1. Wide area networks
Chapter 11

2. objectives Upon completion of this chapter, you should be able to:
Understand how to connect to a WAN
Identify how data moves in the WAN
Identify common WAN services
Configure a PPP WAN link
Connect to a DSL network
Create and configure a remote access connection
Configure a server for remote access connections
Configure a RADIUS solution to provide AAA for remote access

3. Network+ Objectives
1.3 Explain the concepts and characteristics of routing and switching
Distributed switching
Packet-switched vs. circuit-switched network
2.5 Compare and Contrast WAN technologies
Service type
ISDN, T1/T3, E1/E3, OC-3 - OC-192, Metropolitan Ethernet, PRI
Transmission mediums
Copper, Fiber
Characteristics of service
MPLS, ATM, Frame relay, SIP trunk
Termination
Demarcation point, CSU/DSU

4. 11.1
Wan structure

5. wan 2 or more LANs that connect together
Usually the ISP provides the WAN devices
Cloud is represented as another network that you don’t manage.
In this scenario, your network leads to the service provider (sometimes called the Central Office) which connects to the Internet or the Public Switched Telephone Network.
The service provider is responsible for everything between the demarcs.
The local loop is the connection from your demarc to the ISP
Demarc is the end of your network and beginning of the service provider network.
You are responsible for everything within your network, AKA CPE (customer premise equipment).

6. Csu/dsu
Device that connects your line to the WAN or service provider line
Acts like a modem
A cable modem & DSL modem are CSU/DSUs.
Channel Service Unit/ Data Service Unit
CSU terminates the signal coming from the Internet and the DSU converts the signal into a format to be read by your router.

7. Moving through cloud Circuit switching Packet switching
Dedicated path from one end to other
May be permanent or established for each transmission (like a phone call)
NOT COMMON
Packet switching
Data broken into packets
Takes different paths
Service provider makes sure all packets arrive & are reassembled
MOST COMMON
Packet switching: each packet is routed through the WAN

8. Establishing a wan connection- t & e
T1 LINE
24 channels on 2 pairs of wire
1.544Mbps (64k each)
T3 LINE
672 channels
44.7Mbps (64k each) E1
32 channels (64k each)
2.047Mbps E3
16 channels (2.048Mbps each)
34.368Mbps
T-Carrier: Digital using copper cable; Voice & data US
EUROPE

9. Establishing a wan connection- optical
OC specs for speed over SONET
OC-1 Base Rate: 51.84Mbps
Signals use DWDM
Multiplexes multiple optical signals on one cable
OC- Optical Carrier
SONET- Synchronous Optical Network
OC-1 is the base rate. After that, multiply the base rate times the OC number to figure out the speed.
DWDM: Dense Wavelength Division Multiplexing (uses different colors of light)
A multiplexer (joins signals) & demultiplexer (splits signals back out)

10. Wan services- PSTn & isdn
POTS/PSTN
56k analog dial-up
ISDN (not common in US)
Connection to the WAN service provider
BRI
Analog over telephone line with J45
2 B data channels at 64k
1 D signaling channel at 16k
128kbps for data (144kbps total)
PRI
Uses digital T1 line at 1.544Mbps
23 B data channels, 1 D signaling channel at 64k each
Public Switched Telephone Network
Plain Old Telephone Service
ISDN still used in Europe.
T1 line=1.544Mbps
T3 line= 44.7Mbps

11. Wan services- frame relay (OLD)
Packet switching
Uses T1 lines
Permanent virtual circuit through the WAN
Point-to-point or multipoint connection
It’s like you have a dedicated connection to the other end.
Multipoint is a single virtual circuit that can go to three separate locations.
When using Frame Relay, you get a CIR (Committed Information Rate) which is how much guaranteed bandwidth/data you can send through the network.
Frame Relay drops packets when it is congested.

12. Wan services- atm Packet switching
Divides packets into cells at a fixed size
You get a constant rate
Used for time-sensitive transmissions such as audio or video
Constant rate happens because the WAN does not need to figure out how long the data should be. It will always be 53 bytes.
Switches in the ATM WAN read the cells.
Does not drop packets when congested. It ensures delivery.

13. Wan services- metro ethernet
Routers & switches using fiber in a MAN
Tends to be faster than other WAN services because it stays within the ISP WAN
Sets up a point to point (or even multipoint) within a MAN.

