Grass Valley NV9000-SE v.5.0 - Manual (Page 426)

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Tielines
Introduction
A multi-hop tieline is a set of simple tielines between multiple routers, perhaps at remote
geographical locations.
Multiple tielines can be defined between routers. The NV9000 system uses tielines as a pool of
resources. When the NV9000 needs to use a tieline to perform a route, it determines all the
tielines necessary to make the route. If the pool of tielines is depleted, of course, it cannot make
the route.
Fig. 12-1: Pooled Tielines
For example, in Figure 12-1, there are no tieline paths from router 2 to router 3. If the NV9000
system cannot find a tieline path for a route, as in this case, it cannot make the route.
Free Source
Control panel operators can release a tieline by routing a local source, specifically the “free
source,” to the destination of the tieline route.
There is also a “system parameter” that, when set, automatically routes the free source to the
input of a tieline when that tieline is no longer in use. See
AUTO_FREESRC on page 498.
Tieline Groups
A tieline group couples tielines that must be used together.
The several tieline group pages and tables in NV9000-SE Utilities allow you to define and manip-
ulate tieline groups.
Output
Router 1
Router 2
Input
Router 4
Input
Output
Router 3
Input
Output
Output
Input
Output
Router 1
Router 2
Input
Router 4
Input
Output
Router 3
Input
Output
Output
Input