H.248 Ia Profiles: Admission Control vs Traffic Policing; RE: Help needed

Giri,
 
your questions are related to ETSI TISPAN.
Responses see inline.
 
Albrecht
 



________________________________

	From: [email protected] [mailto:[email protected]]
On Behalf Of shashanka bhat
	Sent: Donnerstag, 2. April 2009 10:21
	To: [email protected]
	Subject: [Megaco] Help needed
	
	
	Hi All, 
	
	  1) Is b= line mandatory in ADD Ia request ?.
[[Schwarz, Albrecht]]  see ETSI ES 283 018 for Ia V1 & V2, and 183 018
for Ia V3
Please note that the semantic of the "b=" line did change between V1 &
V2:

Tab. 87: NOTE 5:	It has to be noted that Ia profile version 1 has
a different semantic (see table 81 in ES 283 018 [22]) defined, which
incorporates also layer 2 bitrate.
A transformation between both "b=" line usages (in case of IP-over-L2)
is not straightforward because the transformation parameters are based
on L2-PCI and the IP packet rate. The L2-PCI is typically constant for a
dedicated L2 technology (like IP-over-IEEE 802.3 [i.9]), but the packet
rate is application-specific. E.g. the IP packet rate is usually unknown
at Ia for media-agnostic IP-to-IP interworking.

	
	  2) Can we use TMAN package instead of b= line ?.
[[Schwarz, Albrecht]]  No, not per se. You know that the two protocol
"tools" serve different purposes:
a) Admission Control (AC) => "b=" line provides input information for
the StAC (Stream Admission Control), which is related to transport
capacity reservation and allocation ... typically based on a CBR model
(i.e. peak-rate allocation) ... dependent of "b=AS:" semantic ...
b) Traffic Policing (TP) => tman is used for IP byte-rate policing
(which has nothing to do with AC)


=> that's the starting point of H.248 Ia Profile
=> any re-use of AC parameters for TP, or TP parameters for AC, may be
not excluded and is possible (with some limitations)
=> see Ia V2, clause 5.17.1.5 Bandwidth control - Reservation,
Allocation and Policing


	
	Cheers,
	Giri Prasad.