
- 44. CCNP BCMSN Module344/76 UplinkFastUplinkFastUplinkFastUplinkFast – Minimize network downtime – UplinkFast is for fast spanning-tree uplink convergence in < 5 seconds for inter-switch connections – PortFast for switched-user dedicated ports New Forwarding Path for VLAN Red Normal Forwarding Link End-User PC What Is UplinkFast?
- 45. CCNP BCMSN Module345/76 Distribution Layer Distribution Layer User Workstations MAC Addresses “1” “2” “3” User Workstations MAC Addresses “1” “2” “3” Switch ASwitch A “Root” Switch“Root” Switch “Backup” Root Switch“Backup” Root Switch Link 1Link 1 Link 3Link 3 Direct Fault Detected Direct Fault Detected Indirect Fault Detected Indirect Fault Detected Direct Fault Detected Direct Fault Detected Resolved By UplinkFastResolved By UplinkFast Access LayerAccess Layer Link Fault OccursLink Fault Occurs Link 2Link 2 UplinkFast Operation
- 46. CCNP BCMSN Module346/76 Switch (enable) set spantree uplinkfast enable Enabling UplinkFast – UplinkFast affects all VLANs on the switch. – UplinkFast cannot be configured on an individual VLAN. Switch(config)#uplinkfast Set Command-Based Switch: Cisco IOS Command-Based Switch:
- 47. CCNP BCMSN Module347/76 Verifying UplinkFast Cisco IOS Command-Based Switch Switch (enable) show spantree uplinkfast Switch#show uplinkfast Switch#show uplinkfast statistics Set Command-Based Switch
- 48. CCNP BCMSN Module348/76 BackboneFast Overview Traditional STP STP with BackboneFast STP Blocked for Red Normal Forwarding Link STP Root STP Root RLQ Inquiry & Response Link Failure BackboneFast: Receipt of inferior BPDUs triggers root link query PDU
- 49. CCNP BCMSN Module349/76 Configuring BackboneFast Switch (enable) set spantree backbonefast Switch (enable) show spantree backbonefast Backbonefast is enabled.
- 50. CCNP BCMSN Module350/76 Visual Objective Primary Root UplinkFastUplinkFast UplinkFastUplinkFast 43 1 2 Backup Root Fast EtherChannel Spanning-Tree Domain
- 51. CCNP BCMSN Module351/76 Summary •In this part, you learned the following key points: – STP provides path redundancy while preventing undesirable loops in the network. – A single instance of STP runs on each VLAN. – PortFast causes an STP port to enter the forwarding state immediately. – UplinkFast provides fast convergence after an STP topology change and achieves load balancing between redundant links. – BackboneFast is initiated when a root port or blocked port receives an inferior BPDU from its designated bridge.
- 52. CCNP BCMSN Module352/76 Inter-VLAN Routing Objectives • Upon completion of this part, you will be able to perform the following tasks: – Identify the network devices required to effect inter-VLAN routing. – Configure a default gateway to ensure network reachability. – Configure a route processor to facilitate inter-VLAN routing.
- 53. CCNP BCMSN Module353/76 Inter-VLAN Routing •This chapter discusses the following topics: – Inter-VLAN routing issues – Distribution layer topology – Configuring inter-VLAN routing
- 54. CCNP BCMSN Module354/76 Inter-VLAN Routing •This section discusses the following topics: – Inter-VLAN routing issues •Isolated collision domains •Finding the route •Supporting multiple VLAN traffic – Distribution layer topology – Configuring inter-VLAN routing
- 55. CCNP BCMSN Module355/76 Problem: Isolated Broadcast Domains VLAN10 VLAN20 172.16.20.4 VLAN30 Because of their nature, VLANs inhibit communication between VLANs.
- 56. CCNP BCMSN Module356/76 Solution: Routing Between VLANs VLAN10 VLAN20 172.16.20.4 VLAN30 Communications between VLANs require a routing processor.
- 57. CCNP BCMSN Module357/76 Problem: Finding the Route VLAN10 Network 172.16.10.0 172.16.10.3 VLAN20 Network 172.16.20.0 172.16.20.4 I need to send this packet to 172.16.20.4. That address is not on my local segment. I need to send this packet to 172.16.20.4. That address is not on my local segment. Where can end-user stations send nonlocal packets?
- 58. CCNP BCMSN Module358/76 Solution: Defining a Default Gateway VLAN10 Network 172.16.10.0 172.16.10.3 VLAN20 Network 172.16.20.0 172.16.20.4 I know where network 172.16.20.0 is! I know where network 172.16.20.0 is! End-user stations send nonlocal packets to a default router. I will send the packet to my default router. I will send the packet to my default router.
- 59. CCNP BCMSN Module359/76 VLAN20VLAN10 Problem: Supporting Multiple VLAN Traffic VLAN30 I have three distinct streams of traffic destined for the same place! I have three distinct streams of traffic destined for the same place! ? ? File Server A 172.16.3.127 I need information from File Server A. I need information from File Server A. I need information from File Server A. I need information from File Server A. I need information from File Server A. I need information from File Server A. Multiple VLANs interfacing with a single route processor require multiple connections or VLAN trunking. ? ?
