Teledyne LeCroy IBTrainer - IBTrainer Users Manual - Manual (Page 28)

Overview of the IBTrainer Testing Capabilities of the IBTrainer
28
CATC IBTrainer InfiniBand Exerciser, August 2002
The receive memory of the IBTrainer consists of a single block of 2
Mbytes. By selecting a virtual lane resource you decide which path the
data stream is to use. Refer to “Receiving Packets” on page 31 for more
information.
Transmit Credits You can set a behavior for each packet to either ignore credits or to
behave according to the specification.
Detailed organization of the IBTrainer credit system is as follows:
• The FCCL calculation is based on a 12-bit Adjusted Blocks Received
(ABR) counter maintained for each virtual lane at the receiver. The
ABR counter is set to zero when the link initializes. This is in
accordance with the specification. Upon receipt of each flow control
packet, the ABR sets the value of the FCTBS (Flow Control Total
Blocks Sent) field.
• Upon receipt of each data packet, the ABR is incremented by the
number of blocks received, modulo 4096. The ABR does not get
incremented due to received packets that have been discarded due to
the lack of receive capacity in the receiver. You can adjust this
capacity for the IBTrainer in the data sink mode.
• Upon transmission of a flow control packet, the FCCL is set to one of
the following:
– If the current buffer state of the receiver permits reception of 2048
or more blocks from all combinations of valid InfiniBand packets
without discarding them, the FCCL is set to ABR plus 2048 modulo
4096.
– Otherwise the FCCL is set to ABR plus the number of blocks the
receiver is capable of receiving from all combinations of valid
InfiniBand packets without discarding these, modulo 4096.
Addressing
Source addresses are generated automatically depending on the address
supplied to the IBTrainer by the subnet manager. Source addresses can
be overwritten. This way the IBTrainer can emulate a switch or a router.
The IBTrainer is capable of generating all types of InfiniBand packets as
allowed by the specification. This includes any MAD packets, any regular
InfiniBand packets, Raw or RawIPv6 packets. Refer to section 5.2 in the
InfiniBand specification (data packet format) for more details.
The destination address for the packets is always defined by the user.