Fichier PDF

Partagez, hébergez et archivez facilement vos documents au format PDF

Partager un fichier Mes fichiers Boite à outils PDF Recherche Aide Contact



devoir Anglais final .pdf



Nom original: devoir_Anglais_final.pdf
Titre: 2010 / 2011
Auteur: Un utilisateur satisfait de Microsoft Office

Ce document au format PDF 1.5 a été généré par Microsoft® Word 2010, et a été envoyé sur fichier-pdf.fr le 25/11/2011 à 14:12, depuis l'adresse IP 147.215.x.x. La présente page de téléchargement du fichier a été vue 1101 fois.
Taille du document: 498 Ko (11 pages).
Confidentialité: fichier public




Télécharger le fichier (PDF)









Aperçu du document


2011 / 2012

DA SILVA Xavier

Point-to-Point Protocol

ESIEE ENGINEERING 2011/2012

Page 1/11

Introduction

PPP, or Point to Point Protocol, is a protocol for exchanging data over one point to
another. Its main advantage is that once the link between the two points is established,
you can establish multiple connections of various protocols simultaneously. It is,
therefore, a major asset in the field of the Internet.
On the first hand, I will present the primary use and operating properly, and then
secondly, I will explain the format of the PPP frames, and finally, I would like to
speak about different protocols

ESIEE ENGINEERING 2011/2012

Page 2/11

Table of contents

Introduction .......................................................................... Erreur ! Signet non défini.

Summary .............................................................................. Erreur ! Signet non défini.

I.

Primary use .................................................................... Erreur ! Signet non défini.
1. PPP elements ............................................................. Erreur ! Signet non défini.
2. Connection establishment scheme ............................. Erreur ! Signet non défini.

II. Frames description ........................................................ Erreur ! Signet non défini.

III. diverse protocols ............................................................ Erreur ! Signet non défini.
1. LCP protocol ......................................................................................................... 9
2. Authentification protocol ........................................... Erreur ! Signet non défini.
3. NCP protocol ........................................................................................................ 9
4. PPPoE protocol ................................................................................................... 10

Conclusion .................................................................................................................... 11

ESIEE ENGINEERING 2011/2012

Page 3/11

I. Primary use

1. PPP elements

PPP is widely used in the Internet. We can establish a connection between two
points. This protocol is at the link layer of the OSI model.
PPP is based on three elements:
• The encapsulation of datagram to carry multiple network protocols
simultaneously in the same frame.
• A control protocol for liaison with LCP (Link Control Protocol) that establishes,
configures, and tests the data link layer.
• Control of the network layer with NCP (Network Control Protocol).

2. Connection establishment scheme

- Negotiation of the use of the link (Establish)

Uses the PPP LCP (Link Control Protocol) to negotiate link parameters such as
maximum size of the PPP frame, the use of Multilink and the use of a specific PPP
authentication protocol.

- Authentication of the remote access computer (Authenticate)
The remote access client and remote access server exchange messages according to the
negotiated authentication protocol. If EAP is used, the client and server negotiate a
specific EAP method, known as EAP type, then exchange the messages of this type
EAP.

ESIEE ENGINEERING 2011/2012

Page 4/11

- Negotiation of the use of network protocols (Network)
This process involves the use of a set of protocols NCP (Network Control Protocol) to
configure the network protocols used by the remote access client. For example, the
NCP protocol to TCP / IP IPCP (Internet Protocol Control Protocol). If the remote
access client is configured to use TCP / IP, IPCP is used to assign an IP address to the
client and to configure the client with the IP addresses of DNS and WINS servers.

- Closing of the link (Terminate)
PPP LCP uses to inform the network layer protocol that the connection will be cut.

ESIEE ENGINEERING 2011/2012

Page 5/11

The following diagram reflects the stages of a Connection establishment:

+------+

+-----------+

| Dead | UP

| Establish |

|

|---->|

+------+

+--------------+
OPEN

| Authenticate | SUCCESS

|-------->|

+-----------+

^

|

| FAIL

|

|----+

+--------------+

|

|

|

|

|

+<------------+

+---------+

|

|

|

|

|

|

|

|

|

|

|

|

|

| DOWN

FAIL

+-----------+

|

SHUT

+----------+

+-------| Terminate |<---+<-----------|
|

|

+-----------+

ESIEE ENGINEERING 2011/2012

|

|

Network |<--+
|

+----------+

Page 6/11

II. Frames description

Adresse

Command

8 bits

8 bits

8 bits

(01111110b)

(11111111b)

(00000011b)

Protocol

Data FCS

8 ou 16 bits



16/32 bits

End fanion

8 bits
(01111110b)

The flag start and end
Like the LAP-B protocol, limit of the frames are set by a flag, and the binary sequence
is 01111110 (0x7E).

