1. 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

2. Student Check-In Are there any unanswered questions from last week?
Are you ready to begin the programming portion next week?
Visual Studio?
Programming book?
Do you have any questions about your research paper topic?
Quick questions?
me for longer questions
IS Week 2

3. Chapter 7
Backbone Networks

4. 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…

5. Switches and Routers

6. 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

7. 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

8. Chapter 8
Wide Area Networks

9. 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

10. T-Carrier & SONET Digital Hierarchy

11. VPN Architecture

12. Chapter 9
The Internet

13. 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

14. Basic Internet Architecture

15. 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

16. 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

17. 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

18. End
Questions?
IS Week 2