- 60. CCNP BCMSN Module360/76 VLAN6 0 VLAN10 VLAN30VLAN20 Solution: Multiple Links The router can support a separate interface for each VLAN.
- 61. CCNP BCMSN Module361/76 Solution: Inter-Switch Link The router can support a single ISL link for multiple VLANs. VLAN10 VLAN30VLAN20 Eth 3/0.1 3/0.2 3/0.3 3/0.4 VLAN60 ISL Link VLAN10 VLAN30VLAN20
- 62. CCNP BCMSN Module362/76 Inter-VLAN Routing •This section discusses the following topics: – Inter-VLAN routing fundamentals – Distribution switch topology •External route processors •Internal route processors – Configuring inter-VLAN routing
- 63. CCNP BCMSN Module363/76 Distribution Layer Route Processors Distribution Layer The distribution-layer device is a combination of a high-end switch and a route processor.
- 64. CCNP BCMSN Module364/76 External Route Processor Switch C Switch A Switch B VLAN41 Network 172.16.41.3 VLAN41 Network 172.16.41.4 VLAN42 Network 172.16.42.5 • An external Cisco high-end router and a Catalyst 5000 switch with an NFFC or NFFCII • Connected by multiple Ethernet connections or an ISL link
- 65. CCNP BCMSN Module365/76 Internal Route Processors Multilayer switches integrate Layer 2 and Layer 3 functionality in a single box. VLAN41 Network 172.16.41.4 VLAN42 Network 172.16.42.5 VLAN41 Network 172.16.41.3
- 66. CCNP BCMSN Module366/76 Internal Route Processors (cont.) RSM can reside in slots 2 through 12 of a Catalyst 5000 switch. RSM • RSFC is a daughter card on the Supervisor Engine IIG and IIIG. RSFC
- 67. CCNP BCMSN Module367/76 Inter-VLAN Routing •This section discusses the following topics: – Inter-VLAN routing fundamentals – Distribution layer topology – Configuring inter-VLAN routing • Locating and accessing the route processor • Configuring an interface • Defining a default gateway • Testing the link
- 68. CCNP BCMSN Module368/76 Locating the Route Processor Switch (enable) show module • Specifying a particular module number displays information on that module. • Not specifying a module number displays information on all modules installed in the system. Mod Module-Name Ports Module-Type Model Serial-Num Status --- ------------- ----- --------------------- --------- --------- ------- 1 0 Supervisor III WS-X5530 010821493 ok 2 24 10/100BaseTX Ethernet WS-X5225R 012145458 ok 3 1 Route Switch WS-X5302 006825295 ok
- 69. CCNP BCMSN Module369/76 Accessing the Route Processor Switch (enable) session 3 The session command eliminates the need to connect a terminal directly to the RSM console port. Logical Connection
- 70. CCNP BCMSN Module370/76 Identifying the Route Processor The host name uniquely identifies each route processor within the network. Router(config)#hostname RSM143 RSM143(config)#exit RSM143#
- 71. CCNP BCMSN Module371/76 Enabling an IP Routing Protocol Routing protocols determine optimal paths through the network and transport information across these paths. RSM141(config)#ip routing RSM141(config)#router igrp 1 RSM141(config-router)#network 172.16.0.0 172.16.10.0 172.16.30.0 172.16.20.0 Network 172.16.0.0
- 72. CCNP BCMSN Module372/76 Configuring a VLAN Interface on an Internal Route Processor RTR144(config)#interface vlan41 RTR144(config-if)#ip address 172.16.10.3 255.255.255.0 RTR144(config-if)#exit RTR144(config)#interface vlan42 RTR144(config-if)#ip address 172.16.20.3 255.255.255.0 RTR144(config-if)#exit • The internal route processor automatically encapsulates packets using ISL. • Initial configuration requires a no shutdown command.
- 73. CCNP BCMSN Module373/76 RSM144(config)#interface fastethernet 0/1.1 RSM144(config-if)#encapsulation isl 10 RSM144(config-if)#ip address 172.16.10.3 255.255.255.0 RSM144(config-if)#exit RSM144(config)#interface fastethernet 0/1.2 RSM144(config-if)#encapsulation isl 20 RSM144(config-if)#ip address 172.16.20.3 255.255.255.0 RSM144(config-if)#exit Configuring a VLAN Interface on an External Route Processor • Subinterfaces allow for routing multiple data streams through a single physical interface. • Initial configuration requires a no shutdown command. Interface FA 0/1 Subinterface 0/1.1 Interface FA 0/1 Subinterface 0/1.2 VLAN10 VLAN20 Encapsulation Type and VLAN Number Slot Subinterface Number Port
- 74. CCNP BCMSN Module374/76 Defining a Default Gateway VLAN40 VLAN30 ASW31#config t Enter configuration commands, one per line. End with CNTL/Z ASW31(config)#ip default-gateway 172.16.30.163 ASW41#config t Enter configuration commands, one per line. End with CNTL/Z ASW41(config)#ip default-gateway 172.16.40.163 172.16.1.163 172.16.30.163 172.16.40.163 Default Gateway 172.16.1.163 Default Gateway 172.16.1.163 Defining a default gateway facilitates inter-VLAN communications.
