Transcript Token Ring Cards - Personal.psu.edu

Ethernet
•
•
•
•
Need for standards
Project 802 (1980, February)
Easy to install
Economical
4/5/2016
Chapters 4 & 5
1
Ethernet
MAC Address
4/5/2016
Chapters 4 & 5
2
Other Forms of Ethernet
• FOIRL [Fibre over inter repeater links]
• user to connect repeaters together in order
to get greater distances
• maximum of 1Km
• 10BaseF
4/5/2016
Chapters 4 & 5
3
Other Forms of Ethernet
•
•
•
•
fiber to desktop
applies to 10Mbps CSMA/CD
star network topology
Comprised of 10BaseFB, 10BaseFL,
10BaseFP
4/5/2016
Chapters 4 & 5
4
10BaseFB Synchronous
Backbone
•
•
•
•
also known as 10BaseFA
2Km per segment
30 repeater hops allowed
no connection to desktop computers
4/5/2016
Chapters 4 & 5
5
10BaseFL Asynchronous Active
•
•
•
•
also known as 10BaseFF
connects repeaters to DTE's
FOIRL compatible
2Km segment
4/5/2016
Chapters 4 & 5
6
10BaseFP Passive
• passive star topology
• non FOIRL compatible
• 1Km segments
4/5/2016
Chapters 4 & 5
7
100 Megabit Ethernet
• 100Base-X
• Comes from Grand Junction Networks
• supported by companies like 3Com, Intel
and Sun Microsystems
• backward compatible with 10Mbps Ethernet
• and uses the CSMA/CD protocol
• is designed to work using the existing cable
types
4/5/2016
Chapters 4 & 5
8
Summary of features
•
•
•
•
•
•
based on ANSI FDDI over copper
uses MLT-3 signaling
retains CSMA/CD
uses two pairs
uses Ethernet packet format
requires no changes to existing network
components, cabling, bridges
• need category 5 cabling
4/5/2016
Chapters 4 & 5
9
100Base-VG (Voice Grade)
• Designed by Hewlett Packard and AT&T
• allows users to assign priority to packets
(normal or high)
• increases the bandwidth from 10Mbps to
100Mbps
4/5/2016
Chapters 4 & 5
10
100Base-VG (Voice Grade)
• CSMA is not supported, instead, a
proprietary technique called quadrature
signaling and demand priority is used
• All four pairs are used to send the packet to
a hub
• If more than one packet arrives at the hub at
the same time, the highest priority packet is
serviced first
4/5/2016
Chapters 4 & 5
11
100Base-VG (Voice Grade)
•
•
•
•
•
Typically use VIDEO with high priority
Ethernet Frame – yes
CSMA/CD – no
Voice grade UTP – yes
Uses two-level NRZ output, 5 data bits
converted into 6 transmit bits
• Half-duplex
4/5/2016
Chapters 4 & 5
12
Summary of features
•
•
•
•
•
uses voice grade cable
supported by Microsoft, Apple, Novell, etc
signal is split over 4 pairs
data is half duplex, one direction at a time
handles time sensitive data like voice and
video
• CSMA/CD replaced with Demand Priority
Protocol
4/5/2016
Chapters 4 & 5
13
Summary of features
– IBM and HP have worked together to expand the
100Base-VG specification to include token ring
– This will support Cat3, type4 and Type5 cable
– It will not require any changes to existing wiring or to
bridges and routers
– The advantages of 100BaseVG-AnyLan over 100BaseT
are
• its topology is not so limiting
• traffic can be prioritized, giving better response to some users
who need it
• better suited to video and voice data
4/5/2016
Chapters 4 & 5
14
100BaseT
• This is an extension of the existing Ethernet
standard
• 100BaseTX uses two-pair Category 5
UTP/STP cabling
4/5/2016
Chapters 4 & 5
15
100BaseT
• 100BaseT4 uses four-pair Category 3, 4 or 5 UTP
cabling
• 100BaseFX uses two-strand fiber
• In order to achieve the high 100Mbps rate, the
collision timing associated with CSMA/CD is
reduced
• This means the total lengths of cabling from a
workstation to another via two hubs cannot exceed
205 meters
4/5/2016
Chapters 4 & 5
16
100BaseT
– If using fiber, a maximum distance of 405 meters from
workstation to hub is allowed
