Intel Xeon Processor Multiprocessor Platform Design Guide

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Introduction
1.2 Conventions and Terminology
This section defines conventions and terminology that will be used throughout this document.
Table 1-2. Platform Conventions and Terminology (Sheet 1 of 3)
Convention/
Terminology
Definition
4-way Used to specify a system configuration using four processors.
Aggressor
A network that transmits a coupled signal to another network is called the aggressor
network.
AGTL+
The processor system bus uses a bus technology called AGTL+, or Assisted Gunning
Transceiver Logic. AGTL+ buffers are open-drain and require pull-up resistors that provide
the high logic level and termination. AGTL+ output buffers differ from GTL+ buffers with the
addition of an active pMOS pull-up transistor to “assist” the pull-up resistors during the first
clock of a low-to-high voltage transition.
Bus Agent
A component or group of components that, when combined, represent a single load on the
AGTL+ bus.
Corner
Describes how a component performs when all parameters that could impact performance
are adjusted simultaneously to have the best or worst impact on performance. Examples of
these parameters include variations in manufacturing process, operating temperature, and
operating voltage. Performance of an electronic component may change as a result of
(including, but not limited to): clock to output time, output driver edge rate, output drive
current, and input drive current. The “slow” corner means a component is operating at its
slowest, weakest drive strength performance. The “fast” corner means a component is
operating at its fastest, strongest drive strength performance. Operation or simulation of a
component at its slow corner and fast corner is expected to bound the extremes between
slowest, weakest performance and fastest, strongest performance.
Crosstalk
The reception on a victim network of a signal imposed by aggressor network(s) through
inductive and capacitive coupling between the networks.
Backward Crosstalk – coupling that creates a signal in a victim network that travels in the
opposite direction as the aggressor’s signal.
Forward Crosstalk – coupling that creates a signal in a victim network that travels in the
same direction as the aggressor’s signal.
Even Mode Crosstalk – coupling from single or multiple aggressors when all the
aggressors switch in the same direction that the victim is switching.
Odd Mode Crosstalk – coupling from single or multiple aggressors when all the aggressors
switch in the opposite direction that the victim is switching.