- 75. CCNP BCMSN Module375/76 Testing the Link PC41#ping 172.16.10.3 Sending 5, 100-byte ICMP Echos to 172.16.10.3, time out is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max 0/0/0/ ms The ping command tests connectivity to remote hosts.
- 76. CCNP BCMSN Module376/76 Summary • In this chapter, you learned the following key points: – Inter-VLAN routing is a requirement to enable communication between devices in separate VLANs. – Most devices are configured with the IP address of a default router to which all nonlocal network packets are sent. – The Inter-Switch Link (ISL) protocol is used to facilitate multiple VLAN traffic over a single link. – The distribution layer routing processor can be an internal or external router/switch topology.
Editor's Notes
- #3 &lt;number&gt; Purpose: Present the chapter objectives Timing: This chapter takes approximately 2 hours to present. Lab: This section has a lab exercise at the end and it takes approximately 1 hour. NOTE: The instructor will have to closely coordinate the actions in this lab as the students must form bigger groups as the work is being on the distribution switches. Emphasize: The chapter objectives describe what tasks and knowledge the students will be taught and need to demonstrate during the lab exercise. Transition: Lets get started!
- #4 &lt;number&gt; Purpose: The purpose of this slide is to break down the major categories that will be discussed in the module. Each section will be broken down into further detail as you start the section. Emphasize: Bulleted items and those that are discussed in this course, refer students to CCO for information not covered in this course. Some technologies that are covered in this course are Cisco unique such as Uplink Fast and BackBone Fast Transition: Lets look at some more.
- #5 &lt;number&gt; Purpose: We will start by defining the default behavior of Spanning Tree. This will enable students to recognize why scaling is important and to also recognize some of the techniques that might be used for scaling. Emphasize: Bulleted items and those that are discussed in this course, refer students to CCO for information not covered in this course. A good reference material for Spanning Tree is Radia Perlman’s Interconnections:Bridges and Routers. Transition: Lets look at some more.
- #6 &lt;number&gt; Purpose: This is an introductory slide to prepare students for the fact that redundant connections in the Switch Block are very necessary in order to provide a redundant, fault-tolerant network. We will be discussing the challenges of redundant connections in a Layer 2 network and the solutions to those challenges. Emphasize: The instructor should take the students through some of the possible scenarios that are on the slide. Emphasize the possibilities for disaster if the physical redundancy was not already in place and how that is only a partial solution. Bridging and switching are terms that are used interchangeably in this chapter. For the purposes of Spanning Tree they are considered to be the same thing. Transition: We are going to start with a overview of transparent bridging and look at what happens when a redundant link causes a loop.
- #7 &lt;number&gt; Purpose: To facilitate a discussion of the characteristics of Transparent Bridging Emphasize: Discuss the characteristics of transparent bridging without Spanning Tree There are other types of bridging available, most notably Source Route Bridging. This course will focus only on transparent bridging as it focuses only on Ethernet. Transition: Now that we have discussed the default behavior of transparent bridging lets look at what happens when a redundant link is created.
- #8 &lt;number&gt; Purpose: To facilitate a discussion of what happens during a bridging loop Emphasize: Start a broadcast packet like an ARP request at Station A and walk the students through the behavior of the bridge Emphasize that the bridge’s understanding of the location of Station A will be looping from port to port on the bridge Emphasize that just as bad, if not worse, is the fact that the broadcast will be re-created endlessly by the switch. Transition: How did the industry solve this problem? Spanning Tree Protocol
- #9 &lt;number&gt; Purpose: A look at the solution to the problem of redundant links in a transparent bridge environment. Emphasize: There could be several solutions to the redundant link problem. The solution chosen at the time was to choose a reference point, trace all paths back to the reference point and then put the redundant link in a standby state. This is the Spanning Tree protocol. Transition: Let’s look at how Spanning Tree does this. We will start with the basic unit of communication for Spanning Tree which is the BPDU or Bridge Protocol Data Unit.
- #10 &lt;number&gt; Purpose: The purpose of this slide is to begin the presentation on the mechanics of the Spanning Tree Protocol Emphasize: The contents of the BPDU. A significant field not explained in the text is flags which contain the topology change and topology change acknowledgement. The Root ID, Bridge ID, and Port ID are all made up of two fields. The first portion is the priority. 2 bytes are used for the priority for the Root ID and the Bridge ID, 1 byte is used for the Port ID. This is actually the port priority that is modified later in the section. Introduce the basics of the Spanning Tree Protocol here. We will then at each one of them in-depth. Transition: The first major step of Spanning Tree is the election of the Root Bridge.
