ATM Adaptation Layer 0 (AAL-0)

ATM Adaptation Layer 0 (AAL-0) supports raw cell transport. It has an SAR- PDU header or trailer.

ATM Adaptation Layer 1 (AAL-1)

ATM Adaptation Layer 1 (AAL-1) supports constant bit rate data such as voice, video, or other continuous user data. AAL-1 transfers data at a fixed speed. AAL- 1 contains a 47-byte payload and a 1-byte header.

ATM Adaptation Layer 3/4 (AAL-3/4)

ATM Adaptation Layer 3/4 (AAL-3/4) supports variable bit rate data with connection oriented (type 3) or connectionless (type 4) data services. AAL-3/4 supports two modes of operation - Message Mode which is used for framed data, and Stream Mode which is used for low-speed continuous data. AAL-3/4 contains a 44-byte payload with a 2-byte header and a 2-byte trailer.

ATM Adaptation Layer 5 (AAL-5)

ATM Adaptation Layer 5 (AAL-5) supports variable bit rate data with connection oriented or connectionless data services. AAL-5 was designed as a simple protocol that assumes some of the functions such as error detection, timing and other overhead information is accomplished by the next level protocol. AAL-5 contains a 48-byte payload with control information in the normal ATM 5-byte header.

ATM Cell

An ATM Cell is a 53-byte protocol data unit made up of a 5-byte cell header and a 48-byte payload (information field).

ATM Layer

The layer in ATM that switches cells to their correct destinations within the network.

ATMProbe

See probe.

Auto-Negotiation

The process by which a probe determines the network speed and automatically sets its own configuration to match that speed.

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Agilent Technologies J3919A ATM Adaptation Layer 0 AAL-0, ATM Adaptation Layer 1 AAL-1, ATM Adaptation Layer 3/4 AAL-3/4