– 100BaseT devices are auto sensing, which means they
can run at either speed
– On startup, the card advertises their speed with a series
of Fast Link Pulses
– If a hub supports this, it will detect the FLP's, and then
negotiate with the card for the highest possible speed
– This can be over-ridden by network managers, who can
force the slower 10Mbps mode
4/5/2016
Chapters 4 & 5
17
Summary of features
–
–
–
–
supported by Sun, Synoptics and 3Com
uses CSMA/CD
uses Ethernet frame format
uses new signaling scheme using 3 voltage
levels
– 100Base-VG-AnyLAN
4/5/2016
Chapters 4 & 5
18
Gigabyte Ethernet
• 1000Base (802.3ab)
– Speed 1000Mb/sec (10 times 100BaseTX)
– Requires fiber or Cat 5e or Cat 6 cable
– 1000Base-LX, 1000Base-SX, 1000Base-CX
• 10000Base (802.3ae)
– Speed 10000Mb/sec
– 10G Ethernet (10GbE)
– No collisions, only used on fiber
4/5/2016
Chapters 4 & 5
19
Gigabyte Ethernet
• Labeling
– 10GBase-Transmission Technique
• E – Extended
• L – Long
• S – Short
4/5/2016
Chapters 4 & 5
20
Wireless
• IEEE created the standard in 1990
–
–
–
–
4/5/2016
802.11 2 mb / sec
802.11b 11mb /sec Wi-Fi
802.11a 108 mb /sec Wi-Fi5
802.11g 54 mb/sec
Chapters 4 & 5
21
Wireless
• Access point – transceiver to send & receive
signals
– Base station for the wireless network
– Links wireless and wired networks
• Range – 375 feet / 115 meters
• Supports over 100 users
• Uses CSMA/CA
4/5/2016
Chapters 4 & 5
22
Network Components
Network Segments
A specific length of cable
Devices can be attached to the cable
It has its own unique address
It has a limit on its length and the number of
devices which can be attached to it
4/5/2016
Chapters 4 & 5
23
Token Ring Cards
Look similar to Ethernet cards
Token Ring cards generally have a nine pin
DIN type connector to attach the card to the
network cable
4/5/2016
Chapters 4 & 5
24
Animated links
http://www.corning.com/opticalfiber/discovery_center/tutorials/fiber_101/index.asp
http://fcit.coedu.usf.edu/network/game/game.htm
http://www.rad.com/networks/1997/nettut/firewall.html
http://www.rad.com/networks/1997/nettut/start.html
http://www.rad.com/networks/1997/nettut/ethernet.html
4/5/2016
Chapters 4 & 5
25
Repeaters
A signal loses strength as it passes along a cable
A device called a repeater will boost the signal
Electrically amplifies the signal it receives and
rebroadcasts it.
4/5/2016
Chapters 4 & 5
26
Routers
• Routers were devised in order to separate
networks logically
– For instance, a TCP/IP router can segment the network
based on IP subnets
– Filtering at this level (on IP addresses) will take longer
than that of a bridge or switch which only looks at the
MAC layer
• Most routers can also perform bridging functions
• A major feature of routers, because they can filter
packets at a protocol level, is to act as a firewall
4/5/2016
Chapters 4 & 5
27
Bridges
 A device that allows you to segment a large
network into two smaller, more efficient
networks.
 Monitors the information traffic on both
sides of the network so that it can pass
packets of information to the correct
location
4/5/2016
Chapters 4 & 5
28
ETHERNET SWITCHES
• Ethernet switches increase network performance
by decreasing the amount of extraneous traffic on
individual network segments attached to the
switch
• They also filter packets a bit like a router does
• Core switches have faster throughputs than
workgroup switches
4/5/2016
Chapters 4 & 5
29
Virtual LAN
• VLAN
– Connecting users using logical groupings
– Accomplished through software and smart
switches
– Security and network isolation
– Similar users get connected together even if
they are in different locations
4/5/2016
Chapters 4 & 5
30
What is a Protocol?