- #11 &lt;number&gt; Purpose: To discuss the Root Bridge election process Emphasize: The Root ID and Bridge ID are actually 2 different components. The two components are the priority of the bridge and the MAC address that identifies the bridge. When a switch initially boots it assumes that it is the Root Bridge until it sees a BPDU with a Root Bridge ID that is lower. It then sets its Root Bridge ID to the lower number and begins to listen to BPDUs in order to trace paths back to that Root Bridge. Transition: The next step after the election of the Root Bridge is to trace paths back to the Root Bridge and to determine the least cost path.
- #12 &lt;number&gt; Purpose: To discuss how the shortest path to the Root Bridge is traced. Emphasize: The Port ID is actually a 1 byte port priority and a 1 byte port id. If a bridge receives two BPDU messages (BPDU1 and BPDU2) it will go through the following decision process: If the Root ID’s are equal then a BPDU with a lower path cost is considered to be better. Path cost is effectively a sum of all port costs. If Root ID’s and path costs are equal then the BPDU that is begin transmitted from the bridge with the Bridge ID is preferred. This would be in the case of two equal cost paths to the Root Bridge through different Designated Bridges. If Root ID’s, path costs, and Bridge ID’s are equal (as in parallel paths), the port identifier serves as the tiebreaker. The port identity is configured by the transmitting bridge which places a port number in the BPDU. Emphasize that the port identifier is made up of a 1 byte port priority and a 1 byte port id of the transmitting bridge. Transition: Calculating the path cost and port priority.
- #13 &lt;number&gt; Purpose: To continue the discussion of how a bridge determines the path that it will use to get to the Root Bridge. Emphasize: Different hardware and different versions of software use different costs for bandwidths. Transition: Now that we have looked at how it chooses the best path to the Root let’s look at the states of the port as it waits for this process to be completed.
- #14 &lt;number&gt; Purpose: Provide an introduction to the various STP states so that the students will comprehend them. Emphasize: The states of STP operation are the building blocks of its operation and they play a strong role in understanding the concepts discussed later in this chapter. Emphasize that only through the use of Cisco specific technology can STP immediately enter forwarding mode. Transition: How long does it stay in each of these states? Determine by timers that are propagated by the Root Bridge.
- #15 &lt;number&gt; Purpose: To discuss the timers used by the Spanning Tree protocol Emphasize: The purpose of each of the timers. The impact of the timers on network convergence Timers are propagated from the Root Bridge Why timers are so important to Spanning Tree. (To prevent temporary bridging loops from occurring).
- #16 &lt;number&gt; Purpose: To show how the timers are used during the states of a port in Spanning Tree Emphasize: Transition: Now that we have discussed how a switch associates itself when it is first booted let’s look at what happens when the network changes in a stable spanning tree environment.
- #17 &lt;number&gt; Purpose: To discuss the process that occurs during a topology change in the network. Emphasize: The steps of topology change notification in Spanning Tree Switches age out entries in their cache very quickly during times of topology change. Entries age out after the fwddelay timer has expired, not the 5 minutes which is the default. Transition: Summarize the default behavior of Spanning Tree
- #18 &lt;number&gt; Purpose: To provide a summary of the Spanning Tree Protocol’s default behavior Emphasize: Transition: Commands for enabling and verifying spanning tree
- #19 &lt;number&gt; Purpose: To show spanning tree commands Emphasize: Spanning Tree is enabled by default. Transition: Verify Spanning Tree
- #20 &lt;number&gt; Purpose: Verify Spanning Tree Emphasize: Fields in the output Transition: We are now going to discuss Spanning Tree in a VLAN environment
- #21 &lt;number&gt; Purpose: Outline the subsection on VLANs and STP Emphasize: Bulleted items and those that are discussed in this course, refer students to CCO for information not covered in this course. Transition: Lets look at some more.
- #22 &lt;number&gt; Purpose: Outline the different methods of supporting Spanning Tree and VLANs Emphasize: Bulleted items and those that are discussed in this course, refer students to CCO for information not covered in this course. Transition: Lets look at some more.
- #23 &lt;number&gt; Purpose: To discuss the Per-VLAN Spanning Tree approach of Cisco ISL. Emphasize: Emphasize the benefits as described in the bulleted list. This is a group of essential concepts that the students need to comprehend in order to grasp the functionality of STP as we move forward in technologies designed to improve its operation and increase redundancy. Transition: STP also allows for the network engineer to tune its operation as required for a unique implication in a network.
- #24 &lt;number&gt; Purpose: Introduce VLANs and Spanning Tree together as complimentary technologies Emphasize: Tree like structure once again is essential to proper STP operation Providing different STP Root switches per VLAN enable a more redundant network to be put in place. Benefits as detailed in the bulleted list Transition: The next method of Spanning Tree support for VLANs is called Mono or Common Spanning Tree
- #25 &lt;number&gt; Purpose: To show a Common or Mono Spanning Tree Emphasize: The STP implementation provided in this figure is sub-optimal Note: This is a good opportunity for the instructor to get students interacting in possible fixes for the design presented. I.e more than one instance of STP is needed but where should they be placed? What are the benefits of CST? Transition: The importance of proper SPT implementation cannot be stressed enough.
