Download RDMA Aware Networks Programming User Manual

Rev 1.7
Term
Description
LID (Local IDentifier)
A 16 bit address assigned to end nodes by the subnet manager.
Each LID is unique within its subnet.
LLE (Low Latency
Ethernet)
RDMA service over CEE (Converged Enhanced Ethernet) allowing IB transport
over Ethernet.
NA (Network Adapter)
A device which terminates a link, and executes transport level functions.
MGID (Multicast Group
ID)
IB multicast groups, identified by MGIDs, are managed by the SM. The SM associates a MLID with each MGID and explicitly programs the IB switches in the fabric
to ensure that the packets are received by all the ports that joined the multicast
group.
MR (Memory Region)
A contiguous set of memory buffers which have already been registered with
access permissions. These buffers need to be registered in order for the network
adapter to make use of them. During registration an L_Key and R_Key are created
and associated with the created memory region
MTU (Maximum
Transfer Unit)
The maximum size of a packet payload (not including headers) that can be sent /
received from a port
MW (Memory Window)
An allocated resource that enables remote access after being bound to a specified
area within an existing Memory Registration. Each Memory Window has an associated Window Handle, set of access privileges, and current R_Key.
Outstanding Work Request
WR which was posted to a work queue and its completion was not polled
pkey (Partition key)
The pkey identifies a partition that the port belongs to. A pkey is roughly analogous
to a VLAN ID in ethernet networking. It is used to point to an entry within the
port’s partition key (pkey) table. Each port is assigned at least one pkey by the subnet manager (SM).
PD (Protection Domain)
Object whose components can interact with only each other.
AHs interact with QPs, and MRs interact with WQs.
QP (Queue Pair)
The pair (send queue and receive queue) of independent WQs packed together in
one object for the purpose of transferring data between nodes of a network.
Posts are used to initiate the sending or receiving of data.
There are three types of QP: UD Unreliable Datagram, Unreliable Connection, and
Reliable Connection.
RC (Reliable Connection)
A QP Transport service type based on a connection oriented protocol.
A QP (Queue pair) is associated with another single QP. The messages are sent in a
reliable way (in terms of the correctness and order of the information.)
RDMA (Remote Direct
Memory Access)
Accessing memory in a remote side without involvement of the remote CPU
RDMA_CM (Remote
Direct Memory Access
Communication
Manager)
API used to setup reliable, connected and unreliable datagram data transfers. It provides an RDMA transport neutral interface for establishing connections. The API is
based on sockets, but adapted for queue pair (QP) based semantics: communication
must be over a specific RDMA device, and data transfers are message based.
Requestor
The side of the connection that will initiate a data transfer (by posting a send
request)
Responder
The side of the connection that will respond to commands from the requestor which
may include a request to write to the responder memory or read from the responder
memory and finally a command requesting the responder to receive a message.
rkey
A number that is received upon registration of MR is used to enforce permissions
on incoming RDMA operations
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