Network Elements and Services

warmersafternoonNetworking and Communications

Oct 23, 2013 (3 years and 7 months ago)

67 views

CS 695 Network Management Techniques

Network Elements and Services

CS 695 Network Management
Techniques

Prof. P. T. Chung

CS 695 Network Management Techniques

Outline


1.
Networking
-

Concepts


2
.
Internet Communication Protocols


3. Network Elements


4. Network Management Related
Protocols

CS 695 Network Management Techniques

1.
Networking
-

Concepts


Network Classifications


Network Technologies


Network Transmission Media


Network Elements

CS 695 Network Management Techniques

Network Classifications


N
etworks


Classified by
Applications


Data Communication Network


Telecommunication Network



N
etworks


Classified by
Distance


LAN (Local Area Network)


MAN (Metropolitan Area Network)


WAN (Wide Area Network)

CS 695 Network Management Techniques

Network Classifications (Conti)


N
etworks


Classified by
Switching


Packet Switching


Circuit Switching



N
etworks


Classified by
Transmission Media


Wired Network


Wireless Network


CS 695 Network Management Techniques

ATM

Network Technologies

LAN

MAN

WAN

Ethernet

Token Ring

Gigabit

Ethernet

ISDN (basic rate)

FDDI

Fast

Ethernet

Frame Relay

MAN & SMDS

Bandwidth

Distance

CS 695 Network Management Techniques

Transmission Media

Media

Wireline

Transmission

Wireless

Transmission

Electric

Conductors

Optical

Fiber

Twisted

Pair

Coaxial

Cable

Mono
-
mode

Multi
-
mode

Radio

Microwave

Satellite

Transmission

Infrared

Laser Links

CS 695 Network Management Techniques

Network Elements

LAN/Internet
E
lements:

o
Repeater

o
Hub

o
Bridge

o
Switch

o
Router

o
Gateway

WAN

Elements:

o
Modem

o
Repeater

o
ADM (
Add
-
Drop Multiplexer
)

o
Cross
-
Connect

o
Switch

o
Multiplexer

o
Concentrator



CS 695 Network Management Techniques

OSI Communication Architecture


Application

Presentation

Session

Transport

Network

Physical

Data Link

Application

Presentation

Session

Transport

Network

Physical

Data Link

Application protocol

Network

Network

Data Link

Data Link

Physical

Physical

Presentation protocol

Transport protocol

Session protocol

Host A

IMP 1

IMP 2

Host B

CS 695 Network Management Techniques

2
.
Internet Communication Protocols


T
he TCP/IP Protocol Architecture


TCP/IP
Layers ( or
TCP/IP
Suite )



Application Layer



Host
-
to
-
host, or transport layer



Internet Layer



Network Access Layer



Physcical Layer


Transport

Internet

Network

Access

Application

PPP

SLIP

RARP

ARP

IP

IGMP

BGP

OSPF

ICMP

RIP

UDP

TCP

SNMP

NNTP

HTTP

DNS

TELNET

SMTP

BOOTP

NTP

FTP

DHCP

TIME

ECHO

Internet Communication Protocol

Data Link

CS 695 Network Management Techniques

IP (Internet Protocol)


Mainly provides multiple routes or Routing
capabilities.


P
rotocol Characteristics:

Connectionless, Unreliable


IP Addressing:


Every host in
TCP/IP
network has one
32
-
bit
IP

address.



140.131.76.1

CS 695 Network Management Techniques

IP Address


length

4
Bytes (32
-
Bit)


IP
address:


Network Address


Subnet


Host Address)


Network

Host

Subnet

Host

IP Address Formats

CS 695 Network Management Techniques

CS 695 Network Management Techniques

CS 695 Network Management Techniques

CS 695 Network Management Techniques

Network Mask


Set 1 for bits in Network Address and
Subnet, and set 0 for other bits in IP
address


Class A


255.0.0.0


Class B



255.255.0.0


Class C



255.255.255.0


IP address


Logical
AND

(Network Mask,
IP

Address)

CS 695 Network Management Techniques

Routers and the IP Addressing Principle


Routers have two or more addresses. One for
each interface.

CS 695 Network Management Techniques

Routing Table

IF ((Mask[i] & Destination Addr) = = Destination[i])

Forward to
NextHop[i]

CS 695 Network Management Techniques

IP Forwarding Process

CS 695 Network Management Techniques


IF ((Mask[i] & Destination Addr) = =
Destination[i])


Forward to
NextHop[i]

CS 695 Network Management Techniques

Port


Each host’s application layer (or processing layer)
may have different application, service, or
resource. Once a host received data from
network, transport layer should have a
mechanism to provide and distinquish network
application service so that it could send data to
correct processing program.



Each upper
-
level communication application
service or program maps to a unique TCP or
UDP Port Number.

