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D14049.04
JULY 2008
Grey Headline (continued)
TANDBERG VIDEO COMMUNICATIONS SERVER
ADMINISTRATOR GUIDE
Introduction Getting Started
Overview and
Status
System
Conguration
VCS
Conguration
Zones and
Neighbors
Call
Processing
Bandwidth
Control
Firewall
Traversal
Appendices
Applications Maintenance
Searches and Transforms
Zone Search and Transform Process
Zones searching takes place after call policy has been applied.
The zone search and transform process is applied to the Local
Zone and all other external zones simultaneously, and is as
follows:
The VCS looks at all matches for the Local Zone and all 1.
external zones to nd those with either:
a
•
Mode of AlwaysMatch, or
a
•
Mode of PatternMatch and a Pattern String that matches
the alias being searched for.
These matches are listed in order of the 2. Priority that has been
assigned to them.
If there are any duplicates in the list, the entry with the lower 3.
Priority is removed. (This applies to a zone with the same
pattern string and the same transform but different priorities.)
If there is a zone which has an 4. AlwaysMatch as well as
a PatternMatch with no transforms, the PatternMatch is
removed from the list.
All zones with a Priority 1 match on the list are queried using 5.
the same protocol (i.e. SIP or H.323) as the incoming call
request. For AlwaysMatch matches, the query will use the
original alias; for PatternMatch matches the query will use the
alias specied by the transform rules.
If the alias is found, the call will be forwarded to that zone. 6.
If the alias is found by more than one zone, the call will be
forwarded to the zone that responded rst.
If the alias is not found using the native protocol, the query 7.
is repeated (as per steps 5 and 6) using the interworked
protocol.
If the alias is not found, all zones with a Priority 2 match are 8.
queried as per steps 5 to 7.
The process is repeated with subsequent Priority levels until 9.
either:
the alias is found, or
•
all zones with a match that meets the specied criteria
•
have been queried.
Zone Searching and Transforming
About Zone Transforms
The VCS allows you to change the alias being searched for
before a search request is sent to the Local Zone or out to a
particular zone. This feature uses the PatternMatch mode of the
zone search function.
To set up a zone transform, you must:
congure the zone with a
•
Mode of PatternMatch
specify the pattern that the alias to be transformed must
•
match
specify the way in which the alias will be transformed.
•
All searches that match the specied pattern will then be
transformed when sent to the zone, and the zone will be queried
using the new alias.
About Zone Searching
The VCS allows you to lter the search requests sent to each
zone, including the Local Zone, and prioritize the order in which
these zones are searched. This allows you to reduce the
potential number of search requests sent out, and speed up the
search process.
The VCS uses the concept of zone “matches” to lter search
requests. Each zone has up to ve congurable “matches”
available to it. Each match is assigned a Mode and Priority
(described below). The combination of the two determines if and
when that zone will be queried.
Using Zone Searches and Transforms Together
The zone searching feature and the zone transforms feature
both make use of the PatternMatch mode. You can use these
two features together or separately.
The remainder of this section:
describes the
•
zone search and transform process
explains how to
•
congure zone searches and transforms
gives some
•
examples of how zone searches and transforms
could be used together.
It is possible for the same priority to be given to more
than one match, either in the same zone or in different
zones. In this case, all zones with that match priority will
be queried at the same time.
Match Mode
The match Mode allows you to specify whether and how
requests to the zone will be ltered. You can also use this mode
to prevent search requests from ever being sent to the zone.
The Mode options are:
AlwaysMatch
•
: always query the zone
PatternMatch
•
: only query the zone if the alias being searched
for matches a specied pattern
Disabled
•
: never query the zone (this mode does not need a
corresponding Priority option).
Match Priority
The match Priority allows you to specify when in the search
process that zone will be queried. Search requests are sent to
all zones with a Priority 1 match rst, followed by all zones with
Priority 2 matches, and so on.
Each zone has up to ve congurable matches. This
means that you can specify up to ve different
transforms for each zone. This could be:
one alias or string transformed ve different ways
•
ve aliases or strings each transformed individually
•
a combination of both.
•
Zone transforms support the use of Regular Expressions
in both the Pattern String and Replace String
elds. See the Appendix Regular Expression Reference
for more information.