Re: [STDS-802-16] T16 Clarification
Your argument is uncompelling. The language of D5,
while not completely unambiguous, is clear enough.
Your specific example is not convincing. The
paragraph only indicates where MAC management messages are mapped. It DOES
NOT say that ONLY MAC management messages are mapped to the Basic and Primary
CIDs. It simply says where MAC management messages map to.
Also, Figure 95 is hardly compelling either. It
merely shows that CID must have a common QoS Parameter Set, which makes sense
since bandwidth requests are made based on CID, not SFID.
The reality is that under the language for the DSA
& DSC MAC management messages and/or section 6.3.14 QoS, the document
language would have to explicity state that data service flows
provisioned through the DSx mechanics cannot be mapped to the Basic or Primary
CIDs. It does not. In fact, 6.3.14.9.4 DSC, page 249, line 31, and 6.3.14.9.5
Connection release, page 260, line 4, specifically cover the instance of when
the service flow is cancelled and it is mapped to the Basic, Primary, or
Secondary management CID. Obviously this language would not be present if SFIDs
could not map to those special CIDs.
Also, to support the other part of your assertion,
the language of DSA & DSC MAC management messages and/or section 6.3.14 QoS
would necessarily need to be very clear that a CID would only be permitted to
have a single SFID mapped to it. It does not. And this despite many opportunities in the document for such clarity. This
cannot be perceived as some oversight since the document does make special
effort to identify the unique nature of SFID. So, in the absense of clear
definition, multiple SFID mapping to a single CID must be assumed as
permissable.
So I am afraid that I must disagree with your
interpretation of the current language in the IEEE 802.16-2004
document.
I draw your attention to the following relevent
sections of language:
3. Definitions
page 7, line 52
3.12 connection: A unidirectional mapping between base
station (BS) and subscriber station (SS) medium access control (MAC) peers for
the purpose of transporting a service flow’s traffic. Connections are identified
by a connection identifier (CID). All traffic is carried on a connection, even
for service flows that implement connectionless protocols, such as Internet
Protocol (IP). See also: connection identifier.
3.13 connection identifier (CID): A16-bit value that
identifies a connection to equivalent peers in the MAC of the base station (BS)
and subscriber station (SS). It maps to a service flow identifier (SFID), which
defines the Quality of Service (QoS) parameters of the service flow associated
with that connection. Security associations (SAs) also exist between keying
material and CIDs. See also: service flow identifier.
6.3.1.1 PMP
page 33, line 16
Each SS shall have a 48-bit universal MAC address, as
defined in IEEE Std 802-2001. This address uniquely defines the SS from within
the set of all possible vendors and equipment types. It is used during the
initial ranging process to establish the appropriate connections for an SS. It
is also used as part of the authentication process by which the BS and SS each
verify the identity of the other.
Connections are identified by a 16-bit CID. At SS
initialization, two pairs of management connections (uplink and downlink) shall
be established between the SS and the BS and a third pair of management
connections may be optionally generated. The three pairs of connections reflect
the fact that there are inherently three different levels of QoS for management
traffic between an SS and the BS. The basic connection is used by the BS MAC and
SS MAC to exchange short, time-urgent MAC management messages. The primary
management connection is used by the BS MAC and SS MAC to exchange longer, more
delay-tolerant MAC management messages. Table 14 specifies which MAC Management
messages are transferred on which of these two connections. Finally, the
Secondary Management Connection is used by the BS and SS to transfer delay
tolerant, standards-based [Dynamic Host Configuration Protocol (DHCP), Trivial
File Transfer Protocol (TFTP), SNMP, etc.] messages. These messages are carried
in IP datagrams, as specified in 5.2.6. Messages carried on the Secondary
Management Connection may be packed and/or fragmented. For the SCa, OFDM, and
OFDMA PHY layers, management messages shall have CRC. Use of the secondary
management connection is required only for managed SS.
