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Dear Yigal Leiba, Yigal
Eliaspur, and All. I think Yigal at Runcom and
Yigal at Intel have different concept of using the Secondary management
connection. In my understanding of your
comments, you mean that ¡°the management function of the mobile device (regardless
of what management function such as DHCP, Mobile IP, or TFTP download) can be
done on top of the MAC rather than inside it.¡± But, the current (draft)
standard and the result of the comment resolution of the last meeting (Comment
#580, #581) say that ¡°Finally, the Secondary Management Connection is may
be used by the BS and MSS to transfer delay tolerant, standards- based [Dynamic Host Configuration Protocol
(DHCP),Trivial File Transfer Protocol (TFTP), SNMP, etc.] management messages.
These management messages are terminated at the MSS.¡± -- That means the management
function of the mobile device (explicitly for DHCP, TFTP, SNMP) is inside the
MAC layer using the Secondary management connection. -- The result of the comment
resolution means that deleting the text for usage of the secondary management
connection includes the Mobile IP or Router Prefix Advertisement. Therefore, the result of the
last meeting¡¯s comment resolution (#581) have the meaning of Yigal Eliaspur¡¯s
words: ¡°The current specification (16e/d) provides management
mechanism that was mostly inherited from DOCSIS specification, and was design
for fix SS (RG like) operation. This management framework requires 2 separate
IP IF, one for Data traffic and one for Management traffic. The Management
IP-IF is consider part of the 16 MAC and as a result the standard includes
explicit reference to its layer 3 and above protocols (DHCP,IP,TFTP,SNMP). E.g
: IP connectivity and TFTP stage in the network entry, the definition of
the Secondary Mgmt connection, etc.¡± But I do not agree with both of
you because if we use a transport connection for the data traffic IP management,
then the BS and the MSS will not know what transport connection ID they should use.
Since there is no procedure for
allocating the default Transport CID before they transfer the DHCP or Mobile IP
messages to/from the BS. E. Yigal says ¡°If
the network/BS cannot allocate in advance (before operational stage) a
co-located IP address based on the SS MAC address, the network/BS shell open a
default data CID with a classifiers that is agnostic to a specific IP address (e.g.
much all classifier). Once it has knowledge of the IP address and other higher
level information (like ports) the system, based on needs, can triggered
dynamic DSx with the appropriate information (note that more then one CPE IP
address is possible in RG like environments).¡± But it is not the matter of
classifier to classify the unknown IP address mapping, but the matter of
connection identifier to identify which connection they (both the BS and the
MSS) use to transport the data traffic IP management messages (DHCP, or Mobile
IP). There is no step (no management message and parameter of it) to allocate
the default connection CID, the BS and the MSS should not know on what
connection CID their DHCP or Mobile IP messages be transmitted. That means, it
is impossible to transmit the data traffic IP management messages using the
transport connection. Please let me know what
procedure they can transmit MSS-to-BS and BS-to-MSS DHCP (or Mobile IP)
messages using the transport connection. And, I would like to know that
without IP address for the data traffic, how can it carry out the DSA procedure?
We should set lots of IP address related parameters for the transport
connection using the DSA procedure. In my understanding, the
secondary management connection is used to transmit the IP management messages (M)SS
to/from BS, then they can be allocated the IP address for the data traffic, and
then they can carry out the DSA procedure using the IP address and the QoS
related parameters. If I accept the E. Yigal¡¯s concept,
there should be the step of default transport connection CID allocation provided
during the network entry procedure, and handover procedure. Anyway, the current specification
should be modified appropriately. I also do not agree with E.
Yigal¡¯s following comment: ¡°An experiment to enhance the Mgmt IP-IF to
Mobile operation by replacing DHCP with MIP was a failure as for the amount of
complexity it brought. The aim of 16g is to define applicable and scale Mgmt
solution for mobile operation, and this might be done using MAC layer Mgmt
singling (not IP/SNMP based).¡± We (ETRI) have successfully implement
the Mobile IP operation using the Secondary management connection without any complexity
problem. I would like to know the details
of what¡¯s your experiment and what¡¯s the problem for not supporting the Mobile
IP on the secondary management connection. And I think that it is not for
the matter of management layer signaling, but it is the matter of MAC layer. Therefore, I insist that the original
text in the P802.16e/D4 or the comment from the Bob Nelson (Comment #580) says
more appropriate: ¡°Replace
(P802.16e/D4 text) Finally, the Secondary Management
Connection is used by the BS and MSS to transfer delay tolerant, standards-based
[Dynamic Host Configuration Protocol (DHCP), router prefix advertisements, Mobile
IP, