1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 3 v3.0 Module 5 Switches

222 © 2003, Cisco Systems, Inc. All rights reserved. Objectives LAN design LAN switches

333 © 2003, Cisco Systems, Inc. All rights reserved. LAN Design Goals Functionality Scalability Adaptability Manageability

444 © 2003, Cisco Systems, Inc. All rights reserved. LAN Design Considerations To maximize available LAN bandwidth and performance, the design considerations are: The function and placement of servers Collision-detection issues Segmentation issues Broadcast domain issues

555 © 2003, Cisco Systems, Inc. All rights reserved. LAN Design Methodology Gather requirements and expectations Analyze requirements and data Design the Layer 1, 2, and 3 LAN structure, or topology Document the logical and physical network implementation

666 © 2003, Cisco Systems, Inc. All rights reserved. Layer 1 Design

777 © 2003, Cisco Systems, Inc. All rights reserved. Typical MDF in Star Topology

888 © 2003, Cisco Systems, Inc. All rights reserved. Extended Star Topology in a Multi-Building Campus

999 © 2003, Cisco Systems, Inc. All rights reserved. Layer 1 Documentation Logical Diagram

10 © 2003, Cisco Systems, Inc. All rights reserved. Cut Sheet

11 © 2003, Cisco Systems, Inc. All rights reserved. Layer 2 Design: Developing a LAN Topology Switch frames based on MAC address information Provide error detection Reduce congestion in network

12 © 2003, Cisco Systems, Inc. All rights reserved. Microsegmentation of the Network Microsegmentation of the network reduces the size of collision domains and reduces collisions.

13 © 2003, Cisco Systems, Inc. All rights reserved. Asymmetric Switching Asymmetric switching provides switched connections between ports of unlike bandwidth, such as a combination of 10-Mbps and 100- Mbps ports

14 © 2003, Cisco Systems, Inc. All rights reserved. Layer 2 Switch Collision Domains

15 © 2003, Cisco Systems, Inc. All rights reserved. Layer 3 Design

16 © 2003, Cisco Systems, Inc. All rights reserved. Use Routers to Impose Logical Structure Routers provide scalability because they serve as firewalls for broadcasts. They can also provide scalability by dividing networks into subnetworks, or subnets, based on Layer 3 addresses.

17 © 2003, Cisco Systems, Inc. All rights reserved. Physical Network Maps

18 © 2003, Cisco Systems, Inc. All rights reserved. Setting Up VLAN Implementation

19 © 2003, Cisco Systems, Inc. All rights reserved. VLAN Communication

20 © 2003, Cisco Systems, Inc. All rights reserved. Access Layer The access layer provides users in workgroups access to the network. It is the entry point for user workstations and servers to the network.

21 © 2003, Cisco Systems, Inc. All rights reserved. Access Layer Functions of the Access Layer: Shared Bandwidth, if hub is used. Switched Bandwidth, if switch is used. MAC Layer filtering. Microsegmentation: creates small collision domain.

22 © 2003, Cisco Systems, Inc. All rights reserved. Access Layer Switches Catalyst 1900 series Catalyst 2820 series Catalyst 2950 series Catalyst 4000 series Catalyst 5000 series

23 © 2003, Cisco Systems, Inc. All rights reserved. Distribution Layer The distribution layer of the network is between the access and core layers. It helps to define and separate the core. The purpose of this layer is to provide a boundary definition in which packet manipulation can take place.

24 © 2003, Cisco Systems, Inc. All rights reserved. Distribution Layer In a switched network, the distribution layer includes several functions such as the following: Aggregation of the wiring-closet connections Broadcast/multicast domain definition VLAN routing Any media transitions that need to occur Security

25 © 2003, Cisco Systems, Inc. All rights reserved. Distribution Layer Switches Cisco Catalyst 2926G Cisco Catalyst 6000 Family Cisco Catalyst 5000 Family

26 © 2003, Cisco Systems, Inc. All rights reserved. Core Layer The core layer is a high-speed switching backbone. The core layer should be designed to switch packets as fast as possible.

27 © 2003, Cisco Systems, Inc. All rights reserved. Core Layer Switches Catalyst 6500 series IGX 8400 series Catalyst 8500 series Lightstream 1010