The CIDs for these connections shall be assigned in the
RNG-RSP and REG-RSP messages. The message dialogs provide three CID values. The
same CID value is assigned to both members (uplink and downlink) of each
connection pair.
For bearer services, the BS initiates the set-up of
connections based upon the provisioning information distributed to the BS. The
registration of an SS, or the modification of the services contracted at an SS,
stimulates the higher layers of the BS to initiate the setup of the
connections.
The CID can be considered a connection identifier even for
nominally connectionless traffic like IP, since it serves as a pointer to
destination and context information. The use of a 16-bit CID permits a total of
64K connections within each downlink and uplink channel.
Requests for transmission are based on these CIDs, since the
allowable bandwidth may differ for different connections, even within the same
service type. For example, an SS unit serving multiple tenants in an office
building would make requests on behalf of all of them, though the contractual
service limits and other connection parameters may be different for each of
them.
Many higher layer sessions may operate over the same wireless
CID. For example, many users within a company may be communicating with
Transmission Control Protocol (TCP)/IP to different destinations, but since they
all operate within the same overall service parameters, all of their traffic is
pooled for request/grant purposes. Since the original local area network (LAN)
source and destination addresses are encapsulated in the payload portion of the
transmission, there is no problem in identifying different user
sessions.
The type of service and other current parameters of a service
are implicit in the CID; they may be accessed by a lookup indexed by the
CID.
6.3.14.1 Theory of operation
page 221, line
2
All service flows have a 32-bit SFID; admitted
and active service flows also have a 16-bit CID.
6.3.14.2 Service flows
page 221, line
18
a) Service Flow ID: An SFID is assigned to
each existing service flow. The SFID serves as the principal identifier for the
service flow in the network. A service flow has at least an SFID and an
associated Direction.
b) CID: Mapping to an SFID that exists only when the
connection has an admitted or active service flow.
6.3.14.3 Object model
page 223, line 10
The service flow is the central concept of the MAC
protocol. It is uniquely identified by a 32-bit (SFID). Service flows may be in
either the uplink or downlink direction. Admitted and active service flows are
mapped to a 16-bit CID.
Outgoing user data is submitted to the MAC SAP by a CS process
for transmission on the MAC interface. The information delivered to the MAC SAP
includes the CID identifying the connection across which the information is
delivered. The service flow for the connection is mapped to MAC connection
identified by the CID.
6.3.14.9.4 DSC
page 249, line 31
Any service flow can be deactivated with a DSC command by
sending a DSC-REQ message, referencing the SFID, and including a null
ActiveQoSParamSet. However, if a Basic, Primary Management, or Secondary
Management Connection of an SS is deactivated, that SS is deregistered and shall
re-register. Therefore, care should be taken before deactivating such service
flows. If a service flow that was provisioned is deactivated, the provisioning
information for that service flow shall be maintained until the service flow is
reactivated.
6.3.14.9.5 Connection release
page 260, line
4
Any service flow can be deleted with the DSD
messages. When a service flow is deleted, all resources associated with it are
released. If a service flow for a provisioned service is deleted, the ability to
re-establish the service flow for that service is network management dependent.
Therefore, care should be taken before deleting such service flows. However, the
deletion of a provisioned service flow shall not cause an SS to
reinitialize.
Thanks,
Phil
----- Original Message -----
Sent: Monday, September 06, 2004 2:52
AM
Subject: Re: [STDS-802-16] T16
Clarification
> Absolutley not!! SFIDs and CIDs exist with a one-to-one mapping.
Note
> that management messages that create connections use SFIDs as
the
> primary identifier to do so, not CIDs. Also, note Figure 95 (in
D5)
> which indicates that there is a one-to-one mapping between SFID/CID
when
> a connection (aka CID exists).
>
> Also arbitrary
traffic may not be assigned to the Basic/Primary
> connections. This is
explicitly stated in 6.3.1.1 of D5:
>
> "The basic connection is
used by the BS MAC and SS MAC to exchange
> short, time-urgent MAC
management messages. The primary management
> connection is used by the BS
MAC and SS MAC to exchange longer, more
> delay-tolerant MAC management
messages."
