increases. Also, individual users control access
to the resources on their computers, which means security may
be difficult to maintain. The client/server model of networking
can be used to overcome the limitations of the peer-to-peer
network. Lab Activity Lab Exercise: Building a
Peer-to-Peer Network This lab is to create a simple
peer-to-peer network between two PCs, identify the proper cable
to connect the two PCs, configure workstation IP address
information, and test connectivity using the ping command.
Web Links Peer-to-Peer http://searchnetworking.techtarget.com/
sDefinition/0,,sid7_ gci212769,00.html
Content
5.1 Cabling the LAN 5.1.13
Client/server In a client/server arrangement, network
services are located on a dedicated computer called a server.
The server responds to the requests of clients. The server is a
central computer that is continuously available to respond to
requests from clients for file, print, application, and other
services. Most network operating systems adopt the form of a
client/server relationship. Typically, desktop computers
function as clients and one or more computers with additional
processing power, memory, and specialized software function as
servers. Servers are designed to handle requests from many
clients simultaneously. Before a client can access the server
resources, the client must be identified and be authorized to
use the resource. This is done by assigning each client an
account name and password that is verified by an authentication
service. The authentication service acts as a sentry to guard
access to the network. With the centralization of user
accounts, security, and access control, server-based networks
simplify the administration of large networks. The
concentration of network resources such as files, printers, and
applications on servers also makes the data generated easier to
back-up and maintain. Rather than having these resources spread
around individual machines, resources can be located on
specialized, dedicated servers for easier access. Most
client/server systems also include facilities for enhancing the
network by adding new services that extend the usefulness of
the network. The distribution of functions in the client/server
networks brings substantial advantages, but it also incurs some
costs. Although the aggregation of resources on server systems
brings greater security, simpler access and coordinated
control, the server introduces a single point of failure into
the network. Without an operational server, the network cannot
function at all. Servers require a trained, expert staff to
administer and maintain. This increases the expense of running
the network. Server systems also require additional hardware
and specialized software that add to the cost. Figures and
summarize the advantages and disadvantages of peer-to-peer vs.
client-server. Lab Activity Lab Exercise: Building a
Hub-based Network This lab is to create a simple network with
two PCs using a hub, identify the proper cable to connect the
PCs to the hub, configure workstation IP address information,
and test connectivity using the ping command. Lab
Activity Lab Exercise: Building a Switch-based Network This
lab is to create a simple network with two PCs using a switch,
identify the proper cable to connect the PCs to the switch,
configure workstation IP address information, and test
connectivity using the ping command. Web Links
Client/Server http://searchnetworking.techtarget.com/sDefinition/ 0,
,sid7_gci211796,00.html The Basic of Switching
http://www.vtac.org/Tech/TDbasics_of_ switching.htm
Content 5.2 Cabling the WANs
5.2.1 WAN physical layer The physical layer
implementations vary depending on the distance of the equipment
from the services, the speed, and the type of service itself.
Serial connections are used to support WAN services such as
dedicated leased lines that run Point-to-Point Protocol (PPP)
or Frame Relay. The speed of these connections ranges from 2400
bits per second (bps) to T1 service at 1.544 megabits per
second (Mbps) and E1 service at 2.048 megabits per seconds
(Mbps). ISDN offers dial-on-demand connections or dial backup
services. An ISDN Basic Rate Interface (BRI) is composed of two
64 kbps bearer channels (B channels) for data, and one delta
channel (D channel) at 16 kbps used for signaling and other
link-management tasks. PPP is typically used to carry data over
the B channels. With the increasing demand for residential
broadband high-speed services, DSL and cable modem connections
are becoming more popular. For example, typical residential DSL
service can achieve T1/E1 speeds over the existing telephone
line. Cable services use the existing coaxial cable TV line. A
coaxial cable line provides high-speed connectivity matching or
exceeding that of DSL. DSL and cable modem service will be
covered in more detail in a later module. Interactive Media
Activity Drag and Drop: WAN Physical Layer Implementation
After completing this activity, the student will be able to
identify the components in the WAN physical layer. Web
Links WAN Speeds http://www.webwisdom.com/edu_content/
cps640fall00/ lectures/module3/WAN/ sld008.htm
Content
5.2 Cabling the WANs
5.2.2 WAN serial connections For long distance
communication, WANs use serial transmission. This is a process
by which bits of data are sent over a single channel. This
process provides more reliable long distance communication and
the use of a specific electromagnetic or optical frequency
range. Frequencies are measured in terms of cycles per second
and expressed in Hertz (Hz). Signals transmitted over voice
grade telephone lines use 4 kilohertz (kHz). The size of the
frequency range is referred to as bandwidth. In networking,
bandwidth is a measure of the bits per second that are
transmitted. For a Cisco router, physical connectivity at the
customer site is provided by one of two types of serial
connections. The first type of serial connections is a 60-pin
connector. The second is a more compact ‘smart serial’
connector. The provider connector will vary depending on the
type of service equipment. If the connection is made directly
to a service provider, or a device that provides signal
clocking such as a channel/data service unit (CSU/DSU), the
router will be a data terminal equipment (DTE) and use a DTE
serial cable. Typically this is the case. However, there are
occasions where the local router is required to provide the
clocking rate and therefore will use a data communications
equipment (DCE) cable. In the curriculum router labs one of the
connected routers will need to provide the clocking function.
Therefore, the connection will consist of a DCE and a DTE
cable.
Content 5.2 Cabling the
WANs 5.2.3 Routers and serial connections