A set of rules that governs the communications between
computers on a network
These rules include guidelines that regulate the following
characteristics of a network:
access method, allowed physical topologies,
types of cabling, and speed of data transfer
The most common protocols are:
Ethernet Local Talk Token Ring FDDI ATM
4/5/2016
Chapters 4 & 5
31
Internet Protocols
Networks (hardware) provide computers the
basic ability of transferring bits from one
computer to another
A set of rules which all of the network's
member agree on, that is a protocol
Communication Protocol is a standard
designed to specify how computers interact
and exchange messages
4/5/2016
Chapters 4 & 5
32
Internet Protocols
Protocol usually specifies:
message format
how to handle errors
For simplification engineers have decided to design a
set of protocols, each has different responsibilities
Instead of one protocol responsible for all forms of
communication. The set of protocols is called a
Protocol Suite covering all forms of
communication as needed
4/5/2016
Chapters 4 & 5
33
The OSI seven layers model
A layering model is the most common way to
divide a protocol suite to subparts and
describe them individually
Layering help us to have better understanding
of a protocol suite
Developed over 20 years ago – theoretical
model
4/5/2016
Chapters 4 & 5
34
4/5/2016
Layer
Responsibilities
1. Physical
Basic hardware components for
networks.
i.e. RS-232 specification
2. Data Link
Frame format, Transmitting frames over
the net.
3. Network
i.e. bit/byte stuffing, checksum
Address assignment, Packet's
forwarding methods
4. Transport
Transfer correctness
5. Session
Establishing a communication session,
Security, Authentication
i.e. passwords
6. Presentation
Computers represent data in different
ways (char, integer) thus the protocol
needs to translate the data to and from
the local node.
7. Application
Specifications for applications using the
network, how to send a request, how to
specify a filename over the net, how to
respond to a request etc..
Chapters 4 & 5
35
Internet protocol suite
PPP
Point-to-Point Protocol
A protocol for creating a TCP/IP connection
over both synchronous and asynchronous
systems
4/5/2016
Chapters 4 & 5
36
Internet protocol suite
PPP provides connections for host to network
or between two routers, It also has a
security mechanism
PPP is well known as a protocol for
connections over regular telephone lines
using modems on both ends. This protocol
is widely used for connecting personal
computers to the Internet
4/5/2016
Chapters 4 & 5
37
Internet protocol suite
SLIP
Serial Line Internet Protocol –
A point-to-point protocol to use over a serial
connection, a predecessor of PPP
There is also an advanced version of this protocol
known as CSLIP (compressed serial line internet
protocol) which reduces overhead on a SLIP
connection by sending just a header information,
increasing packet throughput.
