PPP over ATM
From Encyclopedia of Cybersecurity
PPP over ATM (PPPoA)
PPP over ATM (PPPoA) is a network protocol used to establish a point-to-point connection over Asynchronous Transfer Mode (ATM) networks. It enables the encapsulation of Point-to-Point Protocol (PPP) frames within ATM cells, allowing the transmission of PPP packets over ATM-based networks, such as DSL and broadband connections.
Operation
PPPoA operates by establishing a session between a client device and an Internet Service Provider (ISP) through an ATM network. The PPPoA session involves the following steps:
- ATM Virtual Circuit Setup: The client establishes a virtual circuit (VC) connection with the ISP's network access server (NAS) using ATM signaling protocols, such as ATM Forum UNI (User-to-Network Interface) signaling or ATMARP (ATM Address Resolution Protocol).
- PPP Session Establishment: Once the virtual circuit is established, the client initiates a PPP session with the NAS by sending PPP control packets encapsulated within ATM cells.
- Authentication: The client and NAS authenticate each other using various authentication methods, such as Password Authentication Protocol (PAP) or Challenge Handshake Authentication Protocol (CHAP).
- Data Transfer: Once the PPP session is established and authenticated, PPP frames encapsulated within ATM cells are exchanged between the client and NAS, allowing for the transmission of PPP packets over the ATM network.
Features
PPPoA provides several features that make it suitable for broadband Internet access:
- Broadband Access: PPPoA is commonly used by ISPs to provide broadband Internet access to residential and small business users over DSL and other ATM-based connections.
- Efficiency: PPPoA encapsulates PPP frames within fixed-size ATM cells, providing efficient utilization of network bandwidth and reducing overhead.
- Dynamic IP Address Assignment: PPPoA allows ISPs to dynamically assign IP addresses to client devices using PPP's Network Control Protocol (NCP), simplifying IP address management.
Advantages
- Broadband Compatibility: PPPoA is widely supported by ISPs and networking equipment, making it compatible with various broadband technologies based on ATM.
- Efficiency: PPPoA efficiently utilizes network bandwidth by encapsulating PPP frames within fixed-size ATM cells.
Disadvantages
- Complexity: Setting up PPPoA connections may require additional configuration compared to other broadband connection methods, as it involves both ATM and PPP protocols.
- Overhead: PPPoA introduces additional overhead due to the encapsulation of PPP frames within ATM cells, which can reduce network throughput.
See Also
- Point-to-Point Protocol (PPP)
- Asynchronous Transfer Mode (ATM)
- Digital Subscriber Line (DSL)
- Broadband Internet
