Transcript Slide 1
Managing Network connections
Network Cabling
Ethernet Topology
• Bus topology
– Connects each node in a line
– Has no central connection point
• Star topology
– Connects all nodes to a centralized hub
– More popular; easier to maintain
Ethernet Topology
Ethernet Using Star Topology
Ethernet Using Star Bus Topology
Repeaters
Wireless LANs (WLANs)
• Make connections using a wireless NIC
• Communicate directly or connect to a LAN by way of
a wireless access point (AP)
• Popular where cables are difficult to install
• Slower than wired networks
• Security is an issue
• Standards
– 1999 IEEE 802.11b (Wi-Fi, AirPort)
– Bluetooth
Bridges and Switches
• Bridges
– Send broadcast messages; not
good for large networks
– Effective at separating highvolume areas on a LAN
– Work best when used to
connect LANs that usually do
not communicate outside
their immediate network
• Switches
– Send a packet only to network
segment for which it is
destined
Bridges Compared with Switches
MAC Addresses
• Unique addresses that are permanently embedded
in a NIC and identify a device on a LAN
• Expressed as six pairs of hexadecimal numbers and
letters
• A local address
• Used at the lowest (physical) networking level for
NICs and other devices on the same network to
communicate
Architectural Overview of the TCP/IP
12
The TCP/IP Protocols
• The TCP/IP protocols
– Provide networking connectivity support for
computers (called hosts) on LANs and WANs
– Follow a set of standards for how computers
communicate and how networks are
interconnected
– Follow the four-layer Department of Defense
(DOD) model
Internet Protocol
• Internet Protocol (IP) does the actual delivery
of datagrams.
• IP adds the following header fields to each
packet:
Source IP Address
Destination IP Address
Protocol
Checksum
Time to Live (TTL)
14
IP Addressing
• Every host on a TCP/IP network must have a
unique IP address (a 32-bit number that
identifies both the host and the network the
host is located on).
• IP addresses are expressed in dotted-decimal
format, such as 192.168.123.132.
• Each set of four dotted-decimal numbers
represents eight bits of the binary address.
– The addresses range from 00000000 to 11111111,
or, in decimal notation, from 0 to 255.
15
IP Addressing (Cont.)
• An IP address is accompanied by a subnet mask.
• The subnet mask, when compared to the IP address,
identifies the part of the IP address that is the network
identifier and the part that is the host identifier.
– The 1s identify network bits and the 0s identify host bits.
– In the subnet mask 255.255.0.0, the first 16 bits
(2 octets)
are the equivalent of all ones in binary form.
• The first two octets of the IP address are the network identifier.
• The last two octets represent the host identifier.
16
IP Address Classes
17
IP Address Ranges for Private
Networks
Class
Network Addresses
A
10.0.0.0 through
10.255.255.255
B
172.16.0.0 through
172.31.255.255
C
192.168.0.0 through
192.168.255.255
18
Using Ipconfig.exe
• Use Ipconfig.exe to view the TCP/IP
configuration settings on a host, including IP
address, subnet mask, and default gateway.
– At the command prompt, type ipconfig or ipconfig
/all and then press Enter.
– Use the /all parameter to display more
information.
• Running Ipconfig is an easy way to view the IP
address and other parameters that the DHCP
server has assigned to your computer.
19
Using Ping
• Ping is a command-line utility that uses Echo Request
messages to determine if the TCP/IP stack of another
computer on the network is functioning normally.
• From a command prompt, type ping target (where
target is the IP address or the name [DNS or NetBIOS,
Example ping www.google.co.in] of the computer you
are trying to contact).
– A successful ping results in several reply messages from the
target computer.
– If the ping fails, one or both computers might have a
networking hardware or software problem.
– Example c:\> ping 192.168.1.2
20
Using Traceroute
• Tracert.exe, a variant of Ping, displays the path
that packets take to their destination.
• From a command prompt, type tracert target
(where target is the IP address or the name
[DNS or NetBIOS] of the target computer).
• Use Tracert.exe to isolate the location of a
network communications problem,
particularly when a router is suspected.
• Example C:\> tracert.exe 192.168.1.2
21
Using Pathping
• Pathping is a route tracing tool that
– Sends packets to each router on the way to a final destination
over a period of time
– Computes results based on the packets returned from each hop
• You can use Pathping.exe to isolate problems because it
shows the degree of packet loss at any given router or
link.
• From the command line, type pathping target (where
target is the IP address or the name [DNS or NetBIOS] of
the target computer).
• Example C:\> pathping.exe 192.168.1.2
22
Using Route.exe (Cont.)
• The ROUTE PRINT command displays the
current contents of the routing table.
• To create a new entry, use ROUTE ADD with
parameters that specify the values for the
entry.
• Example C:\> route.exe 192.168.1.2
23
Using Route.exe
• Use Route.exe to create, delete, or modify static routes in
a routing table on a computer running Windows 2000.
• Route.exe uses the following syntax:
ROUTE [-f] [-p][command[destination]
[MASK netmask] [gateway]
[METRIC
metric] [IF interface]]
• The Route.exe command variable takes one of four
values:
PRINT
ADD
DELETE
CHANGE
24
Using Arp.exe
• IP uses ARP to discover the hardware address that each
datagram is transmitted to.
• Resolved addresses are stored in an ARP cache.
• Use Arp.exe to view or change the contents of the ARP
cache.
• Arp.exe uses the following syntax:
ARP [-a {ipaddress}] [-n ipaddress] [s ipaddress hwaddress {interface}]
[-d ipaddress {interface}]
25
Using Netstat.exe
• Netstat.exe is a Windows 2000 command-line
utility that displays information about
– The current network connections of a computer
using TCP/IP
– The traffic generated by various TCP/IP protocols
• Netstat.exe uses the following syntax:
NETSTAT [interval] [-a]
protocol] [-n] [-e] [-r] [-s]
[-p
26
Using Nbtstat.exe
• Nbtstat.exe is a Windows 2000 command-line
utility that displays information about the
NetBIOS over TCP/IP connections used by
Windows 2000 when communicating with
other Windows computers on a TCP/IP LAN.
• Nbtstat.exe uses the following syntax:
NBTSTAT [-a name] [-A ipaddress]
[-c] [-n] [-r] [-R] [-s] [-S] [-RR]
• The parameters for Nbtstat.exe are casesensitive.
27
Using Nslookup.exe
• Nslookup.exe is a Windows 2000 commandline utility that enables you to generate DNS
request messages and transmit them to a
specific DNS server on the network.
• Nslookup.exe uses the following syntax:
NSLOOKUP DNSname DNSserver
– DNSname specifies the DNS name you want to
resolve.
– DNSserver specifies the DNS name (or IP address
of the DNS server) you want to query for the
name you want to resolve.
28
Try your own…
LEARN , LEAP , LEAD…