Services in a Converged WAN : Services in a Converged WAN Accessing the WAN – Chapter 1
Objectives : Objectives Describe how the Cisco Enterprise Composite Model (ECNM) provides integrated services over an Enterprise network.
Describe the key WAN technology concepts.
Frame Relay
ATM
HDLC
Identify the appropriate WAN technologies to use when matching ECNM best practices with typical enterprise requirements for WAN communications.
Purpose and Characteristics of WANs : Purpose and Characteristics of WANs Wide Area Networks provide access to remote locations
WAN Characteristics
Connect devices (or networks) that are geographically separated
Depend on links administered by other agencies (ISP’s)
Generally uses serial connections to service provider equipment
Business Network Growth : Business Network Growth Small Office (single LAN)
Campus (multiple LAN segments)
Branch (WAN)
Distributed
Review – Hierarchal Design Model : Review – Hierarchal Design Model Weaknesses:
Different business needs
Growth can be haphazard
Adds expense and complexity
Cisco Enterprise Composite model : Cisco Enterprise Composite model Enterprise Campus Architecture
Enterprise Branch Architecture
Enterprise Branch Architecture
Enterprise Data Center Architecture
Enterprise Teleworker Architecture Breaks network into:
Physical areas
Logical areas
Functional areas
WAN Technology : WAN Technology WAN technology focuses primarily on Layer 1 and 2
Layer 1 – physical/electrical connectivity (encoding) to communications provider
Layer 2 – framing of data (encapsulation)
Standard organizations: ISO, TIA/EIA
WAN Physical Layer Terms : WAN Physical Layer Terms Customer Premise Equipment
Data Communications Equipment
Data Terminal Equipment
Demarcation Point
Local Loop (last mile)
Central Office
WAN Devices
Modem, CSU/DSU,Access Server, WAN Switch, Core Router
WAN Physical Layer Standards : WAN Physical Layer Standards V.35 is the standard for T1 or E1 connections
Used in all lab activities
EIA-613, High Speed Serial Interface
WAN Data Link Layer Protocols : WAN Data Link Layer Protocols Multiprotocol Label Switching (MPLS)
Data Link Layer Framing - HDLC : Data Link Layer Framing - HDLC Flag – always set to 01111110
Address field – not needed for point-to-point WAN
Control field – identifies if frame has Network Layer data or control bits
Protocol – added in PPP and Cisco-HDLC
WAN Switching : WAN Switching PSTN and ISDN – circuit switched technologies
Frame Relay and ATM – packet switched
Virtual circuits – permanent and switched
WAN Link Connection Options : WAN Link Connection Options
Leased Lines : Leased Lines
Integrated Services Digital Network : Integrated Services Digital Network BRI – Basic Rate Interface
Two 64 kpbs B channels
PRI – Primary Rate Interface
23 B channels
Note: also a commandor D channel
Virtual Private Networks : Virtual Private Networks Allow WAN connections through public networks (Internet)
VPN benefits include cost savings, security, and scalability
VPN Types
Site-to-Site VPNs
Remote Access VPNs
Metro Ethernet : Metro Ethernet IP aware switches allow ISP’s to run Ethernet in the public network
Supports converged technologies
Selecting a WAN Technology : Selecting a WAN Technology List factors to consider when selecting a WAN connection
Summary : Summary A WAN is defined as
A data communications network that operates beyond the geographic scope of a LAN
WAN primarily operate on layer 1 & 2 of the OSI model
WAN technologies include
Leased line
ISDN
Frame relay
X.25
ATM
Summary : Summary Cisco Enterprise Architecture
This is an expansion of the hierarchical model that further divides the enterprise network into
Physical areas
Logical areas
Functional areas
Selecting the appropriate WAN technology requires considering some of the following:
WAN’s purpose
Geographic scope of WAN
Traffic requirements
If WAN uses a public or private infrastructure
Chapter 1 Labs : Chapter 1 Labs Lab 1.4.1: Challenge Review
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