>
>
> -----Original Message-----
> From:
owner-stds-802-16@LISTSERV.IEEE.ORG
> [mailto:owner-stds-802-16@LISTSERV.IEEE.ORG] On Behalf Of Phillip
Barber
> Sent: Sunday, September 05, 2004 8:48 PM
> To: STDS-802-16@LISTSERV.IEEE.ORG
>
Subject: Re: [STDS-802-16] T16 Clarification
>
> Absolutely. The
standard is designed to allow function of mapping one or
> more SFIDs (UL
and/or DL agnostic) to any of the Active CIDs for the SS.
> That includes
the Basic and Primary CIDs. Typically, Service Flows with
> attributes
that require low latency would map to one of the higher
> priority
>
CIDs like Primary or even Basic. With less demanding Service Flows, like
>
Best Effort types, you would typically create a temporary CID for the SS
>
to
> map these Service Flows into, so as not to place low priority
traffic
> into
> high priority Primary and Basic CIDs. This method
of allocating multiple
> SFIDs to a limited number of CIDs permits more
effective conservation of
> the
> scarce CID management/allocation
space.
>
> Thanks,
> Phil
>
> ----- Original
Message -----
> From: <mchion@ztesandiego.com>
> To:
<STDS-802-16@listserv.ieee.org>
> Sent: Sunday, September 05, 2004 5:31 PM
> Subject:
Re: [STDS-802-16] T16 Clarification
>
>
> > Phil,
>
>
> > Since we are on this subject, does the standard (in your
opinion)
> allows
> > multiple DL SFIDs or multiple UL SFIDs map
to one CID at one BS?
> >
> > Thanks.
> >
>
> Mary
> >
> >
> > Original Message:
> >
-----------------
> > From: Phillip Barber pbarber@BROADBANDMOBILETECH.COM
> > Date: Sun, 5 Sep 2004 11:03:55 -0500
> > To: STDS-802-16@listserv.ieee.org
>
> Subject: Re: [STDS-802-16] T16 Clarification
> >
>
>
> > IEEE 802.16-2004, 6.3.14.2 Service flows, page 220, line 8
says 'a
> service
> > flow is a MAC transport service that
provides unidirectional transport
> of
> > packets either to
uplink packets transmitted by the SS or to downlink
> > packets
transmitted by the BS....' and line 18 says 'An SFID is
> assigned
>
to
> > each existing service flow. The SFID serves as the
principal
> identifier
> for
> > the service flow in the
network. A service flow has at least an SFID
> and
> an
> >
associated Direction.' So neither of these sentences say that the
>
SFID
> > must be unique and cannot be common between multiple service
flows,
> though
> > the language does indicate that the SFID must
be to either a UL or DL
> > service flow, not both. However, section 3.
Definitions, page 10, line
> 52,
> > '3.52 service flow
identifier (SFID): A 32 bit quantity that uniquely
> > identifies a
service flow to both the subscriber station and base
> station
>
> (BS)...' is very specific and requires that the SFID be unique for
>
that
> > specific service flow. So the answer to your question is, NO,
the SFID
> > cannot be used for both the DL and UL of some similar
service flows,
> though
> > they may share the same CID.
>
>
> > Thanks,
> > Phil
> >
>
> ----- Original Message -----
> > From:
Eyal Verbin
> > To: STDS-802-16@listserv.ieee.org
>
> Sent: Sunday, September 05, 2004 6:53 AM
>
> Subject: Re: [STDS-802-16] T16 Clarification
>
>
> >
> > The standard allows a situation in
which a certain CID is used for a
> > certain DL SFID and the same CID
is used for another UL SFID. Does the
> same
> > approach apply
for the SFID, i.e. can a certain SFID be used for UL
> and DL
> >
connection and be distinguished by the TLV type [145/146]
> >
>
>
> >
> > Eyal
> >
>
>
> >
> >
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