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Chapter Six
Networking
Hardware
Network Interface Cards (NICs)
 Connectivity devices enabling a workstation,
server, printer or other node to receive and
transmit data over the network media
 Sometimes called network adapters
 NICs are physical and data link layer
devices
Network Interface Cards (NICs)
Types of NICs
 Industry Standard
Architecture (ISA)
 MicroChannel
Architecture
(MCA)
 Extended Industry
Standard
Architecture (EISA)
 Peripheral
Component
Interconnect (PCI)
FIGURE 6-1 Four primary bus architectures
Network Interface Cards (NICs)
 NICs may connect to interfaces other than a
PC’s bus. For example:
– For laptop computers, Personal Computer Memory
Card International Association slots may be used to
connect NICs
• PCMCIA
• Also called PC card
• Developed in the early 1990s to provide a standard
interface for connecting any type of device to a
portable computer
Network Interface Cards (NICs)
FIGURE 6-3
Typical
PCMCIA NIC
FIGURE 6-4
Parallel port
NIC
Network Interface Cards (NICs)
FIGURE 6-5
Wireless NIC
and
transceiver
FIGURE 6-6
Ethernet NICs for
printers
Network Interface Cards (NICs)
 Installing NICs
– Installing hardware
– Configuring software
• Installing driver—software the tells OS how to
communicate with NIC
• Specifying IRQ, memory range, I/O port
– Configuring firmware
• Utilities supplied with NIC that enables you to write
configuration changes to the EPROM chip on the
NIC card
Installing and Configuring NIC
Software
 After NIC is
physically
installed, restart
the PC
 The driver for the
NIC card must be
installed and
configuration
information
entered
Repeaters
 Connectivity device that regenerates and
amplifies an analog or digital signal
FIGURE 6-14
Repeater
Hubs
 Multiport repeater
containing one port
that connects to a
network’s backbone
and multiple ports
that connect to a
group of
workstations
Hubs
 Passive hubs
– Only repeats signal
 Active hubs
– Regenerate or amplify
signal
 Intelligent hubs
– Possesses processing
capabilities
 Standalone Hubs
– Serves a workgroup of
computers that are
separated from the rest of
the network
 Stackable Hubs
– Designed to be linked
with other hubs in a
single
telecommunications
closet
Modular Hubs and
Intelligent Hubs
 Modular hub
– Provide a number of interface options within
one chassis
• Connection point for networks using with different
cabling, e.g., 10base2 and 10baseT
 Intelligent hubs
– Also called managed hubs
– MIB (management information base)
• Collection of data used by management programs to
analyze network performance
Choosing the Right Hub
 Performance
 Cost
 Size and growth
 Security
 Management benefits
 Reliability
Bridges
 Reduce network
traffic bottleneck
 Regenerate signals
to extend network
lengths
 Operate at the Data
Link Layer of the
OSI model because
they have to read
packet addresses
Bridges
 Filtering database
– Collection of data created and used by a bridge that
correlates the MAC addresses of connected
workstations with their locations
– Also known as a forwarding
Segment 1
table
Bridge
Segment 2
Bridges
 Transparent Bridging
– Method used on most Ethernet networks
 Source Route Bridging
– Method used on most Token Ring networks
 Translation Bridging
– Method that can connect Token Ring and
Ethernet networks
Switches
 Switches subdivide a
network into smaller
logical pieces
 Collision domain
– Portion of a LAN
encompassing
devices that may
cause and detect
collisions among
their group
 Switches are layer 2
devices
Switches
 Switch Methods
– Cut-through mode—switch reads only the
header to determine where to forward the
packet.
– Store and forward mode—switch reads the
entire packet and checks for accuracy before
forwarding
Using Switches to Create VLANs
 Virtual local area
networks (VLANs)
– Means by which a
switch can
logically group a
number of ports
into a broadcast
domain
Higher-Layer Switches
 Switch capable of interpreting Layer 3 is called
a Layer 3 switch
 Switch capable of interpreting Layer 4 is called
a Layer 4 switch
 Higher-layer switches may also be called
routing switches or application switches
Routers
 Routers connect two or
more networks
 Consist of hardware and
software
– Hardware
• Network server, separate
computer, special black box
• Physical interface for various
networks
– Software
• Operating system and Routing
protocol
 Routers operated at the
Network layer
Routers
 Can connect dissimilar LANs and WANs
running at different transmission speeds
and using a variety of protocols
 Read the network address information in a
packet
 Calculates the optimal path to a particular
network
– Reroute packets if a path is not available
 Routing tables stored in the router list all
known addresses and possible paths
How do Routers Select Routes
 Dynamic route selection
– Routers continually adjusts the routes based on
network conditions
 Static route selection
– Route is designated in a table and router cannot
vary from that route
Router Features and Functions
 Filter out broadcast transmission to alleviate network




congestion
Prevent certain types of traffic from getting to a
network
Provide high network fault tolerance through
redundant components
Monitor network traffic and report statistics to a MIB
Diagnose internal or other connectivity problems and
trigger alarms
Routers
Routing Protocols
 Means by which routers communicate with
each other about network status
 Routing protocol characteristics
– Convergence time
• The time it takes for a router to recognize a best path
in the event of a change or outage
– Bandwidth overhead
• Burden placed on an underlying network to support
the routing protocol
Routing Protocols
 RIP (Routing Information Protocol) for IP and
IPX
 OSPF (Open Shortest Path First) for IP
– Best path refers to the most efficient route from one
node on a network to another
 EIGRP (Enhanced Interior Gateway Routing
Protocol) for IP, IPX, and AppleTalk
 BGP (Border Gateway Protocol) for IP
Brouters and Routing Switches
 Bridge router
– Also called a brouter
– Industry term used to describe routers that take
on some characteristics of bridges
 Routing switch
– Another term for a Layer 3 or Layer 4 switch
Gateways
 Combination of networking hardware and
software that connects two dissimilar kinds of
networks
–
–
–
–
E-mail gateway
IBM host gateway
Internet gateway
LAN gateway