Subject: Cisco SG16: DigitMaps

From: Chip Sharp <[email-masked]>
Date: Tue, 25 Jan 2000 18:57:35 -0500

Section:        7.1.13
Category:       Technical
Issue:          The draft text does not include any rules for when the "current
dial string" is cleared. Rules in this area are needed to provide
consistent operation
Proposal:       It is proposed that the "current dial string" is cleared whenever
a notification occurs, or an Embedded Events Descriptor is activated.

v13 Status:     OPEN. No relevant text added.

Section:        7.1.13, bullet list
Category:       Technical
Issue:          The draft text specifies that digit maps are shared if they are
applied to multiple terminations through wildcarded commands. Furthermore,
the second bullet specifies that "A DigitMap value is updated by supplying
a new value for a name that is already defined". When a shared named digit
map is later changed in a command that is applied only to a particular
termination, this will then modify other terminations view of the digit
map. Furthermore, it is unclear what will happen to any ongoing digit map
matching that is in process at the time this happens.
Proposal:       It is recommended, that when a shared named digit map is modified
in a command that is applied to a termination, the termination does a
copy-and-write and only the termination's digit map is modified; the shared
named digit map is not affected.
v13 Status:     OPEN. No text changed.

Section:        7.1.13, second paragraph.
Category:       Technical
Issue:          The draft text specifies that "A DigitMap, once defined, can be
used on all Terminations specified by the (possibly wildcarded)
TerminationID in such a command". This definition effectively prevents
ephemeral terminations from referencing DigitMaps by name, as ephemeral
terminations cease to exist once they are subtracted from a context. An
example application that might want to use DigitMaps on ephemeral
terminations is an IVR.
Proposal:       It is recommended, that the mechanism is extended to allow
ephemeral terminations to reference a set of DigitMaps by name as well,
e.g. by defining a global digit map name space.

v13 Status:     OPEN. No text changed.

Section:        7.1.13, third paragraph and second number list item.
Category:       Technical/Editorial
Issue:          The draft text for numbered items 2 and 3 specify that "If the
Media Gateway can determine that at least one more digit is needed for a
digit string to match any of the allowed patterns in the digit map, then
the interdigit timer value should be set to a long duration (e.g. 16
seconds)" and "If the DigitMap specifies that a variable number of
additional digits may be needed then the short timer is used". However,
this text specifying an algorithm for determining the current value of the
interdigit timer is inconsistent with the definition of digit map given in
Annex A.3 where two explicitly different timers are defined for the digit
map, hence overriding the algorithm just specified (also note, that there
is an inherent problem in using multiple timer symbols, in that a given
current dial string may match multiple entries in a digit map, one of which
may specify a short timer, and one of which may specify a long timer  which
timer should then be used ?)
Proposal:       It is proposed that the algorithm is retained and only a single
timer symbol ("T") be allowed in digit maps thereby making timer
determination simple and deterministic.

v13 Status:     OPEN. No relevant text changed.

Section:        A.3
Category:       Technical
Issue:          The draft text specifies that two different timer symbols ("S" and
"L") for short and long can be used for digit map timers. Cf. earlier
comment on the use of multiple timer symbols in digit maps, this is
inconsistent with the digit map algorithm specified in Section 7.1.3.
Proposal:       It is recommended to replace the timer symbols "S" and "L" with a
single timer symbol "T" and rely on the algorithm specified in Section
7.1.3. This will furthermore remove the current grammar ambiguity that
exists for the strings "S0", "S1", "S2", and "S3" (MFSig or a short timer
followed by a digit).

v13 Status:     OPEN. Note that Section 7.1.14 now specifies that "S0" etc. are
not valid digit map symbols thereby removing the above ambiguity, but the
digit map grammar in Annex A.3 has not been modified.

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Chip Sharp                 Consulting Engineering
Cisco Systems              Telco Bio-region
Reality - Love it or Leave it.
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