4/5/2016
Chapters 4 & 5
38
Internet protocol suite
FTP
File Transfer Protocol –
FTP enables transferring of text and binary
files over TCP connection. FTP allows to
transfer files according to a strict
mechanism of ownership and access
restrictions. It is one of the most commonly
used protocols over the internet now days
4/5/2016
Chapters 4 & 5
39
Internet protocol suite
Telnet
Telnet is a terminal emulation protocol,
defined in RFC854, for use over a TCP
connection
Enables users to login to remote hosts and use
their resources from the local host
4/5/2016
Chapters 4 & 5
40
Internet protocol suite
SMTP
Simple Mail Transfer Protocol –
Dedicated for sending E-Mail messages
originated on a local host, over a TCP
connection, to a remote server
4/5/2016
Chapters 4 & 5
41
Internet protocol suite
SMTP defines a set of rules which allows two
programs to send and receive mail over the
network
The protocol defines the data structure that would be
delivered with information regarding the sender,
the recipient (or several recipients) and, of course,
the mail's body
4/5/2016
Chapters 4 & 5
42
Internet protocol suite
HTTP
Hyper Text Transport Protocol –
A protocol used to transfer hypertext pages across
the world wide web
SNMP
Simple Network Management Protocol
A simple protocol that defines messages related to
network management
Through the use of SNMP network devices such as
routers can be configured by any host on the LAN
4/5/2016
Chapters 4 & 5
43
Internet protocol suite
UDP
User Datagram Protocol A simple protocol that transfers datagram
(packets of data) to a remote computer
UDP doesn't guarantee that packets will be
received in the same order they were sent
UDP doesn't guarantee delivery at all
4/5/2016
Chapters 4 & 5
44
Internet protocol suite
TCP Transmission Control Protocol A protocol that enables a computer to send
data to a remote computer
Unlike UDP, TCP is reliable i.e. packets are
guaranteed to wind up at their target, at the
correct order
4/5/2016
Chapters 4 & 5
45
Internet protocol suite
IP
Internet Protocol The underline protocol for all the other protocols
in the TCP/IP protocol suite
IP defines the means to identify and reach a target
computer on the network
Computers in the IP world are identified by unique
numbers known as the IP address
4/5/2016
Chapters 4 & 5
46
Internet protocol suite
ARP Address Resolution Protocol In order to map an IP address into a hardware
address the computer uses the ARP protocol which
broadcasts a request message that contains an IP
address, to which the target computer replies with
both the original IP address and the hardware
address
NNTP
Network News Transport Protocol A protocol used to carry USENET posting
between News clients and USENET servers
4/5/2016
Chapters 4 & 5
47
4/5/2016
Chapters 4 & 5
48
Considerations When Choosing a
Topology
Future growth. With a star topology,
expanding a network is easily done by
adding another concentrator
Cable type. The most common cable in
schools is unshielded twisted pair, which is
most often used with star topologies
4/5/2016
Chapters 4 & 5
49
Considerations When Choosing a
Topology
Money. A linear bus network may be the least
expensive way to install a network; you do
not have to purchase concentrators
Length of cable needed. The linear bus
network uses shorter lengths of cable
4/5/2016
Chapters 4 & 5
50
Network Design Criteria
Ethernets and Fast Ethernets have design rules
that must be followed in order to function
correctly
Maximum number of nodes
Number of repeaters
Maximum segment distances are defined by the
electrical and mechanical design properties of
each type of Ethernet and Fast Ethernet
media
4/5/2016
Chapters 4 & 5
51
Network Design Criteria
A network using repeaters functions with the
timing constraints of Ethernet
Although electrical signals on the Ethernet
media travel near the speed of light, it still
takes a finite time for the signal to travel from
one end of a large Ethernet to another
The Ethernet standard assumes it will take
roughly 50 microseconds for a signal to reach
its destination
4/5/2016
Chapters 4 & 5
52
Network Design Criteria
Ethernet is subject to the "5-4-3" rule of repeater
placement:
the network can only have five segments connected;
it can only use four repeaters;
of the five segments, only three can have users
attached to them;
the other two must be inter-repeater links
4/5/2016
Chapters 4 & 5
53
5-4-3 Rule
One aspect of the Ethernet protocol requires
that a signal sent out on the network cable
reach every part of the network within a
specified length of time
4/5/2016
Chapters 4 & 5
54
5-4-3 Rule
Each concentrator or repeater that a signal
goes through adds a small amount of time
Between any two nodes on the network there
can only be a maximum of 5 segments,
connected through 4 repeaters/concentrators
In addition, only 3 of the segments may be
populated (trunk) segments if they are made
of coaxial cable
4/5/2016
Chapters 4 & 5
55
5-4-3 Rule
A populated segment is one which has one or more
nodes attached to it
This rule does not apply to other network protocols
or Ethernet networks where all fiber optic cabling
or a combination of a fiber backbone with UTP
cabling is used. If there is a combination of fiber
optic backbone and UTP cabling, the rule becomes
a 7-6-5 rule.
