ccna exp3 - chapter01 - lan design

8/3/2019 CCNA Exp3 - Chapter01 - Lan Design

http://slidepdf.com/reader/full/ccna-exp3-chapter01-lan-design 1/56

Chapter 1: LAN Design

CCNA Ex loration 4.0

Please purchase apersonal license.



Overview

Hc vin mng Bach Khoa - Website: www.bkacad.com 2



Hierarchical Network Model




Switched LANs, access layer overview


• The hierarchical design model includes the following 3 layers:1. The access layer provides users in workgroups access to the

network.

2. The distribution layer provides policy-based connectivity.3. The core layer provides optimal transport between sites.

• The core layer is often referred to as the backbone.• By separating the various functions that exist on a network, the

network design becomes modular, which facilitates scalability and

performance



Access Layer


• The main purpose of the access layer is to provide a means ofconnecting devices to the network and controlling which devices areallowed to communicate on the network.



Access layer switches

• Access layer switches operate at Layer 2 of the OSI model and provideservices such as VLAN membership.

• Access layer functions also include MAC layer filtering and microsegmentation.

– MAC layer filtering allows switches to direct frames only to the switch portthat is connected to the destination device.

– The switch creates small Layer 2 segments called microsegments. Thecollision domain can be as small as two devices

• An access layer switch should provide this functionality with low cost and high


por ens y.

– Catalyst 1900 series







Distribution Layer


• The distribution layer controls the flow of network traffic using policies anddelineates broadcast domains by performing routing functions between virtualLANs (VLANs) defined at the access layer. – VLANs allow you to segment the traffic on a switch into separate

subnetworks.



Extra:Distribution Layer

• The ur ose of this la er is to rovide a boundar definition in which acket


manipulation can take place.• Networks are segmented into broadcast domains by this layer.

• Policies can be applied and access control lists can filter packets.

• The distribution layer also prevents problems from affecting the core layer.

• Switches in this layer operate at Layer 2 and Layer 3.

• The distribution layer includes several functions such as the following: – Aggregation of the wiring closet connections

– Broadcast/multicast domain definition

– Virtual LAN (VLAN) routing

– Any media transitions that need to occur – Security



Distribution layer switches

•

2926G6500


switches.• The switch must be able to accommodate the total amount of traffic from the

access layer devices.

• The distribution layer combines VLAN traffic and is a focal point for policydecisions about traffic flow.

• For these reasons distribution layer switches operate at both Layer 2 andLayer 3.

• The following Cisco switches are suitable for the distribution layer:

– Catalyst 2926G

– Catalyst 5000 family

– Catalyst 6000 family



Extra:Core Layer


• The core layer is a high-speed switching backbone.

• If they do not have an associated router module, an external router isused for the Layer 3 function.

• This layer of the network design should not perform any packet

manipulation.• Packet manipulation, such as access list filtering, would slow down the

switching of packets.

• Providing a core infrastructure with redundant alternate paths givesstability to the network in the event of a single device failure.



A Hierarchical Network in a Medium-Sized Business




Benefits of a Hierarchical Network




Hierarchical Network DesignPrinciples




Network Diameter




Bandwidth Aggregation




Extra: EtherChannel




Redundancy




Extra: High Availability




What is a Converged Network ?

Small and medium-sized businesses are embracing theidea of running voice and video services on their data


.

(VoIP) affect a hierarchical network.



Advanced Technology


• One benefit of a converged network is that there is just one network tomanage.

• Another benefit is lower implementation and management costs.



New Options


• You can accomplish the same function using special softwareintegrated with a personal computer. Softphones, such as the Cisco IPCommunicator, offer a lot of flexibility for businesses.



Extra: Cisco IP Communicator


• Cisco IP Communicator—a software-based application that deliversenhanced telephony support through the PC —is designed to meetdiverse customer needs by serving as a supplemental telephone when

traveling, a telecommuting device, or as a primary desktop telephone.• With Cisco IP Communicator, remote users don't just take their office

extension with them; they also enjoy access to the same familiar phoneservices that they have in the office.



Separate Voice, Video and Data Networks






• Using a properly designed hierarchical network, and implementing QoSpolicies that prioritize the audio data, voice data can be converged ontoan existing data network with little to no impact on audio, video quality.



Traffic Flow Analysis


• http://www.cisco.com/warp/public/732/Tech/nmp/netflow/partners/freeware/index.shtml



User Communities Analysis

User communityanalysis is the processof identifying various

groupings of users and

their impact on networkperformance




User Communities Analysis




Data Stores and Data Servers Analysis




Topology Diagrams




Extra: Server Placement


• An enterprise server supports all the users on the network by offeringservices, such as e-mail or Domain Name System (DNS) that everyone in anorganization would need because it is a centralized function.

• A workgroup server supports a specific set of users, offering services such asword processing and file sharing.

• Enterprise servers should be placed in the main distribution facility (MDF).• Workgroup servers should be placed in the intermediate distribution

facilities (IDFs) closest to the users accessing the applications on theseservers.



S it h F F t



Switch Form Factors


Port Density



Port Density


Forwarding Rates



Forwarding Rates


Link Aggregation



Link Aggregation


Power over Ethernet



Power over Ethernet


Power over Ethernet (PoE)allows the switch to deliver

power to a device over theexisting Ethernet cabling

Layer 3 Functions



Layer 3 Functions


Access Layer Switch Features



Access Layer Switch Features


Distribution Layer Switch Features



Distribution Layer Switch Features


Core Layer Switch Features



Core Layer Switch Features


Switches for SMB



Switches for SMB


• Activity 1.2.4.1

Test your knowledge



Test your knowledge


Activity 1.2.4.2

Test your knowledge



Test your knowledge


Summary



Summary


ccna exp3 - chapter01 - lan design

Documents