Type of Service
Currently, five ATM Forum-defined service categories exist (see Table 1). The basic differences among these service categories are described in the following sub-sections. These service categories provide a method to relate traffic characteristics and QoS requirements to network behaviour. The service categories are characterised as being real-time or non-real-time. CBR and rt-VBR are the real-time service categories. The remaining three service categories (nrt-VBR, UBR and ABR) are considered non-real-time service categories.
ATM Forum Traffic Management 4.0 ATM Service Category | ITU-T I.371 ATM Transfer Capability | Typical Use |
---|---|---|
Constant Bit Rate (CBR) | Deterministic Bit Rate (DBR) | Real-time, QoS guarantees |
Real-Time Variable Bit Rate (rt-VBR) | (for further study) | Statistical mux, real time |
Non-Real-Time Variable Bit Rate (nrt-VBR) | Statistical Bit Rate (SBR) | Statistical mux |
Available Bit Rate (ABR) | Available Bit Rate (ABR) | Resource exploitations, feedback control |
Unspecified Bit Rate (UBR) | (No equivalent) | Best effort, no guarantees |
(No equivalent) | ATM Block Transfer (ABT) | Burst level feedback control |
Read more about this topic: Traffic Contract
Famous quotes containing the words type of, type and/or service:
“The Republican form of government is the highest form of government; but because of this it requires the highest type of human naturea type nowhere at present existing.”
—Herbert Spencer (18201903)
“Music, in performance, is a type of sculpture. The air in the performance is sculpted into something.”
—Frank Zappa (19401994)
“This was a great point gained; the archdeacon would certainly not come to morning service at Westminster Abbey, even though he were in London; and here the warden could rest quietly, and, when the time came, duly say his prayers.”
—Anthony Trollope (18151882)