Ken Gunnells, Ph.D. - Networking Paul Crigler - Programming IS 591 Introduction to Networking and Computer Programming University of Alabama at Birmingham Ken Gunnells, Ph.D. - Networking Paul Crigler - Programming Chapters 7 – Backbone Networks 8 – Wide Area Networks 9 – The Internet

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Chapter 7 Backbone Networks

Backbone Networks High speed networks linking an organization’s separate LANs High speed circuits that make enables information transfer between Buildings, Departments, MANs Hardware devices connected with network cables (Optical Fiber or UTP) to…

Switches and Routers

Switches and Routers Switches Routers These use the data link layer address (e.g. Ethernet) to forward packets between network segments that use the same data link and network protocol Routers Operates at the network layer to examine the destination address (e.g. IP) of the network layer. Chooses the “best” route for a packet (via routing tables) and forwards only those messages that need to go to other networks Performs more processing

Gateways Connect two or more networks that use the same or different data link and network protocols. Operating at network layer, gateways are more complex than switches or routers

Chapter 8 Wide Area Networks

Wide Area Networks (WANs) Connect BNs and LANs across longer distances, often hundreds of miles or more Typically built by using leased circuits from common carriers such as AT&T Circuit-Switched Networks (ISDN or POTS) Relatively cheap but slow Dedicated-Circuit Networks (T services or SONET/optical) Flat fee per month, fast Packet-Switched Networks Multiple connections to multiple computers, at same time over one physical circuit Virtual Private Networks (Tunnels) over public internet Encapsulates and encrypts IP packets Low cost and flexible Unpredictable conflicts with internet traffic

T-Carrier & SONET Digital Hierarchy

VPN Architecture

Chapter 9 The Internet

Internet’s 3 Tiers of ISPs Tier 1 ISPs: Provide service to tier 2 & 3 ISPs Connect to other Tier 1 ISP through Network Access Points (~12 in US, Run by AT&T, Sprint, etc) Tier 2 ISPs: Provide service to local ISPs Metropolitan Area Exchanges connect Tier 2 IPs Tier 3 ISPs: Sell access to individuals ISPs usually do not charge peers to carry packets Higher level ISPs charge lower level ISPs Tier 3 ISPs charge individuals and corporate users

Basic Internet Architecture

Connecting to an ISP Done by through ISP’s Point of Presence (POP) A place at which ISP provides service to its customers Individual users Typically through cable or DSL Userid and password checked by Remote Access Server (RAS) Once logged in, the user can send packets DSL modem & Cable modem handles login Corporate users Typically access the POP using a T-1, T-3 or ATM OC-3 connections provided by a common carrier Cost = ISP charges + circuit charges

Internet Backbones Backbone circuits for national ISPs OC-48 and OC-192 (10 Gbps) becoming more common Larger backbones converting to OC-192 (10 Gbps) OC-768 (40 Gbps) and use OC-3072 (160 Gbps) in experiment stage Aggregate Internet traffic Growing rapidly Internet traffic was about 80 Terabits per second (Tbps) in 2011. NAPs and MAEs becoming bottlenecks Requiring larger and larger switches

Internet Access Technologies Most methods today are commonly called “broadband access”, meaning “high speed” Digital Subscriber Line (DSL and AT&T U-Verse) High speed data over traditional phone lines Point-to-point Cable Modems by cable TV companies High Speed data over Coax wire Greater bandwidth than phone wire, but… Shared bandwidth with other users in the area Fiber to the Home Very high speed data over fiber optic cable Relatively few have this service

End Questions? IS 591 - Week 2