Building Cisco Multilayer Switched Networks BCMSN Introducingv 3

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. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -2

Course Goal 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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -3

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

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

Cisco Career Certifications © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2.

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

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

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -9

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -10

Cisco SONA Framework Layers © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v

Cisco Enterprise Architecture © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2.

Nonhierarchical Network Devices • Large collision domain • Large broadcast domain • High latency

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

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -15

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

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -17

Hierarchical Campus Model © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2.

ECNM Functional Areas © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2.

Enterprise Composite Network Model © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v

Modules in the Enterprise Campus © 2003, Cisco Systems, Inc. All rights reserved. BCMSN

Campus Infrastructure Module © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2.

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. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -23

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). © 2003, Cisco Systems, Inc. All rights reserved. Cisco Catalyst 4000, 5500, and 6500 switches BCMSN v 2. 0— 2 -24

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

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. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -26

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. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -27

Basic Layer 2 Switching and Bridging Functions ©© 2002, 2003, Cisco. Systems, Inc. Allrightsreserved.

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -29

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -30

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -31

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -32

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -33

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

Switched LAN Segments A sw/ B: traffic 7 Mbps switch B sw/ A: traffic 6 Mbps • 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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -35

LAN Extension wireless bridge up to 40 km switch Fast Ethernet 300 m • 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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -36

Bridging Different Protocols Ethernet bridge Token Ring • 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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -37

Protocol Conversion Problems Ethernet Frame 1 byte SOH 6 Destination address 6 2 Source address length 46 - 1500 Data 4 Frame CRC Token Ring Frame 1 byte Start delimiter 1 1 Access control Frame control 6 Destination address 6 Source address 0 - 18180 Data 4 1 1 Frame CRC End delimiter Frame status 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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -38

Speed Matching Fast Ethernet hub switch Gigabit Ethernet 10 Mbps Ethernet hub Fast Ethernet 10 Mbps ethernet 100 Mbps ethernet server 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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -39

Security Hub: shared media access ooooh. . 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. © 2003, Cisco Systems, Inc. All rights reserved. Switch: selective access rats! A switch only forwards packets to port containing the destination host. Computers on other ports cannot eavesdrop. BCMSN v 2. 0— 2 -40

Ethernet Switches and Bridges • Address learning • Forward/filter decision • Loop avoidance ©

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

MAC Address Table • Initial MAC address table is empty. © 2003, Cisco Systems,

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

Learning Addresses (Cont. ) • Station D sends a frame to station C. • Switch caches the MAC address of station D to port E 3 by learning the source address of data frames. • The frame from station D to station C is flooded out to all ports except port E 3 (unknown unicasts are flooded). © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -45

Filtering Frames • Station A sends a frame to station C. • Destination is

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

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

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. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -49

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

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -51

Implementing VLANs ©© 2003, Cisco. Systems, Inc. Allrightsreserved. BCMSN 2. 0— 2 -52

Traditional Campus Networks Broadcast Domain Collision Domain 1 Collision Domain 2 • Bridges terminate

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

Broadcast Issues Server A • Broadcasts can consume all available bandwidth • Each device

Solution: Localizing Traffic 10. 1. 1. 0 10. 1. 2. 0 10. 1. 3.

Solution: Localizing Traffic (Cont. ) VLAN 1 VLAN 2 VLAN 3 • VLANs contain

Current Campus Networks VLAN 1 VLAN 2 VLAN 3 VLAN 5 VLAN 6 VLAN 7 VLAN 8 VLAN 9 VLAN 10 • Layer 3 devices interconnect LAN segments while still containing broadcast domains © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -58

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

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

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

VLANs Establish Broadcast Domains • VLANs plus routing limits broadcasts to the domain of

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

Local VLANs • Local VLANs generally reside in the wiring closet. © 2003, Cisco

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

Static VLANs • All users attached to same switch port must be in the

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -67

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

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

Determining Equipment and Cabling Needs Each link provides adequate bandwidth for traffic aggregating over

VLANs and the Logical Network © 2003, Cisco Systems, Inc. All rights reserved. BCMSN

Network Traffic Types Traffic types to consider: • Network management • IP telephony •

Traffic Path for IP Telephony Consider complete traffic path when placing equipment and configuring

Traffic Path for IP Multicast Consider complete traffic path when placing equipment and configuring

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

Configuring VLANs in VLAN Database Mode Switch#vlan database Switch(vlan)#vlan 3 VLAN 3 added: Name: VLAN 0003 Switch(vlan)#exit APPLY completed. Exiting. . © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -76

Deleting VLANs in Global Mode Switch#configure terminal Switch(config)#no vlan 3 Switch(config)#end © 2003, Cisco

Deleting VLANs in VLAN Database Mode Switch#vlan database Switch(vlan)#no vlan 3 VLAN 3 deleted: Name: VLAN 0003 Switch(vlan)#exit APPLY completed. Exiting. . © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -78

VLAN Membership Modes • VLAN membership can either be static or dynamic. © 2003,

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 © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -80

Verifying the VLAN Configuration Switch#show vlan [id | name] [vlan_num | vlan_name] VLAN Name Status Ports --------------------1 default active Fa 0/1, Fa 0/2, Fa 0/5, Fa 0/7 Fa 0/8, Fa 0/9, Fa 0/11, Fa 0/12 Gi 0/1, Gi 0/2 2 VLAN 0002 active 51 VLAN 0051 active 52 VLAN 0052 active … VLAN ---1 2 51 52 … Type ----enet SAID -----100001 100002 100051 100052 MTU ----1500 Parent ------ Ring. No ------ Bridge. No ---- Stp ---- Brdg. Mode ---- Trans 1 -----1002 0 0 0 Trans 2 -----1003 0 0 0 Remote SPAN VLANs ---------------------------------------Primary Secondary Type Ports ---------------------BCMSN v 2. 0— 2 -81 © 2003, Cisco Systems, Inc. All rights reserved.

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-id [vlan-id] [ | {begin | exclude | include} expression] • Displays the MAC address table information for the specified interface in the specified VLAN © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -82

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

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. © 2003, Cisco Systems, Inc. All rights reserved. BCMSN v 2. 0— 2 -84