1. © 2003, Cisco Systems, Inc. All rights reserved. 2-1 Introducing Campus Networks Building Cisco Multilayer Switched Networks (BCMSN) v3.0

2. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-2 Learner Skills and Knowledge Cisco CCNA ® certification NOTE: Practical experience with deploying and operating networks based on Cisco network devices and Cisco IOS software is strongly recommended.

3. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-3 In this course, learners will find out how to create an efficient and expandable enterprise network by installing, configuring, monitoring, and troubleshooting network infrastructure equipment according to the Campus Infrastructure module in the Enterprise Composite Network Model. Building Cisco Multilayer Switched Networks Course Goal

4. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-4 Course Flow Network Requirements Course Introduction Lunch AMAM PMPM Day 1Day 2Day 3Day 4Day 5 Defining VLANs Implementing Spanning Tree Implementing Inter-VLAN Routing Implementing High Availability WLANs Minimizing Service Loss and Data Theft in a Campus Network Configuring Campus Switches to Support Voice Implementing Inter-VLAN Routing Minimizing Service Loss Implementing Spanning Tree Implementing High Availability

5. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-5 Cisco Icons and Symbols End Users Ethernet Network Cloud Router PC Laptop File Server Wireless Router Voice- Enabled Router Multilayer Switch Workgroup Switch Workgroup Switch: Voice-Enabled 100BASE-T Hub Bridge Lightweight Single-Radio Access Point Access Point IP Phone Autonomous Dual-Band Access Point Lightweight Dual-Band Access Point Wireless LAN Controller Wireless Link

6. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-6 Cisco Career Certifications

7. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-7 Cisco Career Certifications Expand Your Professional Options and Advance Your Career Cisco Certified Network Professional (CCNP) Professional CCIE CCNP CCNA Associate http://www.cisco.com/go/certifications Recommended Training Through Cisco Learning Partners Required Exam 642-901 BSCI 642-812 BCMSN 642-825 ISCW Building Scalable Cisco Internetworks Building Cisco Multilayer Switched Networks Implementing Secure Converged Wide Area Networks Optimizing Converged Cisco Networks 642-845 ONT Expert

8. © 2003, Cisco Systems, Inc. All rights reserved. 2-8 Introducing Campus Networks

9. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-9 Intelligent Information Network Intelligent Information Network (IIN) integrates networked resources and information assets. IIN extends intelligence across multiple products and infrastructure layers. IIN actively participates in the delivery of services and applications. Three phases in building an IIN are: –Integrated transport –Integrated services –Integrated applications

10. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-10 Cisco SONA Framework The Cisco Service-Oriented Network Architecture (SONA) is an architectural framework. SONA brings several advantages to enterprises: –Outlines how enterprises can evolve toward the IIN –Illustrates how to build integrated systems across a fully converged intelligent network –Improves flexibility and increases efficiency

11. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-11 Cisco SONA Framework Layers

12. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-12 Cisco Enterprise Architecture

13. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-13 Nonhierarchical Network Devices Large collision domain Large broadcast domain High latency Difficult to troubleshoot

14. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-14 Issues No traffic between VLANs Unbounded broadcast domain Servers not centrally located Layer 2 Switching Hardware-based bridging Wire-speed performance Collision domain per port Traffic containment based on MAC address

15. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-15 Layer 3 Routing Single broadcast domain per interface ACLs can be applied between segments Issues High per-port cost Layer 3 processing required High latency over Layer 2 switching

16. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-16 Multilayer Switching Combined functionality –Layer 2 switching –Layer 3 switching –Layer 4 switching Low latency High-speed scalability

17. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-17 Issues with Multilayer Switches in a Nonhierarchical Network Single point of failure for Layer 2 and Layer 3 Underutilization of hardware Spanning tree complexity Servers not centrally located

18. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-18 Hierarchical Campus Model

19. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-19 ECNM Functional Areas

20. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-20 Enterprise Composite Network Model

21. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-21 Modules in the Enterprise Campus

22. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-22 Campus Infrastructure Module

23. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-23 Switch Configuration Interfaces Two interfaces are used to configure Cisco Catalyst switches: –Cisco Catalyst software –Cisco IOS Cisco Catalyst software was traditionally used to configure Layer 2 parameters on the modular switches: – Cisco Catalyst 4000, 5500, 6500 Series – These switches now support Cisco IOS (native IOS) Cisco IOS software is standard for most other switches and for Layer 3 configuration on the modular switches.

24. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-24 Cisco Catalyst Software Cisco Catalyst software is used to configure Layer 2 parameters. Cisco Catalyst software configuration commands are prefaced with the keyword set. –Console(enable) set port enable 3/5 Layer 3 configuration is implemented on MSFC with the Cisco IOS interface. Some platforms can now use the Cisco IOS interface to configure both Layer 2 and Layer 3 (native IOS). Cisco Catalyst 4000, 5500, and 6500 switches

25. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-25 Cisco IOS Interface On most Catalyst switches, Cisco IOS interface is standard for Layer 2 configuration Layer 3 configuration on multilayer switch

26. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-26 Summary The SONA framework guides the evolution of the enterprise network toward IIN. Cisco enterprise architecture with a hierarchical network model facilitates the deployment of converged networks. Nonhierarchical network designs do not scale and do not provide the required security necessary in a modern topology. Layer 2 networks do not provide adequate security or hierarchical networking. Router-based networks provide greater security and hierarchical networking; however, they can introduce latency issues.

27. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-27 Summary (Cont.) Multilayer switches combine both Layer 2 and Layer 3 functionality to support the modern campus network topology. Multilayer switches can be used in nonhierarchical networks; however, they will not perform at the optimal level. The enterprise composite model identifies the key components and logical design for a modern topology. Implementation of an ECNM provides a secure, robust network with high availability. The Campus infrastructure, as part of an ECNM, provides additional security and high availability at all levels of the campus. The two Cisco Catalyst switch interfaces have different features and different font.

28. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-28 © 2002, Cisco Systems, Inc. All rights reserved. 28 Basic Layer 2 Switching and Bridging Functions

29. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-29 Objectives Upon completing this lesson, you will be able to: Describe Layer 2 switching and bridging operations and modes Describe how LAN switches use and populate the MAC address table

30. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-30 Bridges Bridge Categories Local Bridge –An internetworking device designed to interconnect two bridges within close proximity of one another –Also support network separation To reduce network utilization by splitting a LAN into more than one independent LAN Remote Bridge –Converts LAN traffic into a wide area protocol thus allowing a LAN to be connected to a WAN

31. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-31 Types of Bridges Transparent Bridge Remote bridge with identical data link protocol Can support different physical media Translating Bridge Connection with different data link protocol –Frame conversion For example, Ethernet to Token ring or Token ring to Ethernet May require assembly and reassembly –Transmission rate conversion

32. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-32 Bridging and Switching Bridges forward traffic based on MAC level address A bridge may perform protocol conversion or speed matching between different LAN types Bridges provides buffering of packets A switch is a bridge with all ports use the same frame type; also called a LAN switch to distinguish from an ATM or telecommunications switch

33. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-33 Why Bridging and Switching? Decrease traffic on LAN segments Extend LAN without increasing congestion Bridge different network protocols Speed matching Security Reliability: fault isolation and bandwidth balancing

34. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-34 Traffic and LAN Size Joining LAN segments with a hub or repeater increases traffic. All machines share the same media (same collision domain). A: total traffic 6 MbpsB: total traffic 5 Mbps A+B: total traffic 11 Mbps repeater

35. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-35 Switched LAN Segments A switch only forwards packets when necessary. learns network addresses of machines connected to each port doesn’t forward traffic between machines on same port provides packet buffering and retiming, reducing collisions does forward all broadcast traffic may forward multicast traffic, depending on switch A sw/ B: traffic 7 MbpsswitchB sw/ A: traffic 6 Mbps

36. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-36 LAN Extension a switch can extend length limit of network, since it provides packet retiming and retransmission bridge: different media and protocol to extend length limit switches are not subject to repeater count limit on ethernet Fast Ethernet switch Fast Ethernet 300 m wireless bridge up to 40 km

37. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-37 Bridging Different Protocols a bridge can convert frame formats requires compatible network addresses, e.g. ethernet & token ring are OK, but not ethernet and ATM frame conversion may lose some information about the frame Ethernet bridge Token Ring

38. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-38 Protocol Conversion Problems Ethernet does not have frame “address seen” or “copied” bits (set by receiver in Token Ring Frame Status byte) Ethernet does not have priorities or access control flags Token Ring frame may be too long for ethernet Maximum throughput of ethernet and token ring not the same: some frames may be dropped Token Ring doesn’t have a length field: bridge must buffer and compute Data 0 - 18180 Frame control Destination address 1 Start delimiter 1 byte Access control Source address End delimiter Frame status Frame CRC 66411 1 Data 46 - 1500 SOH Destination address Source address Frame CRC 664 1 byte length 2 Ethernet Frame Token Ring Frame

39. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-39 Speed Matching A switch can connect segments operating at different speeds How to handle overload of a slow or busy segment? back pressure (false collisions) drop frames Ethernet switches can support 10, 100 Mbps, and gigabit Bridging ethernets is simple: packet formats are the same Fast Ethernet hub switch 10 Mbps Ethernet hub Fast Ethernet server Gigabit Ethernet server 10 Mbps ethernet 100 Mbps ethernet

40. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-40 Security A hub forwards all packets to all ports. Any host can listen to packets to/from another host, using programs like tcpdump, etherwatch, or snoop. Hub: shared media access Switch: selective access A switch only forwards packets to port containing the destination host. Computers on other ports cannot eavesdrop. rats! ooooh..

41. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-41 Address learning Forward/filter decision Loop avoidance Ethernet Switches and Bridges

42. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-42 Cut-Through Switch checks destination address and immediately begins forwarding frame. Fragment-Free Switch checks the first 64 bytes, then immediately begins forwarding frame. Store and Forward Complete frame is received and checked before forwarding. Transmitting Frames

43. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-43 MAC Address Table Initial MAC address table is empty.

44. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-44 Learning Addresses Station A sends a frame to station C. Switch caches the MAC address of station A to port E0 by learning the source address of data frames. The frame from station A to station C is flooded out to all ports except port E0 (unknown unicasts are flooded).

45. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-45 Learning Addresses (Cont.) Station D sends a frame to station C. Switch caches the MAC address of station D to port E3 by learning the source address of data frames. The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded).

46. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-46 Filtering Frames Station A sends a frame to station C. Destination is known; frame is not flooded.

47. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-47 Filtering Frames (Cont.) Station A sends a frame to station B. The switch has the address for station B in the MAC address table.

48. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-48 Station D sends a broadcast or multicast frame. Broadcast and multicast frames are flooded to all ports other than the originating port. Broadcast and Multicast Frames

49. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-49 Summary Ethernet switches and bridges increase the available bandwidth of a network by creating dedicated network segments and interconnecting the segments. Switches and bridges use one of three operating modes to transmit frames: store and forward, cut-through, and fragment-free. Switches and bridges maintain a MAC address table to store address-to-port mappings so it can determine the locations of connected devices. When a frame arrives with a known destination address, it is forwarded only on the specific port connected to the destination station.

50. © 2003, Cisco Systems, Inc. All rights reserved. 2-50 VLANs and VTP

51. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-51 Objectives Upon completing this module, you will be able to: Configure, verify, and troubleshoot VLANs on a switched network Configure, verify, and troubleshoot VLAN trunks in a switched network Configure, verify, and troubleshoot VTP in a switched network

52. © 2003, Cisco Systems, Inc. All rights reserved. 2-52 Implementing VLANs © 2003, Cisco Systems, Inc. All rights reserved. BCMSN 2.0—2-52

53. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-53 Traditional Campus Networks Collision Domain 1 Collision Domain 2 Broadcast Domain Bridges terminate collision domains

54. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-54 Performance Issues Multicast, broadcast, and unknown destination events become global events Server A ARP I need to know the MAC address for Server A ARP

55. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-55 Broadcast Issues Broadcasts can consume all available bandwidth Each device must decode the broadcast frame Server A

56. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-56 Solution: Localizing Traffic 10.1.1.010.1.2.0 10.1.3.0 LAN broadcasts terminate at the router interface

57. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-57 Solution: Localizing Traffic (Cont.) VLAN3 VLAN2VLAN1 VLANs contain broadcast traffic and separate traffic flows

58. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-58 VLAN7 VLAN6 VLAN5 Current Campus Networks VLAN3 VLAN2 VLAN1 VLAN10 VLAN9 VLAN8 Layer 3 devices interconnect LAN segments while still containing broadcast domains

59. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-59 A VLAN = A Broadcast Domain = Logical Network (Subnet) VLAN Overview Layer 2 connectivity Logical organizational flexibility Single broadcast domain Management Basic security

60. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-60 VLAN Operations Switch A Green VLAN Black VLAN Red VLAN Switch B Green VLAN Black VLAN Red VLAN Each logical VLAN is like a separate physical bridge VLANs can span across multiple switches

61. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-61 VLAN Operations Switch A Green VLAN Black VLAN Red VLAN Switch B Green VLAN Black VLAN Red VLAN Trunk Each logical VLAN is like a separate physical bridge VLANs can span across multiple switches Trunks carries traffic for multiple VLANs Fast Ethernet

62. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-62 VLANs plus routing limits broadcasts to the domain of origin. VLANs Establish Broadcast Domains

63. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-63 Layer 2 End-to-End VLANs Distribution Layer Core Layer Fast or Gigabit Ethernet Wiring Closet Fast Ethernet Workgroup Servers Switched Ethernet Enterprise Servers Inter-VLAN Routing End-to-end VLANs span the switch fabric

64. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-64 Local VLANs generally reside in the wiring closet. Local VLANs

65. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-65 Benefits of Local VLANs in the ECNM Deterministic traffic flow Active redundant paths High availability Finite failure domain Scalable design

66. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-66 All users attached to same switch port must be in the same VLAN. Static VLANs

67. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-67 Issues in a Poorly Designed Network Unbounded failure domains Large broadcast domains Large amount of unknown MAC unicast traffic Unbounded multicast traffic Management and support challenges Possible security vulnerabilities

68. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-68 Scalable Network Addressing Allocate IP address spaces in contiguous blocks. Allocate one IP subnet per VLAN. IT, Human Resources Sales, MarketingFinance, Accounting

69. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-69 Interconnection Technologies TechnologyUse Fast EthernetConnects end-user devices to the access layer switch Gigabit Ethernet Access to distribution switch, high-use servers 10-Gigabit Ethernet High-speed switch to switch links, backbones EtherChannelHigh-speed switch to switch links, backbones with redundancy

70. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-70 Determining Equipment and Cabling Needs Each link provides adequate bandwidth for traffic aggregating over that link.

71. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-71 VLANs and the Logical Network

72. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-72 Network Traffic Types Traffic types to consider: Network management IP telephony Multicast Normal data Scavenger class

73. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-73 Traffic Path for IP Telephony Consider complete traffic path when placing equipment and configuring VLANs.

74. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-74 Traffic Path for IP Multicast Consider complete traffic path when placing equipment and configuring VLANs.

75. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-75 Configuring VLANs in Global Mode Switch#configure terminal Switch(config)#vlan 3 Switch(config-vlan)#name Vlan3 Switch(config-vlan)#exit Switch(config)#end

76. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-76 Configuring VLANs in VLAN Database Mode Switch#vlan database Switch(vlan)#vlan 3 VLAN 3 added: Name: VLAN0003 Switch(vlan)#exit APPLY completed. Exiting....

77. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-77 Deleting VLANs in Global Mode Switch#configure terminal Switch(config)#no vlan 3 Switch(config)#end

78. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-78 Deleting VLANs in VLAN Database Mode Switch#vlan database Switch(vlan)#no vlan 3 VLAN 3 deleted: Name: VLAN0003 Switch(vlan)#exit APPLY completed. Exiting....

79. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-79 VLAN Membership Modes VLAN membership can either be static or dynamic.

80. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-80 Assigning Access Ports to a VLAN Switch(config)#interface gigabitethernet 1/1 Enters interface configuration mode Switch(config-if)#switchport mode access Configures the interface as an access port Switch(config-if)#switchport access vlan 3 Assigns the access port to a VLAN

81. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-81 Verifying the VLAN Configuration Switch#show vlan [id | name] [vlan_num | vlan_name] VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/5, Fa0/7 Fa0/8, Fa0/9, Fa0/11, Fa0/12 Gi0/1, Gi0/2 2 VLAN0002 active 51 VLAN0051 active 52 VLAN0052 active … VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 1002 1003 2 enet 100002 1500 - - - - - 0 0 51 enet 100051 1500 - - - - - 0 0 52 enet 100052 1500 - - - - - 0 0 … Remote SPAN VLANs ------------------------------------------------------------------------------ Primary Secondary Type Ports ------- --------- ----------------- ------------------------------------------

82. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-82 Verifying the VLAN Port Configuration Switch#show running-config interface {fastethernet | gigabitethernet} slot/port Displays the running configuration of the interface Switch#show interfaces [{fastethernet | gigabitethernet} slot/port] switchport Displays the switch port configuration of the interface Switch#show mac-address-table interface interface-id [vlan vlan-id] [ | {begin | exclude | include} expression] Displays the MAC address table information for the specified interface in the specified VLAN

83. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-83 Troubleshooting VLANs

84. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v2.0—2-84 Summary A VLAN is a logical grouping of switch ports connecting nodes of virtually any type with no regard to physical location. An end-to-end VLAN spans the entire switched network, while a local VLAN is restricted to a single switch. Static VLANs involve switch ports that you manually assign to a particular VLAN. You can configure VLANs using Cisco IOS commands in VLAN configuration mode. Once a VLAN has been defined, you can assign switch ports to it. You use show commands to confirm that a VLAN and its associated ports have been configured correctly. To troubleshoot VLANs, you should check the physical connections, switch configuration, and VLAN configuration.