From: Peretz Feder [mailto:pfeder@lucent.com]
Sent: Wednesday, September 06,
2006 4:52 PM
To: Gupta, Vivek G
Cc: STDS-802-21@listserv.ieee.org
Subject: Re: [802.21] SAP
semantics
Vivek, pls see
in line (red):
"The L2 transport functions
are provided by media specific SAPs. The L3 transport functions may be provided
by other higher layer services. I don’t see the need to
introduce another SAP for these transport functions."
Pls. look at the attached, it is exactly what you are
indicating here. The proposed MIH-NET-SAP is an explanation and illustration of
what you have just described:
The L2 transport functions are
provided by media specific SAPs.
In the attached pls note the media specific text
The L3 transport functions may
be provided by other higher layer
That too is described in the mapping exercise. We are not proposing a new SAP,
just map it properly to L2 and L3.
Peretz Feder
On 9/6/2006 5:00 PM, Gupta, Vivek G wrote:
Some comments below.
Best Regards
-Vivek
Ajay Rajkumar
wrote:
Hong-Yon,
I agree that SAP is defined to provide an abstraction between a service
provider entity and a user entity.
Also, MIH protocol would be used to provide communication between the two MIHF
entities.
The problem arises from the current text in the draft in Section 5.6
"Upper layers may directly send commands to MIHF. Similarly MIHF entity
may also
send commands to another remote (peer) MIHF entity. Primitives corresponding to
all these services
described above are within the scope of MIH_SAP."
[Vivek G Gupta]
This text can be updated. Below is a suggestion for the
second part of this paragraph in section 5.6 (pg 29 of draft D01.09)
“The MIH_SAP and associated primitives provide the
interface from MIHF to the upper layers of the mobility-management stack. Upper
layers need to register with MIHF as users to receive MIHF generated events and
also for link layer events that originate at layers below the MIHF but may be
passed on to upper layers through MIHF. Upper layers may directly send
commands to MIHF. Similarly MIHF entity may also send
transport these commands and events to another remote (peer) MIHF entity. Primitives corresponding to all
these services described above are within the scope of MIH_SAP. The L2 transport functions are
provided by media specific SAPs. The L3 transport functions may be provided by
other higher layer services.”
I don’t see the need to introduce another SAP for
these transport functions.
This implies that MIH_SAP is being used both by the MIH User as well as MIHF to
communicate with the remote entity, which is my view is incorrect.
[Vivek G Gupta]
MIHF does not use MIH_SAP. That notion is indeed incorrect.
The first sentence in paragraph above (copied below)
illustrates that clearly as well.
“The MIH_SAP and associated primitives provide the
interface from MIHF to the upper layers of the mobility-management stack”
Regards,
-ajay
Hong-Yon Lach wrote:
Salut all,
A SAP is defined to provide an abstraction of service between a service
provider entity and its user entities in the local system. A protocol provides
a specification of interactions and operations between “peer”
entities in different (sometimes virtual) systems with well-defined PDUs
exchanges over a communications transport.
If a local MIH-user needs a remote services by a remote MIHF, it makes its
request to the local MIHF through the MIH SAP. The local MIHF determines that
it needs the support of a remote MIHF, it thus performs the necessary
operations with the remote MIHF using the MIH protocol. Upon the end of the MIH
protocol operation, the local MIHF provides a response to the MIH-user via the
MIH SAP.
An entity can initiate the execution of its function and/or protocol by many
different triggers: timeout of a timer, request by its users, detection of
certain system conditions, reception of a PDU from its peer, etc. The entity
can initiate its function and/or protocol without going through its SAP. A SAP
is not the only means to have its serving entity to initiate a function and/or
protocol.
I hopes this addresses your concerns.
Cheers,
Hong-Yon