Address field
In standard mode, this field contains the broadcast address to all receivers, 11111111
(0xFF) .. This simplifies the dissemination of messages to a set of machines, because it
has sent the message to a single address.

The Command field
The standard sequence 00000011 (0x03) indicates that the frame is an unnumbered
information frame (UI, Un-numbered Information). It is possible to use a numbered
mode for reliability. 00000011 value also corresponds to a P / F bit set to 0.

The Protocol field
This field does not come from HDLC to PPP but it’s clean. It’s coded by 1 or 2 bytes,
it indicates what protocol transmits data in the Information field. This is the principle
of encapsulation, which allows a network layer protocol to transfer data through the
Information field of a PPP frame standard. In any protocol is associated with a
number:

ESIEE ENGINEERING 2011/2012

Page 7/11

• From 0000 to 3FFF: network layer protocols (NPs)
0021: Internet Protocol version 4 (IPv4)
0029: Appletalk
002b Novell IPX
• From 4000 to 7FFF: Network layer protocols with no associated NCP
• From 8000 to BFFF: control protocols associated with the first NPs (NCPs)
8021: Internet Protocol Control Protocol (IPCP)
8029: Appletalk Control Protocol
802b Novell IPX Control Protocol
• From C000 to FFFF: protocols for controlling the data link layer
C021: Link Control Protocol (LCP)
C023: Password Authentication Protocol (PAP)
C025: Link Quality Report (LQR)

Error detection field (Frame Check Sequence)
The Frame Check Sequence detect whether an error occurred. The calculations is
performed on all the fields Address, Control, Protocol and Information before adding
the transparency bits and start or stop bits. Upon reception, it removes the transparency
bits or bytes and bits start or stop before checking the absence of error.

ESIEE ENGINEERING 2011/2012

Page 8/11

III.

Diverse protocols

1. LCP protocol

The LCP or Link Control Protocol, is used to define and configure the PPP frames.
These frames define how to encapsulate the data for transmission over a WAN.

2. Authentification protocol

Authentication protocols come out when the quality of the connection was
made and before the negotiation of the network layer.

3. NCP protocol

The NCP or Network Control Protocol, is used to establish and configure the various
parameters of network protocols for TCP / IP, IPX and AppleTalk. There are three
NCP protocols used with a PPP connection:
- ICPC protocol, or Internet Protocol Control Protocol, used to configure TCP / IP on
the remote access client. It can provide an IP address, IP address of the DNS and
WINS servers in remote access client.
- The IPXCP or Internetwork Packet Exchange Control Protocol, is used to configure
the IPX protocol on the remote access client. It can provide the IPX network and node
numbers in the remote access client.
- The protocol ATCP, or AppleTalk Control Protocol, is used to configure the
AppleTalk protocol on the remote access client. It can provide the address to
AppleTalk remote access client.

ESIEE ENGINEERING 2011/2012

Page 9/11

Be aware that the PPP Settings dialog box as the possibility to separate channels
according to their priority, whether high or low, with the option Negotiate multi-link
for single link connections.

4. PPPoE protocol

PPPoE, or Point to Point Protocol over Ethernet, provides access to high speed
data networks via a modem and authenticated manner. By combining the PPPoE and
Ethernet, it is possible to create a separate connection to a remote server for each user.

ESIEE ENGINEERING 2011/2012

Page 10/11

Conclusion

We have seen that PPP is a protocol widely used in the Internet because it
allows, by the principle of encapsulation, to send in a single frame multiple protocols
and their data. PPP allows us to establish a connection between two points. Another
advantage of PPP is the use of the LCP, which gives it good portability.

ESIEE ENGINEERING 2011/2012

Page 11/11


Documents similaires


Fichier PDF devoir anglais final
Fichier PDF project part 2 question c
Fichier PDF electricity dictionary
Fichier PDF ieee802lansformattram
Fichier PDF b net 155 bootstrap1
Fichier PDF reseau 2 2


Sur le même sujet..