- #26 &lt;number&gt; Purpose: To discuss PVST+ which is the ability of Cisco CLI 4.x to support both CST and PVST by mapping information between the two types of Spanning Tree support. Emphasize: This is enabled by default. The student does not have to do any configuring in order to implement PVST+ Transition: Now that we understand how Cisco will implement Spanning Tree in the switch environment let’s look at ways that we can scale the STP.
- #27 &lt;number&gt; Purpose: Now its time to scale Spanning Tree in a large scale Campus Network Emphasize: Bulleted items and those that are discussed in this course, refer students to CCO for information not covered in this course. Uplink Fast and BackBone Fast are Cisco unique technology Transition: Let’s look at each method.
- #28 &lt;number&gt; Purpose: A brief look at some of the goals of scaling STP. Emphasize: Transition: Lets look at some more.
- #29 &lt;number&gt; Purpose: Go over the command set to modify the bridge priority Emphasize: You may want to mention that this command merely modifies the priority of the bridge to make it more likely that it becomes the Root Bridge. It does not guarantee that it becomes the root bridge. The diameter portion of the root bridge. This modifies the default timer values to reflect the true diameter of the network. Timer values have been created based on a hello timer of 2 seconds and a diameter of 7 switches. The diameter is measured from the Root Bridge with the Root counting as the first switch. The Switch Block has a diameter of 2. Reflecting the correct diameter will allow the network to converge faster. Transition: Verify the Root Bridge selection.
- #30 &lt;number&gt; Purpose: Verify root bridge selection Emphasize: Output of the command including the timers that have been modified. Note that the other bridges will assume the timers of the Root Bridge but would give their timers under the Bridge Timer field. Transition: Now that we have selected the Root Bridge how could we modify the choice of the path to the Root.
- #31 &lt;number&gt; Purpose: To introduce the parameters that can be configured Emphasize: You may want to go back to the decision process that was discussed with the BPDUs. The most desirable BPDU is based on path cost, bridge ID, and then port id. It is recommended that these parameters not be changed lightly. Proper network design and proper placement of the Root Bridge are preferable to the modification of the parameters that are used in choosing a path. Transition: The parameters following will modify each of these fields in order to allow the network administrator to determine the path that data will take.
- #32 &lt;number&gt; Purpose: To discuss how to influence path cost in order to determine which path will be the least cost path to the Root. Emphasize: Command structure Transition:
- #33 &lt;number&gt; Purpose: The purpose of this slide is to discuss how to set the port cost Emphasize: Command structure Transition:
- #34 &lt;number&gt; Purpose: Discuss the port priority command Emphasize: This command is not frequently used. An example of its use would be a UTP FastEthernet connection and a fiber FastEthernet connection. If there cost were the same you might want the switch to prefer the fiber over the UTP. Transition: A better use of the port priority setting is to use the fact that Cisco supports PVST. This allows you to set the priority on a per-VLAN basis.
- #35 &lt;number&gt; Purpose: To provide the command set and an example of Port VLAN Priority. Emphasize: Command structure Port VLAN Priority allows for load distribution across switches. Transition: Verifying Port VLAN Priority
- #36 &lt;number&gt; Purpose: Command structure for verifying Port VLAN Priority Emphasize: Command structure Transition: Other parameters that can be modified include the default timers of STP.
- #37 &lt;number&gt; Purpose: Provide commands for modifying timers. Emphasize: Timers should not be modified unless there is a specific reason to do so such as times of Spanning Tree instability. Modify the timers using the diameter option on the Root Bridge instead. Be careful of setting the diameter too low. Doing so may cause temporary loops. Transition: Another method of handling load distribution is EtherChannel.
- #38 &lt;number&gt; Purpose: To introduce EtherChannel Emphasize: Links are treated as one by STP This is load distribution or sharing not load balancing Transition: Continue discussion of EtherChannel
- #39 &lt;number&gt; Purpose: To discuss the process of load sharing based on flow Emphasize: Transition:
- #40 &lt;number&gt; Purpose To discuss the Port Aggregation Protocol Emphasize PAgP is responsible for managing the bundle including the removal and addition of links. Transition Still more EtherChannel!
- #41 &lt;number&gt; Purpose: To go over the guidelines for implementing EtherChannel Emphasize: If the guidelines are not followed the channel will not be brought up and the ports will be disabled. May want to encourage people to set up the channel during off hours in case some of the guidelines are missed. Transition:
- #42 &lt;number&gt; Purpose: Provide the student with the basic information necessary to set up a two port EtherChannel bundle. Emphasize: Slide contents Transition: Lets look at another command
- #43 &lt;number&gt; Purpose: Provide the student with the basic information necessary to verify the EtherChannel configuration. Emphasize: Slide contents Transition: Lets look at another command
- #44 &lt;number&gt; Purpose: Introduce Port Fast Technology Emphasize: Port Fast may be necessary for a lot of workstations and servers to attach to the network properly. Port Fast should only be used on ports that connect to end devices. Transition: Port Fast improves the time to bring a port from blocked to forwarding when it is first activated. Now we are going to look at ways of improving the time to bring up a blocked or redundant link during times of network failure.
