10. What is BYNET ?

BYNET

The

BYNET handles the internal communication of the Teradata

Database. All communication between PEs and AMPs is done via the

BYNET.

When the PE dispatches the steps for the AMPs to perform, they are

dispatched onto the BYNET. The messages are routed to the appropriate

AMP(s) where results sets and status information are generated. This

response information is also routed back to the requesting PE via the

BYNET.

Depending on the nature of the dispatch request, the communication

between nodes may be a:

·

Broadcast—message is routed to all nodes in the system.

·

Point-to-point—message is routed to one specific node in the

system.

Once the message is on a participating node, PDE directs the message to

the appropriate AMPs on that node. All AMPs receive a broadcast

message. With a point-to-point or multicast (multiple AMPs) message, the

message is directed only to the appropriate AMP(s) on that node.

So, while a Teradata system does do multicast messaging, the BYNET

hardware alone cannot do it - the BYNET can only do point-to-point and

broadcast between nodes.

The BYNET has several unique features:

Fault tolerant:

each network has multiple connection paths. If the BYNET

detects an unusable path in either network, it will automatically reconfigure

that network so all messages avoid the unusable path. Additionally, in the

rare case that BYNET 0 cannot be reconfigured, hardware on BYNET 0 is

disabled and messages are re-routed to BYNET 1, and vice versa.

Load balanced:

traffic is automatically and dynamically distributed

between both BYNETs.

Scalable:

as you add nodes to the system, overall network bandwidth

scales linearly - meaning an increase in system size without loss of

performance.

High Performance:

an MPP system has two BYNET networks. Because

both networks are active, the system benefits from the full aggregate

bandwidth.

The technology of the BYNET is what makes the Teradata parallelism
possible.