5 Jun 2006 14:26
V3 related clarifications required
Sudhanshu Garg <sudhanshu.garg <at> flextronicssoftware.com>
2006-06-05 12:26:32 GMT
2006-06-05 12:26:32 GMT
Hi,
While going through the H.248.1 V3 I had following queries.
Could someone please answer them. Protocol enhancements are also suggested for some of them. Please also comment on them if they are correct and feasible or not.
Queries related to context attribute descriptor and context Audit
Query 1:
The context Id list has been introduced in H.248.1 in context attribute descriptor.
The usage has also been explained for the auditing purpose in section 7.2.5. Can the context Id list be used for other command requests as well?
For example if IMGC needs to tear down some calls selectively, can following Megaco transaction be used?
MEGACO/3 [x.x.x.x]:x Transaction=10001{Context=*{ContextAttr{ContextList={1,2}},Subtract=*{Audit{}}}}
If yes then, what will be the corresponding reply:
a) MEGACO/3 [y.y.y.y]:y Reply=10001{Context=*{ContextAttr{ContextList={1,2}},Subtract=*}}
or
b) MEGACO/3 [y.y.y.y]:y Reply=10001{Context=1{Subtract=t1, Subtract=t2}, Context=2{Subtract=t3, Subtract=t4}}
or
c) anything else.
And also, it should be mandatory to have wildcarded context ID (context=*), if context attribute descriptor has context ID list.
Query 2:
The termination ID list has been introduced in H.248.1 where a hierarchical TerminationID structure is not possible.
When service change command request is sent then whether the termination ID ROOT can be present with other terminations simultaneously in the termination ID list or not.
e.g. MEGACO/3 [y.y.y.y]:y Transaction=2000{Context=-{ServiceChange=[ROOT, T1]{Services{Method=Forced, Reason="907 Transmission failure",20060602T04044100}}}
It means that termination T1 and MG as a whole are taken out of service (where T1 also belongs to same MG) and here taking T1 out of service is redundant.
Query 3:
ASN syntax supports sequence of IndAudPropertyParm in ContextAttrAuditRequest. Does it mean
a) auditing of multiple packages is allowed
or
b) auditing of only a single package with a selection criteria of multiple property parameters is allowed.
If answer is "a" then to audit package P1 and P2 with the selection criteria being properties p3, p4 and p5, single action request is sufficient and sequence of IndAudPropertyParm in ContextAttrAuditRequest should be provided as follows:
Action request 1:
IndAudPropertyParm 1:
name P1
propertyParms p3
IndAudPropertyParm 2:
name P1
propertyParms p4
IndAudPropertyParm 3:
name P1
propertyParms p5
IndAudPropertyParm 4:
name P2
propertyParms p3
IndAudPropertyParm 5:
name P2
propertyParms p4
IndAudPropertyParm 6:
name P2
propertyParms p5
If answer is "b" then to audit package P1 and P2 with the selection criteria being properties p3, p4 and p5, two action requests are necessary and sequence of IndAudPropertyParm in ContextAttrAuditRequest should be provided as follows:
Action request 1:
IndAudPropertyParm 1:
name P1
propertyParms p3
IndAudPropertyParm 2:
name P1
propertyParms p4
IndAudPropertyParm 3:
name P1
propertyParms p5
Action request 2:
IndAudPropertyParm 1:
name P2
propertyParms p3
IndAudPropertyParm 2:
name P2
propertyParms p4
IndAudPropertyParm 3:
name P2
propertyParms p5
On the same hand, the ABNF encoding does not allow me to provide the flexibility to audit multiple packages simultaneously.
Snip from ABNF syntax is also attached.
; at-most-once except contextAuditSelector
contextAuditProperties = (TopologyToken / EmergencyToken /
PriorityToken /IEPSToken/ pkgdName /
contextAuditSelector)
Query 4:
In ABNF syntax, the usage of indAudcontextAttrDescriptor in contextAudit is not very clear as the individual audit also maps on to contextAuditProperties only.
Snip from ABNF syntax is also attached.
contextAudit = ContextAuditToken LBRKT (contextAuditProperties
*(COMMA contextAuditProperties)) /
indAudcontextAttrDescriptor RBRKT
indAudcontextAttrDescriptor
= ContextAttrToken LBRKT contextAuditProperties
*(COMMA contextAuditProperties) RBRKT
Query 5:
The usage of context Id list inside the contextAuditSelector (using contextAttrDescriptor) is not very clear. The ASN syntax does not have context Id list in ContextAttrAuditRequest.
IF context ID list is not required in the contextAuditSelector, then the corresponding ABNF should be updated to have list of propertyParm instead of contextAttrDescriptor.
Suggested ABNF:
; at-most-once
contextAuditSelector = priority / emergencyValue / iepsValue /
contextAttrSelector / auditSelectLogic
contextAttrSelector = ContextAttrToken LBRKT (propertyParm *(COMMA propertyParm)) RBRKT
Snip from existing ABNF syntax and ASN syntax is also attached.
ABNF Syntax:
contextAudit = ContextAuditToken LBRKT (contextAuditProperties
*(COMMA contextAuditProperties)) /
indAudcontextAttrDescriptor RBRKT
; at-most-once except contextAuditSelector
contextAuditProperties = (TopologyToken / EmergencyToken /
PriorityToken /IEPSToken/ pkgdName /
contextAuditSelector)
; at-most-once
contextAuditSelector = priority / emergencyValue / iepsValue /
contextAttrDescriptor / auditSelectLogic
contextAttrDescriptor = ContextAttrToken LBRKT (contextIdList /
propertyParm *(COMMA propertyParm)) RBRKT
ASN Syntax:
ContextAttrAuditRequest ::= SEQUENCE
{
topology NULL OPTIONAL,
emergency NULL OPTIONAL,
priority NULL OPTIONAL,
…,
iepscallind NULL OPTIONAL,
contextPropAud SEQUENCE OF IndAudPropertyParm OPTIONAL,
selectpriority INTEGER(0..15) OPTIONAL,
-- to select given priority
selectemergency BOOLEAN OPTIONAL,
-- to select if emergency set/not set (T/F)
selectiepscallind BOOLEAN OPTIONAL,
-- to select if IEPS set/not set (T/F)
selectLogic SelectLogic OPTIONAL -- default is AND
}
SelectLogic ::= CHOICE
{
andAUDITSelect NULL, -- all filter conditions satisfied
orAUDITSelect NULL, -- at least one filter condition satisfied
…
}
Regards,
Sudhanshu.
Technical Leader
Flextronics Software Systems
Phone: +91-124-4176301 extn 5109
Fax: +91-124-4300247
web: www.flextronicssoftware.com
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