- #45 &lt;number&gt; Purpose: Introduce Uplink Fast technology Emphasize: Uplink Fast improves switch to switch convergence where as Port Fast improves host to switch convergence Transition: UpLink Fast will alter the STP states so that if configured the states will immediately move to forwarding.
- #46 &lt;number&gt; Purpose: Provide an example of the Uplink Fast in operation Emphasize: UplinkFast should not be run on the root bridge. The command will actually modify the bridge priority to attempt to prevent the bridge from becoming the root. UplinkFast creates an UplinkFast group of the ports that are redundant and currently blocked. If the forwarding port fails, UplinkFast will immediately move one of the blocked ports into a forwarding state. Fail-over time is approximately 3 seconds. Transition: Configuring UplinkFast
- #47 &lt;number&gt; Purpose: Provide real world examples regarding the configuration of UpLinkFast Emphasize: Command structure Transition: Uplink Fast is another method of increasing redundancy that compliments STP by enabling immediate state changes.
- #48 &lt;number&gt; Purpose: Provide real world examples regarding the configuration of UpLinkFast Emphasize: Command structure Transition: Uplink Fast is another method of increasing redundancy that compliments STP by enabling immediate state changes.
- #49 &lt;number&gt; Purpose: Provide a brief introductory overview of the BackboneFast Convergence feature and how it works when compared to traditional STP operation. Emphasize: This figure demonstration of how the operation of BackboneFast will benefit a networks operation by comparing and contrasting it with traditional STP operation. If a new switch is introduced into a shared-medium topology, BackboneFast is not activated. The new switch begins sending inferior BPDUs that indicate it is the Root switch. However, the other switches ignore these inferior BPDUs and the new switch learns that Switch B is the designated bridge to Switch A, the Root switch. Transition: Lets get started!
- #50 &lt;number&gt; Purpose: Provide real world examples regarding the configuration and troubleshooting of Backbone Fast. Emphasize: Backbone Fast needs to be globally configured Transition: Now lets do a Lab!
- #51 &lt;number&gt;
- #52 &lt;number&gt; Purpose: This is what the students should have learned in this chapter. Emphasize: Learning is good! Transition: Lets review the material.
- #53 &lt;number&gt; Purpose: This slide states the module objectives. Timing: The total amount of time to complete this chapter: Lesson—40-45 minutes Laboratory Exercises —1 hour Note: This section has a laboratory exercise at the end. Emphasize: Read or state each objective so each student has a clear understanding of the module objectives. Transition: Following is a signpost of the chapter topics.
- #54 &lt;number&gt; Purpose: This slide discusses what major topic areas are discussed in this chapter. Emphasize: Read or state each topic area so each student has a clear understanding what will be covered in the chapter. At the end of this module, the students will be able to: Transition: Following is a signpost of the topics covered in the first section “Inter-VLAN Routing Issues”
- #55 &lt;number&gt; Purpose: This slide signposts the topics covered in this section Emphasize: Read or state each topic so each student has a clear understanding of what is covered in this section Transition: Following is a discussion of problems that can occur with isolated workgroups.
- #56 &lt;number&gt; Purpose: This slide poses the problem of communicating between VLANs. Emphasize: Point out that VLANs, by their nature, are designed to keep data from traversing the VLAN borders. However, end users stations need to communicate with entities outside the VLAN borders. Use the example of end users in one VLAN needed to communicate with enterprise servers residing in a VLAN across the network core. Transition: Following introduces the solution.
- #57 &lt;number&gt; Purpose: This slide introduces routers as the solution to inter-VLAN communications. Emphasize: In switched networks, route processors are used to provide communications between VLANs. Before you can configure routing between VLANs, you must have defined the VLANs on the switches in your network. Refer to the Cisco Internetworking Design Guide and appropriate switch documentation for information on these topics. The Cisco Internetworking Design Guide is available from Cisco Press. Inter-VLAN Routing is discussed in the Cisco IOS Switching Services Configuration Guide located on the Cisco Documentation CD-ROM. Transition: Following begins the discussion of some problems that occur as result of inter-VLAN routing.
- #58 &lt;number&gt; Purpose: This slide introduces the problem of how to resolve routes between VLANs. Emphasize: Some network devices use routing tables to identify where to deliver packets outside of the local network segment. Even though it is not the responsibility of end user devices to route data, these devices still must be able to send data to addresses on subnets other than their own. Transition: Following begins the discussion of some problems that occur as result of inter-VLAN routing.
- #59 &lt;number&gt; Purpose: This slide discusses the solution of default gateways. Emphasize: IP hosts tend to be configured with a default gateway or configured to use Proxy ARP in order to find a router on their LAN. Convincing an IP host to change its router usually required manual intervention to clear the ARP cache or to change the default gateway. Transition: Following is a discussion of how multiple sources use a single router to communicate with a single source.
