Physical Chaining - IXIA Optixia XM12 Hardware And Reference Manual

Theory of Operation: General
2
Chassis
2-6
The use of both Reset and Phase Lock allow the establishment and maintenance
of a fixed time reference between two or more chassis and the ports supported by
the chassis.
In test setups where chassis and ports are physically close together, a sync cable
is used to connect chassis in a 'chassis chain' for synchronization operation.
In widely distributed applications, such as monitoring traffic characteristics over
a WAN, clock reference and/or reset signals cannot be transmitted between
chassis over a physical connection because of unknown delay characteristics. An
alternative means is required to satisfy these requirements.
Ixia has facilities that allow for the synchronization of independent Ixia chassis
located anywhere in the world by replacing the existing inter-chassis sync cables
with a widely available frequency and time standard supplied from an external
source. This source provides a reference time used to obtain accurate latency and
other measurements in a live global network. When geographically dispersed
chassis are connected in this way, the combination is called a virtual chassis
chain.

Physical Chaining

Independent Ixia 400T, 1600T, Optixia XL10, Optixia XM12, Optixia XM2, or
Optixia X16 chassis may synchronize themselves with other chassis as shown in
the following figure. The timing choices are explained in
Figure 2-3. Physical Chaining
Table 2-2. Physical Chaining Timing Choices
Choice Usage
Internal Sync If a chassis is used in a standalone manner or the master
(Synchronous) of a chassis chain, it may generate its own start signal. In
general, there is insufficient timing accuracy between
timing masters for measurements over any distance. This
is also known as the Synchronous Timing mode.
Sync-In (SI) If a chassis is a subordinate, either directly connected to
the master chassis or further down the chain, it derives its
timing from the previous chassis' Sync-Out (SO) signal.
Ixia Hardware and Reference Manual, Release 6.20
Table 2-2.