CS 695 Network Management Techniques

Common TCP/IP Application Services
and Port Numbers

21

FTP

23

Telnet

25

SMTP

53

DNS

79

Finger

80

HTTP

110

POP3

119

NNTP

123

NTP

53

DNS

67

BOOTP

69

TFTP

161

SNMP

162

SNMP
-
Trap

TCP

UDP

Port
:

1
~
1024

for

Internets

CS 695 Network Management Techniques

3
.
Network Elements



Repeater



Hub



Bridge



Switch


Router


Routing Switch


Gateway



CS 695 Network Management Techniques

Repeater


Operates at Layer 1, the physical layer.


Connects two network segments into one large
segment, or to expand an existing segment.


Enhances data signals and thus can be used to
extend maximum cabling distances.


There is no network intelligence built into a simple
repeater; it is used strictly for signal propagation.

CS 695 Network Management Techniques

Hub


Operates at Layer 1, the physical layer.


Simply a multiport repeater.


Can be used to increase overall network size and
number of nodes on a single segment.


Can isolate faults within the subnet.


Allows you to add stations to a segment without
disrupting the entire network.

CS 695 Network Management Techniques

Bridge


Operates at Layer 2, the data link layer.


Allows networks with different physical signaling, but
with compatible data link addressing schemes, to
communicate.


Helps reduce traffic on a backbone LAN by filtering any
information coming from one segment to another that
does not need to be forwarded through the backbone.


A common use for a bridge is to allow users on an
Ethernet LAN and a Token Ring LAN to communicate
with each other.

CS 695 Network Management Techniques

Bridge Example

Application

Presentation

Session

Transport

Physical

Network

Data Link

Application

Physical

Presentation

Session

Transport

Network

Data Link

Physical

Data Link

Physical

Data Link

Bridge

CS 695 Network Management Techniques

Switch


Operates at Layer 2, the data link layer.


Dispatches data to its destination, which it
determines from the packet’s lower
-
layer media
access control (MAC) address.


Can limit traffic, and does not understand
network protocols.

CS 695 Network Management Techniques

Router


Operates at Layer 3, the network layer.


Connects two networks with different
technologies, and provides an intelligent means
of transferring packets from one network to the
other.


Also forwards traffic among multiple hubs and
bridges.


CS 695 Network Management Techniques

Router Example

Application

Presentation

Session

Transport

Physical

Network

Data Link

Application

Physical

Presentation

Session

Transport

Network

Data Link

Physical

Network

Data Link

Physical

Network

Data Link

Router

CS 695 Network Management Techniques

Routing Switch


Operates at Layer 3, the network layer.


Combines the intelligence of a router with the
efficiency of a switch,


Routing data at higher speeds.


CS 695 Network Management Techniques

Gateway


Operates at Layer 7, the application layer.


Can encompass all seven of the OSI model
layers.


A computing system that can be programmed to
do any number of intricate protocol conversions
and negotiations, such as between IP and IPX.

CS 695 Network Management Techniques

CS 695 Network Management Techniques

4.
Network Management related
Protocols


SNMPv1


SNMPv2C


ICMP


ARP/RARP


DHCP


CS 695 Network Management Techniques

SNMPv1


(Simple Network Management Protocol version 1)


The most common management protocol in use in data networks.


Provides a means of obtaining information from, and sending
information to, network devices.


Based on the manager
-
agent model.


Uses Management Information Bases (MIBs) to exchange
information between the manager and the agent.


Using the SNMP protocol, a manager can query and modify the
status and configuration information on each managed device by
making requests to the agent running on the managed device.


All commands use the UDP/IP protocol, which means that
communication between the manager and the agent is
connectionless.


SNMP operates at Layer 7, the application layer.

CS 695 Network Management Techniques

SNMPv2C (version 2)


SNMPv2C includes the basic functions of SNMPv1.


Adds


new message types,


standardized multi
-
protocol support,


enhanced security,


new MIB objects, and


a way to co
-
exist with SNMPv1.


SNMPv2C is useful for the retrieval of large amounts of
management information using fewer network resources.

CS 695 Network Management Techniques

ICMP

(Internet Control Message Protocol)


ICMP is the part of IP that handles error and control
messages.


ICMP operates at Layer 3, the network layer.


ICMP supports an
echo
function, which sends a packet
on a round
-
trip between two hosts.


Ping
, which sends a signal to see if an interface is up
and running, is based on ICMP
echo
.


ICMP can also send an address mask request that
returns the address of the subnet mask on the remote
system. This feature is important for non
-
SNMP devices.

CS 695 Network Management Techniques

ARP/RARP

(Address Resolution Protocol / Reverse ARP)


ARP/RARP are used at Layer 2, the link layer,


ARP is used to map an IP address to a MAC (or
link level, or hardware) address.


RARP is used to map a MAC address to an IP
address.

CS 695 Network Management Techniques

DHCP

(Dynamic Host Configuration Protocol)


DHCP allows IP addresses to be allocated on a temporary
basis (a lease).


When the lease for an IP address expires, the address can
be reused by a different node.


This is useful in environments supporting mobile users who
connect to the network with a laptop from many different
places.


This helps alleviate the problem of limited IP addresses and
simplifies TCP/IP client configurations.