PPP means Point to Point Protocol. It is a communication procedure which is utilized for the creation of a direct channel between two points of the networks. PPP is mainly used in WAN and it may offer authentication and encryption and data compression that is required in the transmission of data.
What is Point-to-Point Protocol (PPP)?
PPP stands for Point-to-Point Protocol. PPP is Windows default Remote Access Service (RAS) protocol and is Data Link Layer (DLL) protocol used to encapsulate higher network layer protocols to pass through synchronous and asynchronous lines of communication. Initially created as an encapsulation protocol to carry numerous layer of network traffic over point-to-point connections. In addition, PPP settled various measures including asynchronous and bit-oriented synchronous encapsulation, multiplexing of network protocols, negotiation of sessions, and negotiation of data-compression. PPP also supports non TCP / IP protocols, such as IPX / SPX and DECnet. A prior standard known as Serial Link Internet Protocol (SLIP) has been largely replace by it.
What is the PPP Authentication Protocol?
PPP supports two main authentication protocols:PPP supports two main authentication protocols:
- Password Authentication Protocol (PAP): A basic authentication scheme where the user’s identity information such as the user name and password are transmitted in the plain format. Its disadvantage is that it is less secure because of the simplicity.
- Challenge Handshake Authentication Protocol (CHAP): CHAP is more secure as it periodically alert the identity of the remote client by using a three way hand shake method. The password is encrypted, thus it is much more secure than plaintext PAP.
Which Protocol is Replaced by PPP?
PPP took the place of the Serial Line Internet Protocol (SLIP). SLIP was one of the older protocols that was used for establishing connections for serial means to provide P-P communication contacts but it had some issues such as, it did not support features like error detection and link multiplexing. PPP has certain advancements over the conventional protocols with respect to error detection, multiplexing and authentication and therefore is more appropriate for use on the modern internet connections.
Services Provided by PPP
PPP offers several essential services, including:PPP offers several essential services, including:
- Data Encapsulation: It enshrines network layer protocols such as IP and others for transmission over serial link.
- Link Control Protocol (LCP): It is employed to set up, initial and finalize the data link connection.
- Network Control Protocols (NCP): PPP has provisions for supporting many NCPs for the configuration of the network-layer protocols such as IP, IPX, and AppleTalk.
- Authentication: Offers both PAP and CHAP for the purpose of authentication.
- Error Detection: It also has methods of maintaining integrity of the data through error checking techniques.
History of Point-to-Point Protocol (PPP)
PPP returns to late 1980s, when true standard for sequential IP executions was SLIP. RFC 1134, distributed in 1989, was principal formal IETF report identified with PPP. This RFC isn’t just standard yet proposal for what could be characterized as primary PPP standard, RFC 1171, in 1990. This early report has been re-examined numerous times and included few different records characterizing different protocols that contain entire PPP suite. Instead of trying to create PPP from scratch, IETF built PPP on basis of ISO High-Level Data Link Control (HDLC) protocol, which was initially developed by IBM. Developers of PPP adopted its framing mechanism from HDLC protocol and component of its general operation.
Features of PPP
- Packet Framing - Network layer data packet formulation within data link block.
- Multi-Protocol - Yield information from any NCP network layer upwards at same time as demultiplex.
- Bit Transparency - Should carry certain bit pattern in field of data.
- Error Detection - No modification.
Components of PPP
It uses three components to allow PPP to transmit data over serial point-to – point link. Each part has its own autonomous role and entails use of other two complete its tasks.
These three components are :
- High-Level Data-Link Control (HDLC) protocol - HDLC is method used to frame data over PPP links. On account of PPP, the standard version of OSI is used instead of proprietary version of Cisco. This standardization assists in ensuring that different vendors can properly communicate PPP executions.
- Link Control Protocol (LCP) - It is liable for formulating, configuring, testing, sustaining and terminating transmission links. Additionally, two endpoints of connections impart negotiation for setting up of alternatives and use of features.
- Network Control Protocols (NCPs) - NCP frames are used to communicate and customize protocols on Network layer that can be used over PPP session. There is one NCP for every higher-layer protocol that is upheld by PPP. NCPs enable PPP to work over analogous connection in consonance with many Network layer protocols.
Working of PPP
PPP jointly uses these three components to enable communication. There are four main steps to establish, maintain and terminate PPP session:
- Step-1: Initial step of setting up PPP session between devices includes both sending LCP link-establishment frame for configuration and testing purposes. Such frames also characterize which alternatives, for instance compression, authentication, and multilink, given PPP host chooses. If authentication is established and needed it will take place during this step.
- Step-2: It uses LCP frames to test link ‘s nature. Assembled data can be used to evaluate if links is appropriate for dealing different protocols on upper layer.
- Step-3: NCP frames are sent over link to determine which network layer protocols need configuration. For instance, connection to use IP, IPX, AppleTalk and so on can need to be optimized.
- Step-4: In this step, when ending PPP session, LCP link-termination frames are used to cut connection. Third category of LCP frame (Link-Maintenance) is often used for leveraging and troubleshooting PPP links.
Advantages of PPP
- Supports Multiple Protocols: PPP can support various network layer protocol hence it is well suitable for any specific network.
- Error Detection: Such features as built-in error detection make it possible to have reliable data transmission.
- Authentication: These support features secure connection establishment with authentication protocols.
- Compression: PPP much backs data compression with the intention of improving the transmission rates.
Disadvantages of PPP
- Overhead: PPP brings about overhead since it involves packaging and managing different protocols.
- Limited to Point-to-Point: As it is clear form the name, PPP is only able to support direct point to point connections, and hence it is not very useful in large networks.
- Complex Configuration: PPP also requires configuration and management of the links which may make the configuration and management of PPP a bit tough compared to the other protocols like Ethernet.
Conclusion
To date, the PPP or Point-to-Point Protocol continues to be an essential protocol of communication in networking more so where WANs and dial-up connections are involved. It is good in supporting authentication, error detection, & encapsulation & therefore can be recommended for use in point to point data transfer. However, when designing networks, it must be noted that it has the disadvantage of scalability and high overhead.