4/5/2016
Chapters 4 & 5
56
Network Design Criteria
If the design of the network violates these of
repeater and placement rules, then timing
guidelines will not be met and the sending
station will resend that packet
This can lead to lost packets and excessive
resent packets, which can slow network
performance and create trouble for
applications
4/5/2016
Chapters 4 & 5
57
Network Design Criteria
Fast Ethernet has modified repeater rules, since
the minimum packet size takes less time to
transmit than regular Ethernet. The length of
the network links allows for a fewer number of
repeaters
In Fast Ethernet networks, there are two
classes of repeaters
Class I repeaters have a latency of 0.7 microseconds or
less and are limited to one repeater per network
Class II repeaters have a latency of 0.46 microseconds or
less and are limited to two repeaters per network
4/5/2016
Chapters 4 & 5
58
Network Design Criteria
The following are the distance (diameter)
characteristics for these types of Fast
Ethernet repeater combinations:
Fast Ethernet
Copper
Fiber
No Repeaters
100m
412m
One Class I Repeater
200m
272m
One Class II Repeater
200 m
272m
Two Class II Repeaters
205m
228
4/5/2016
Chapters 4 & 5
59
Network Components
• Large networks are made by combining several
individual network segments together, using
appropriate devices like routers and/or bridges
• When network segments are combined into a
single large network, paths exist between the
individual network segments
– paths are called routes, and devices like routers and
bridges keep tables which define how to get to a
particular path.
4/5/2016
Chapters 4 & 5
60
Network Components
• When a packet arrives, the router/bridge looks at the
destination address of the packet, and determines which
network segment the packet is to be transmitted on in order
to get to its destination
• In the diagram, a packet arrives whose destination is
segment B. The bridge forwards this incoming packet from
segment A to the B segment.
4/5/2016
Chapters 4 & 5
61
Spanning Tree Algorithm
Switches and bridges generally learn about the segments they
are connected to
As packets arrive, they build up a table which lists the
network address used on the various network segments
Sometimes, a loop would be created which caused the wrong
packets to be sent on incorrect segments. These packets
could loop around the network, being forwarded on,
eventually arriving back, only to be forwarded on, etc
4/5/2016
Chapters 4 & 5
62
Spanning Tree Algorithm
This quickly floods the network.The spanning tree
algorithm is a software algorithm which defines
how switches and bridges can communicate and
avoid network loops
Packets are exchanged between bridges/switches,
and they establish a single path for reaching any
particular network segment
4/5/2016
Chapters 4 & 5
63
Spanning Tree Algorithm
This is a continuous process,so that if a
bridge/switch fails, the remaining devices can
reconfigure the routing tables to allow each
segment to be reached
Effective bridges/switches in use support this
protocol
4/5/2016
Chapters 4 & 5
64
Network
Standard
Transmission
Topology
Channel
Access
Method
Cable
Speed
Number of
Segments
10Base5
Baseband
Bus
CSMA/CD
Thick Coax
10Mbps
5
10Base2
Baseband
Bus
CSMA/CD
Thin Coax
10Mbps
2
10BaseT
Baseband
Bus / Star
CSMA/CD
UTP
10Mbps
1024
100BaseT
Baseband
Bus / Star
CSMA/CD
Varies
100Mbps
1024
Token Ring
Baseband
Star-wired
ring
Token Pass
STP / UTP
16 Mbps
264 or 568
100VG
AnyLan
Baseband
Star
Demand
Priority
UTP
100Mbps
Varies
4/5/2016
Chapters 4 & 5
65
Address Classes
4/5/2016
Chapters 4 & 5
66
Class A Networks (/8 Prefixes)
• Class A network address has an 8-bit networkprefix with the highest order bit set to 0 and a
seven-bit network number, followed by a 24-bit
host-number.
• Today Class A networks are referred to as "/8s"
(pronounced "slash eight" or just "eights")
– since they have an 8-bit network-prefix.
4/5/2016
Chapters 4 & 5
67
Class A Networks (/8 Prefixes)
• A maximum of 126 (27 -2) /8 networks can be
defined.
• The calculation requires that the 2 is
subtracted because the /8 network 0.0.0.0 is
reserved for use as the default route and the /8
network 127.0.0.0 (also written 127/8 or
127.0.0.0/8) is reserved for the "loopback"
function.
