T-VIPS CP525 cMux, Руководство пользователя

Страница: 38 / 292

38 Functional Description
CP525 cMux User’s Manual Rev. 5.20.12 (3944) ID: um_tsmux
The process of selecting services and unsignalled PIDs to pass can be illustrated by the flow
chart in figure
5.7 .
First, each present PID is checked for a PID configuration rule. If there is no explicit configu-
ration entry, unsignalled PIDs may be routed or stopped by a default rule. Signalled PIDs can
only be routed here if they are tagged with a pass-unconditionally rule.
Then the incoming PAT is traversed and the programs are routed in the order of which they
appear in the incoming PAT. If a program has an explicit rule, that rule is used either to stop
or forward the program. If no explicit rule is found the default rule for services on that port is
used either to stop or pass the service.
The ’Map Service’ block in the service routing diagram involves forwarding the wanted service
components for that service. This process is illustrated in figure
5.8 .
FOR EACH COMP. IN PMT
IN ORDER OF PMT,
THEN NEW CONFIGURED
COMPONENTS,
THEN PCR,
THEN ECMs
Service Mapping Start
Map PMT if mode==Pass-through
PID Rule?
Tag Rule?
Default
Include?
Global config?
Map component PID (outpid)
Exclude
Stop Sign.||
Stop Uncond.
No
No
No
Exclude
Include
Include
Global remap?
PID crash?
outpid=inpid
outpid=glob. remap
No
TX
Yes
outpid=local remap
No
Yes
No
Yes
Add program to PAT
Add component to PMT (outpid)
Service Mapping End
Figure 5.8 Service
component routing
As can be seen from the figure, service components are traversed in the order they appear in
the incoming PMT for the program. Then the same logic is applied to components merged from
other programs, and then the PCR PID before the known ECM PIDs. The order or traversal
determines which PIDs are dropped in the event of a PID conflict.
At the top of the loop we can see that the global PID table is checked for stop commands and
global re-map entries first.
PID rules are looked for before tag rules, and local re-mappings stored on either a PID rule or
a Tag rule are only used if no global remapping was found.