14. activity
TestOut Practice Questions (15)

15. 11.2
Wan connections
Process of securing devices

16. Ppp connection
Used to encapsulate and transport data from LAN to ISP over dedicated leased lines
Layer 2
PPP is universal*
Authentication with PAP or CHAP
Cisco routers use HDLC by default; if you are NOT connecting from Cisco to Cisco router, use PPP
PPP uses 2 protocols to establish & maintain the link;
LCP (establishes, maintains and ends the connection) & detects errors at LAYER 2 and provides authentication (PAP/CHAP)
NCP is control protocols for the LAYER 3 protocol (IPCP for IPv4 & IPv6CP for IPv6)
PAP- Password Authentication Protocol (2-way); clear text; username/password sent & acknowledged if correct
CHAP- Challenge Handshake Authentication Protocol (3-way); hash is sent (this is not encrypted but a random number); authentication request, challenge, hashed password, authentication acknowledgement

17. acivity TestOut Lab 11.2.4- Configure a PPP WAN Link
TestOut Practice Questions (8Q)

18. Internet service facts
Info
Dial-up
56k; phone line/number to dial in; can’t use voice & data at same time
DSL
Digital over POTS line; Distance limits; ADSL most common (voice & data)
Cable
Data over cable service (DOCSIS); cable modems; high speed; bandwidth shared with neighbors
Satellite
Available anywhere using dish & clear view of sky; weather can disrupt service; high latency
Cellular
Uses GSM or CDMA networks; coverage may be weak depending on provider coverage; 3G, 4G LTE
Complete TestOut LAB Connect to a DSL Network
TestOut Practice Questions (15)

19. 11.4
Remote access
Process of securing devices

20. Remote access
Ways to connect to remote sites or main office while traveling
PSTN- slow & rarely used anymore
Internet
After you connect, negotiate the connection
PPP (Point-to-Point Protocol)/PPPoE
Used to establish the physical remote connection
They decide which protocols they’ll use
You get an IP address from the remote network
Can use authentication (CHAP, MS-CHAP, EAP)
Authorization (what client has access to)
PPPoE is what would be used to connect to a DSL ISP Broadband provider.
Imagine old dial-up connections like a conversation over the telephone between you and your boss. It's just the two of you who can participate in the conversation. But what if your boss wanted to speak to all your team? If your conversation would be a dial-up connection, all your team would have to gather around the same phone earpiece. It would make for a funny and ineffective conversation, wouldn't it? PPP is just like that: only one to one connections are possible.
PPPoE changed that and it allowed more client devices to use the same network in order to connect to one single server. It's like your boss speaking with all your team, but you would have a loudspeaker so that you don't have to crowd around one small earpiece.
PPPoE is one of the most preferred means of delivering DSL Internet access. Your ISP will rent or sell you a modem-router.
Comcast modems connect to their hub and gets encapsulated as IP packets.

21. More remote access More and more clients use remote access
Need more servers to handle connections
Use an AAA server
One server with all of the policies instead of copying policies to many servers
When you connect remotely, authorization requests forwarded to AAA server for approval
AAA- Authentication, Authorization, Accounting (keeps logs of access)
The AAA server can be a RADIUS server which handles the authentication & authorization. It uses UDP.
When you dial in to the ISP you must enter your username and password. This information is passed to a RADIUS server, which checks that the information is correct, and then authorizes access to the ISP system.
A TACACS+ server (up to date version) can put all three into one server or separate servers. It uses TCP and encryption.

22. Aaa Authentication is the process of proving identity
After devices agree on the authentication protocol to use, the logon credentials are exchanged & logon is allowed or denied
EAP allows authentication using a variety of methods, including passwords, certificates, and smart cards
Authorization identifies the resources that a user can access
Authorization can restrict access based on the following parameters:
Time of day
Type of connection
Restrict access to specific servers
Accounting tracks or logs the use of the remote access connection
Often used by ISPs to bill for services based on time spent or the amount of data downloaded
Two common AAA Server Solutions:
RADIUS
Used by Microsoft servers for centralized remote access administration.
Combines authentication and authorization using policies to grant access.
Uses UDP.
Encrypts only the password.
Often uses vendor-specific extensions. RADIUS solutions from different vendors might not be compatible.
When implementing a RADIUS solution, configure a single server as a RADIUS server and configure all remote access servers as RADIUS clients.
TACACS+:
Provides three protocols, one for authentication, one for authorization, and one for accounting. This allows each service to be provided by a different server.
Uses TCP port 49.
Encrypts the entire packet contents.
Supports more protocol suites than RADIUS.

23. activity
TestOut Practice Questions (14Q)

24. 11.5
Wan troubleshooting
Process of securing devices

25. troubleshoot Ping test On Cisco router, check line status
Interface status up or down (Layer 1)
Protocol status up or down (Layer 2)
SHOW IP INT BRIEF command
Down, Down- bad cable, no cable, powered off device
Up, Down- make sure you’re using the same encapsulation on both sides (HDLC to HDLC, PPP to PPP), DCE side needs clock rate set, incorrect PAP/CHAP authentication
Up, Up working properly
A failed PING or TRACEROUTE means layer 1, 2 or 3 problem.

26. activity
TestOut Practice Questions (9Q)

27. Review & study Complete the study guide handout Complete TestOut
Practice in Packet Tracer
Jeopardy review

28. Wide area networks
Chapter 11