- #60 &lt;number&gt; Purpose: This slide discusses the problem of how to support multiple VLAN traffic to a single router. Emphasize: Transition: Following is a discussion of multiple links to single router.
- #61 &lt;number&gt; Purpose: This slide discusses the solution of multiple VLANs to a single router. Emphasize: Point out that multiple links may work in a small installation. However, as the number of VLANs per switch increases, so does the requirement for the number of interfaces on the route processor. Some VLANs may not require inter-VLAN routing on a regular basis, creating a situation where interfaces on the route processor are infrequently or under-utilized. Transition: Following is a discussion of ISL links to single router.
- #62 &lt;number&gt; Purpose: This slide discusses the solution of ISL. Emphasize: The Inter-Switch Link (ISL) protocol is used to inter-connect two VLAN-capable Fast Ethernet devices, such as the Catalyst 5000 or Cisco 7500 routers. The ISL protocol is a packet-tagging protocol that contains a standard Ethernet frame and the VLAN information associated with that frame. ISL is currently supported over Fast Ethernet links, but a single ISL link, or trunk, can carry traffic from multiple VLANs. The concept of ISL was discussed in the “Defining Common Workgroups” chapter. How to configure ISL links is discussed later in this chapter. Discuss the example in the SG. Transition: Following is a discussion of ISL links to single router.
- #63 &lt;number&gt; Purpose: This slide states the module objectives. Emphasize: Read or state each objective so each student has a clear understanding of the module objectives. Transition: Following is a discussion on the topology at the distribution layer.
- #64 &lt;number&gt; Purpose: This slide discusses the distribution layer. Emphasize: Point out that the distribution layer consists of a combination of high-end switches and route processors. The distribution layer is the demarcation between networks in the access layer and networks in the core. Transition: Following is a discussion of an external topology.
- #65 &lt;number&gt; Purpose: This slide discusses the external router topology. Emphasize: Point out that the student can use existing Cisco high-end routers in conjunction with the Netflow Feature Card (NFFC) or NFFCII on a Catalyst 5000 family switch to implement multilayer switching. The router must be directly attached to the Catalyst switch either by multiple Ethernet connections (1 per subnet) or by a Fast Ethernet connection using an Inter-Switch Link (ISL). The Cisco high-end routers supporting multilayer switching include the Cisco 7500, 7200, 4500, and 4700 series routers. These routers must have the MultiLayer Switch Protocol (MLSP) software and IOS 11.3.4 or later software installed to provide the Layer 3 services to the switch. Work through the example in the student guide. Transition: Following is a discussion of an internal topology.
- #66 &lt;number&gt; Purpose: This page discusses the external router topology. Emphasize: Cisco multilayer switch can be a Catalyst 5000 series switch equipped with a Cisco System Route Switch Module (RSM), or Route Switch Feature Card (RSFC). The multilayer switch can also be a Catalyst 6000/6500 series with a Multilayer Switch Module (MSM). The RSM or MSM is a router module running normal Cisco IOS router software. This router module plugs directly into the Catalyst series switch backplane. Note: The Catalyst series switch must contain at least 3 slots to house the Supervisor III module, the RSM, and a line card. Any other requirements, such as redundant supervisor engines or multiple line cards, would require a larger chassis. This course focuses on the RSM as this is the equipment used in the laboratory exercises. The command set for the RSM is identical with the 6000/6500 series. Transition: The following continues the discussion of the internal router
- #67 &lt;number&gt; Purpose: This page discusses the internal route processor. Emphasize: The RSM resides in slots 2-12. Slot 1 is reserved for the supervisor engine. Slot 2 may be used for a backup/redundant supervisor engine. Slot 13 is reserved for an ATM or 8510 module. The maximum number of RSM modules for the Catalyst 5500 switch is seven. However, this number may be reduced depending on the number of ATM modules present. You can use any combination of ATM and RSM modules as long as the total does not exceed seven The RSM interface to the Catalyst 5000 series switch backplane is through VLAN0 and VLAN1. VLAN 0 is mapped to channel 0 and VLAN 1 is mapped to channel 1. VLAN 0 is used for communication between the RSM and the Catalyst 5000 series switch and is not accessible to the user. VLAN 1 is the Catalyst 5000 series switch default VLAN. Additional VLANs are toggled between the two channels as they are created. Transition: The following is the signpost for the next section.
- #68 &lt;number&gt; Purpose: This slide states the section topics. Emphasize: Read or state each topic so each student has a clear understanding of the what is discussed in the next section Transition: Following discusses how to locate the route processor.
- #69 &lt;number&gt; Purpose: This slide gives the command to display the modules in the switch. Emphasize: The Catalyst 5000, 4000, 2926G, or 2926 series switches are multi-module systems. The show module command displays what modules are installed, as well as the MAC address ranges and version numbers for each module. Entering the show module command without specifying a module number displays information on all modules installed in the system. Specifying a particular module number displays information on that specific module. In this example, point out the route switch module is in slot 3. This example does not show the complete display due to space constraints on the slide. Point out the SG example shows the complete display. Transition: Following describes how to access the route processor module.
