1. Chapter 8 – Data switching and routing
Data different than voice
Already digital – voice must be converted to digital from analog
Can tolerate delay usually – voice can’t tolerate delay
Continuous stream or bursts – voice is a stream
Data can flow at any speed – digitized voice is based on 64kbps
Data highly susceptible to errors – voice not so much
Data uses many protocols
Data Packets
Header and payload
Connection-oriented
Connectionless-oriented

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4. Chapter 8 – Data switching and routing
Open Systems Interconnect Model (OSI)

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Internet Protocol (IP)
Layer 3 of OSI Model
Connectionless packet standard – very flexible
IPv4 and IPv6
IPv4 Packet structure

7. Chapter 8 – Data switching and routing
IP routing not routeing

8. Chapter 8 – Data switching and routing
Routers
Routers connect LAN’s forming a WAN
Static routing
Routing protocol
AS – autonomous system – network of routers owned by one organization
AS routing
Interior Gateway Protocol (IGP) – routing within an AS
Exterior Gateway Protocol (EGP) – routing between AS

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IP doesn’t provide data transfer well at layer 3
Transport Layer 4 used for data transfer
Transmission Control Protocol (TCP)
Connection-oriented
User Datagram Protocol
Connectionless-oriented
TCP numbers IP packets (datagrams) at sending and receiving endpoints
Orders them correctly
Request retransmission of packets if needed
Monitors flow rate of packets

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UDP connectionless
No retransmission
No delay
Better suited for voice and video
Web page request – OSI layers

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The “Internet” is a collection of IP networks connecting to each other – not one single public Internet backbone
Based on consortium of users, academics, and data equipment manufacturers – Internet Engineering Task Force (IETF)
Originated (ARPANET) US Dept. of Defense 1960s
TCP added in 1983 – information sharing
HTTP – world wide web – 1991
Multiple Tier one providers own networks
Tier 2, 3, etc. providers
Peering points
Public
Private
Internet of Things (IOT)

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Voice over IP (VoIP)
Very useful for business with multiple locations

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Wide Area Network (WAN) Types
Private Line
Dedicated full bandwidth end to end
Can run any protocol on the circuit
Expensive
Many circuits to manage at HQ
Virtual Private Network (VPN)
Uses public internet
Tunnel created back to HQ site
Software client for remote user
Encrypted for security
Scaleable

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Multi-protocol Label Switching (MPLS)
Shared backbone connection (but not over public internet)
Routers use labels on IP packets to create a “virtual path” through the network
Fast switching through network
Can scale to many sites
One circuit to manage at HQ site

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Local Area Network (LAN)

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Ethernet
Carrier-sense multiple-access with collision detection (CSMA/CD)
Wireless LAN

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Cloud Computing