The InfiniBand architecture defined by IBTA includes Quality of Service and Congestion Control features that are tailored perfectly to the needs of Data Center Networks. Through use of features available today in InfiniBand Architecture based hardware devices, InfiniBand can address QoS requirements in Data Center applications in an efficient and simpler way, better than any other interconnect technology available today.
When starting to play around InfiniBand QoS, you will need to understand two basic concepts.
Service levels (SLs) and Virtual Lanes (VLs).
Basic Concepts
Service Level (SL)
A field in the Local Routing Header (LRH) which defines the requested QoS. It permits a packet to operate at one of 16 SLs. Assignment of SLs is a function of each node’s communication manager (CM) and its negotiation with the SM.
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Virtual Lane (VL)
Virtual lanes provide a mechanism for creating multiple channels within a single physical link.
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# QoS default options qos_max_vls 4 qos_high_limit 255 qos_vlarb_high 1:192, 2:128, 3:64 qos_vlarb_low 0:64 qos_sl2vl 0,1,2,3 |