CCNP BSCI Quick Reference Sheets IP Multicast · PDF fileCCNP BSCI Quick Reference Sheets Exam...

CCNP BSCIQuick Reference SheetsExam 642-901
The Evolving Network Model
EIGRP
OSPF
IS-IS
Optimizing Routing
BGP
IP Multicast
IPv6 Introduction
Brent StewartDenise Donohue
ciscopress.com

ABOUT THE AUTHORS
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2007 Cisco Systems Inc. All rights reserved. This publication is protected by copyright. Please see page 73 for more details.
CCNP BSCI Quick Reference Sheets
About the AuthorsBrent Stewart, CCNP, CCDP, MCSE, Certified Cisco Systems Instructor, is a network administratorfor CommScope. He participated in the development of BSCI, and has seperately developed trainingmaterial for ICND, BSCI, BCMSN, BCRAN, and CIT. Brent lives in Hickory, NC, with his wife,Karen and children, Benjamin, Kaitlyn, Madelyn, and William.
Denise Donohue, CCIE No. 9566, is a Design Engineer with AT&T. She is responsible for designingand implementing data and VoIP networks for SBC and AT&T customers. Prior to that, she was aCisco instructor and course director for Global Knowledge. Her CCIE is in Routing and Switching.

ICONS USED IN THIS BOOK
Icons Used in This Book
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Si
WebBrowser
Internal Firewall IDS Database
Router 7507Router
Multilayer Switchwith Text
MultilayerSwitch
SwitchCommunication Server
IDC
App Server

CHAPTER 1
The Evolving NetworkModel
The Hierarchical Design ModelCisco used the three-level Hierarchical Design Model for years. Thisolder model provided a high-level idea of how a reliable network mightbe conceived, but it was largely conceptual because it didnt providespecific guidance. Figure 1-1 shows the Hierarchical Design Model.
FIGURE 1-1 Hierarchical Design Model
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This same three-layer hierarchy can be used in the WAN with a centralheadquarters, division headquarters, and units.
FIGURE 1-2 Three-Layer Network Design
Core
Access
Distribution
Si
Si Si Si Si
Figure 1-2 is a simple drawing of how the three-layer model mighthave been built out. A distribution layer-3 switch is used for each build-ing on campus, tying together the access switches on the floors. Thecore switches link the various buildings together.
Core
Access
Distribution
The layers break a network in the following way:
n Access layerEnd stations attach to the network using low-costdevices.
n Distribution layerIntermediate devices apply policies.
Route summarization
Policies applied, such as:
Route selection
Access lists
Quality of Service (QoS)
Double-click to view image at full size in an external viewer.

CHAPTER 1
THE EVOLVING NETWORK MODEL
n Core layerThe backbone that provides a high-speed pathbetween distribution elements.
Distribution devices are interconnected.
High speed (there is a lot of traffic).
No policies (it is tough enough to keep up).
Later versions of this model include redundant distribution, coredevices, and connections, which make the model more fault-tolerant.
Problems with the Hierarchical Design ModelThis early model was a good starting point, but it failed to address keyissues, such as:
n Where do wireless devices fit in?
n How should Internet access and security be provisioned?
n How do you account for remote access, such as dial-up or VPN?
n Where should workgroup and enterprise services be located?
Enterprise Composite NetworkModelThe newer Cisco modelthe Enterprise Composite Modelis significantlymore complex and attempts to address the shortcomings of the HierarchicalDesign Model by expanding the older version and making specific
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recommendations about how and where certain network functions shouldbe implemented. This model is based on the principles described in theCisco Architecture for Voice, Video, and Integrated Data (AVVID).
The Enterprise Composite Model (see Figure 1-3) is broken into threelarge sections:
n Enterprise CampusSwitches that make up a LAN
n Enterprise EdgeThe portion of the enterprise network connectedto the larger world.
n Service Provider EdgeThe different public networks that areattached
The first section, the Enterprise Campus, looks like the old HierarchicalDesign Model with added details. It features six sections:
n Campus BackboneThe core of the LAN
n Building DistributionLinks subnets/VLANs and applies policy
n Building AccessConnects users to network
n Management
n Edge DistributionA distribution layer out to the WAN
n Server FarmFor Enterprise services

CORE
BUILDING B
Campus Backbone A Campus Backbone B
BUILDING CBUILDING A
BuildingDistribution A
BuildingDistribution B
BuildingDistribution A
BuildingDistribution B Building
Distribution ABuilding
Distribution B
2nd Floor Access4th Floor Access
1st Floor Access 3rd Floor Access 1st Floor Access 3rd Floor Access 1st Floor Access 3rd Floor Access
CHAPTER 1
FIGURE 1-3 The Enterprise Composite Model
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The Enterprise Edge, shown in Figure 1-4, details the connections fromthe campus to the WAN and includes:
n E-commerce
n Internet connectivity
n Remote access
n WAN

Remote Access
WAN
Campus BackboneEdge
Distribution
Internal Router
DMZ Firewall
Web
DatabaseIDC
App Server
Internet Router
Corporate Router
Dial-In
Internal RouterDMZ Firewall
PublicServers
Internet Router
Internal Router VPN
IDS
PPP
Service Provider EdgeEnterprise Edge
Internet
PSTN
Frame Relay ATM
Internal Firewall
Internal Firewall
Caching
Firewall
E-Commerce
Internet
CHAPTER 1
FIGURE 1-4 The Enterprise Edge
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CHAPTER 1
The Service Provider Edge is just a list of the public networks thatfacilitate wide-area connectivity and include:
n Internet service provider (ISP)
n Public switched telephone network (PSTN)
n Frame Relay, ATM, and PPP
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Figure 1-5 puts together the various pieces: Campus, Enterprise Edge,and Service Provider Edge. Security implemented on this model isdescribed in the Cisco SAFE (Security Architecture for Enterprise)blueprint.
CAMPUS BACKBONE
BUILDING ACCESS1st Floor
2nd Floor
3rd Floor
1st Floor
2nd Floor
3rd Floor
1st Floor
2nd Floor
3rd Floor
SERVER FARM
LegacyFile & Print DatabaseE-Mail DNS Directory
ServiceProvider Edge
Enterprise EdgeEnterprise Campus
Managem
ent
Remote Access
WANEdgeDistribution
Internal Router
DMZ Firewall
Web
DatabaseIDC
App Server
Internet Router
Corporate Router
Dial-In
Internal RouterDMZ Firewall
PublicServers
Internet Router
Internal Router VPN
IDS
Internet
PSTN
Internal Firewall
Internal Firewall
Caching
Firewall
PPP
ATM
Frame Relay
BUILDING DISTRIBUITIONBUILDING DISTRIBUITION
BUILDING ACCESS BUILDING ACCESS
4th Floor4th Floor 4th Floor
BUILDING DISTRIBUITION
E-Commerce
Internet
IDC
IDC
IDC
FIGURE 1-5 The Enterprise Composite Model

CHAPTER 1
SONA and IINModern converged networks include different traffic types, each withunique requirements for security, QoS, transmission capacity, anddelay. These include:
n Voice signaling and bearer
n Core application traffic, such as Enterprise Resource Planning(ERP) or Customer Relationship Management (CRM)
n Database transactions
n Multicast multimedia
n Network management
n Other traffic, such as web pages, e-mail, and file transfer
Cisco routers are able to implement filtering, compression, prioritiza-tion, and policing. Except for filtering, these capabilities are referred tocollectively as QoS.
NoteThe best way to meet capacity requirements is to have twice as much band-width as needed. Financial reality, however, usual

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