Used to select a specific packet OpCode (as found in BTH) when sampling optional quantities that are op code specific. If OpCode is 0xFF, all OpCodes are sampled as one otherwise only one OpCode can be sampled at a time, although multiple quantities can be sampled for the same OpCode. The possible OpCode are defined as follows: 0x0 : RC SEND First, 0x1 : RC SEND Middle, 0x2 : RC SEND Last, 0x3 : RC SEND Last with Immediate, 0x4 : RC SEND Only, 0x5 : RC SEND Only with Immediate, 0x6 : RC RDMA Write First, 0x7 : RC RDMA Write Middle, 0x8 : RC RDMA Write Last, 0x9 : RC RDMA Write Last with Immediate, 0xA : RC RDMA Write Only, 0xB : RC RDMA Write Only with Immediate, 0xC : RC RDMA Read Request, 0xD : RC RDMA Read Response First, 0xE : RC RDMA Read Response Middle, 0xF : RC RDMA Read Response Last, 0x10 : RC RDMA Read Response Only, 0x11 : RC RDMA Acknowledge, 0x12 : RC RDMA Atomic Acknowledge, 0x13 : RC RDMA CmpSwap, 0x14 : RC RDMA FetchAdd, 0x15 - 0x1F : RC Reserved, 0x20 : UC Send First, 0x21 : UC Send Middle, 0x22 : UC Send Last, Yang/Tsang Internet Draft- Expires May 2002 8 Infiniband Performance Management MIB Nov 2001 0x23 : UC Send Last with Immediate, 0x24 : UC Send Only, 0x25 : UC Send Only with Immediate, 0x26 : UC RDMA Write First, 0x27 : UC RDMA Write Middle, 0x28 : UC RDMA Write Last, 0x29 : UC RDMA Write Last with Immediate, 0x2A : UC RDMA Write Only, 0x2B : UC RDMA Write Only with Immediate, 0x2C - 0x3F : UC Reserved 0x40 : RD Send First, 0x41 : RD Send Middle, 0x42 : RD Send Last, 0x43 : RD Send Last with Immediate, 0x44 : RD Send Only, 0x45 : RD Send Only with Immediate, 0x46 : RD RDMA Write First, 0x47 : RD RDMA Write Middle, 0x48 : RD RDMA Write Last, 0x49 : RD RDMA Write Last with Immediate, 0x4A : RD RDMA Write Only, 0x4B : RD RDMA Write Only with Immediate, 0x4C : RD RDMA Read Request, 0x4D : RD RDMA Read Response First, 0x4E : RD RDMA Read Response Middle, 0x4F : RD RDMA Read Response Last, 0x50 : RD RDMA Read Only, 0x51 : RD Acknowledge, 0x52 : RD Atomic Acknowledge, 0x53 : RD CmpSwap, 0x54 : RD FetchAdd, 0x55 - 0x5F : RD Reserved, 0x64 : UD Send Only, 0x65 : UD Send Only with Immediate, 0x66 - 0x7F : UD Reserved, 0x80 - 0xBF : Reserved, 0xC0 - 0xEF : Manufacture Specific Opcodes.