4/5/2016
Chapters 4 & 5
68
Class A Networks (/8 Prefixes)
• Each /8 supports a maximum of 16,777,214 (224 -2)
hosts per network.
• The host calculation requires that 2 is subtracted
because the all-0s ("this network") and all-1s
("broadcast") host-numbers may not be assigned to
individual hosts.
• Since the /8 address block contains 231 (2,147,483,648 )
individual addresses and the IPv4 address space
contains a maximum of 232 (4,294,967,296) addresses,
the /8 address space is 50% of the total IPv4 unicast
address space.
4/5/2016
Chapters 4 & 5
69
Class B Networks (/16 Prefixes)
• Each Class B network address has a 16-bit
network-prefix with the two highest order bits
set to 1-0 and a 14-bit network number,
followed by a 16-bit host-number.
4/5/2016
Chapters 4 & 5
70
Class B Networks (/16 Prefixes)
• Class B networks are now referred to as"/16s"
since they have a 16-bit network-prefix.
• A maximum of 16,384 (214 ) /16 networks can
be defined with up to 65,534 (216 -2) hosts per
network. Since the entire /16 address block
contains 230 (1,073,741,824) addresses, it
represents 25% of the total IPv4 unicast
address space.
4/5/2016
Chapters 4 & 5
71
Class C Networks (/24 Prefixes)
• Each Class C network address has a 24bit network-prefix with the three highest
order bits set to 1-1-0 and a 21-bit
network number, followed by an 8-bit
host-number. Class C networks are now
referred to as "/24s" since they have a 24bit network-prefix.
4/5/2016
Chapters 4 & 5
72
Class C Networks (/24 Prefixes)
• A maximum of 2,097,152 (221 ) /24
networks can be defined with up to 254
(28 -2) hosts per network. Since the entire
/24 address block contains 229
(536,870,912) addresses, it represents
12.5% (or 1/8th) of the total IPv4 unicast
address space.
4/5/2016
Chapters 4 & 5
73
Other Classes
• In addition to the three most popular
classes, there are two additional classes.
• Class D addresses have their leading
four-bits set to 1-1-1-0 and are used to
support IP Multicasting.
• Class E addresses have their leading fourbits set to 1-1-1-1 and are reserved for
experimental use.
4/5/2016
Chapters 4 & 5
74
4/5/2016
Chapters 4 & 5
75
Addressing
• Domain Name System (DNS)
–
–
–
–
4/5/2016
Part of the Transport Layer
Uses names to associate IP numbers
Used for major hosts
Yahoo.com, Excite.com, Go.com
Chapters 4 & 5
76
Private Network Numbers
• 10.X.X.X
/24
• 172.16.X.X thru 172.31.X.X /16
• 192.168.0.X thru 192.168.255.X
/8
– These networks are not to be used over the
Internet, but rather locally.
4/5/2016
Chapters 4 & 5
77
IPv6
Hdr
Opt Ext Hdr
Data Area
• Address size 128 bits (instead of 32)
• Entirely new header, uses two headers (the
second called an extension header)
• Datagram has a HOP limit
4/5/2016
Chapters 4 & 5
78
IPX/SPX
• Internetwork Packet exchange / Sequenced Packet
Exchange
– NCP Netware Core Protocol sends messages back and forth
– SAP Service advertising protocol hosts are available
– RIP Routing information protocol
4/5/2016
Chapters 4 & 5
79
Application
Application Programs and
Presentation Utilities
Session
4/5/2016
Transport
SPX
Network
IPX NCP SAP RIP
Data Link
Same as OSI
Physical
Same as OSI
Chapters 4 & 5
80
NetBeui
• Microsoft protocol
– Single small networks
– Packet saturated due to address broadcasts
4/5/2016
Chapters 4 & 5
81
Application
Session
Application Programs and Utilities
SMB
NetBIOS
Transport
NetBEUI
Presentation
Network
Data Link
Same as OSI
Physical
Same as OSI
4/5/2016
Chapters 4 & 5
82