- #70 &lt;number&gt; Purpose: This slide gives the command to connect to the route processor module from the switch prompt. Emphasize: Use the session command to access the RSM from the switch prompt. The command requires you designate the module number. The module number is obtained by issuing the show module command on the switch. Once the session command executes, you are logged onto the route processor. At this point, you are in user EXEC command mode on the route processor and you have direct access only to the RSM with which you have established a session. The RSM supports only one session command at a time. To exit from the router CLI back to the switch CLI, enter the exit command at the Router&gt; prompt. Transition: Following describes how to uniquely identify each router.
- #71 &lt;number&gt; Purpose: This slide describes the command to uniquely identify the RSM. Emphasis: Naming your router helps to better manage the network by being able to uniquely identify each route processor within the network. The name of the route processor is considered to be the host name and is the name displayed at the system prompt. To clear the hostname, enter the no hostname command in global configuration mode. Do not expect case to be preserved. Upper- and lowercase characters look the same to many internet software applications. For more information, refer to RFC 1178, Choosing a Name for Your Computer. The name must also follow the rules for ARPANET host names. They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphens. Names must be 63 characters or fewer. For more information, refer to RFC 1035, Domain Names--Implementation and Specification. Transition: The following describes how to enable a routing protocol.
- #72 &lt;number&gt; Purpose: This slide describes the ip routing and network commands. Emphasis: Routing protocols determine optimal paths through internetworks using routing algorithms, and transport information across these paths. Point out the Advanced Cisco Router Configuration (ACRC) course discusses network routing and routing protocols in greater detail. The ip routing command assigns a routing protocol to a route processor The network command informs the routing protocol which interfaces will participate in the send and receiving of routing updates. The network number must identify a network to which the router is physically connected. Transition: Following begins the discussion of mapping VLANs to interfaces.
- #73 &lt;number&gt; Purpose: This slide describes creating a VLAN on an internal route processor. Emphasis: Configuring inter-VLAN routing on the RSM consists of two main procedures: Creating and configuring VLANs on the switch and assigning VLAN membership to switch ports. Creating and configuring VLAN interfaces for inter-VLAN routing on the RSM. A VLAN interface must be configured for each VLAN between which traffic is to be routed. VLANs are created at the switch level to group ports into virtual LANs. VLANs are controlled at the route processor level. Each VLAN that the RSM is routing appears as a separate virtual interface. The RSM has one global MAC address that applies to all interfaces on that device. When interfacing with a Catalyst 1900 switch, uniquely specify a MAC address for each RSM interface. The Catalyst 1900 switch does not store a direct VLAN/MAC address mapping in the CAM table. If you configure multiple links to the same RSM, problems can occur in the 1900 switch. For example, the Catalyst 1900 has two links to a single RSM. Because only one MAC address is designated for each VLAN, the Catalyst 1900 will record the last port data was sent out on in the CAM table and Spanning Tree will block the other link. However, if that link is an active link and data is sent out the second link, then the switch will update the CAM table and STP will block the first link, even though both links are valid. Transition: Following discusses configuring an external route processor interface.
- #74 &lt;number&gt; Purpose: This slide describes the commands to configure a multiple VLAN interface on an external route processor. Emphasis: On an external router, an interface can be logically divided into multiple, virtual subinterfaces. Subinterfaces provide a flexible solution for routing multiple data streams through a single physical interface. To accomplish this goal, you need to customize the subinterface to create the environment in which the subinterface is used. To define subinterfaces on a physical interface, perform the following tasks. Identify the interface Define the VLAN encapsulation Assign an IP address to the interface Transition: The following describes how to define a default gateway.
- #75 &lt;number&gt; Purpose: This slide describes the command to define a default gateway. Emphasis: In order to forward a datagram, the sending device must first know what routers are connected to the local network and which route processor maintains the shortest path to the destination devise. A default gateway is used to forward all non-local packets. Discuss the commands to configure a default gateway on both the IOS and Set command-based systems. You can add several routes to the switch, including the default route. This does not make the switch a router, nor does this command effect the switching of IP packets through the switch. This command is solely for IP communications to the switch, not for data through the switch. Transition: The following describes how to remove an interface from a null domain.
- #76 &lt;number&gt; Purpose: This slide discusses the ping command. Emphasize: Use the ping command to test connectivity to remote hosts. The ping command will return one of the following responses: Success rate is 100 percent or ip address is alive. This response occurs in 1 to 10 seconds, depending on network traffic and the number of ICMP packets sent. Destination does not respond. No answer message is returned if the host does not Unknown host. This response occurs if the targeted host does not exit Destination unreachable. This response occurs if the default gateway cannot reach the specified network Network or host unreachable. This response occurs if there is no entry in the route table for the host or network. You can also test the routes packets will take from the route processor to a specific destination by using the trace ip destination command. For more information on the trace ip command, refer to the Cisco IOS Release 12.0 Command Summary . Transition: Following is the visual for the laboratory exercise.
- #77 &lt;number&gt; Purpose: This page summarize what was discussed in this module Transition: The following are the review questions.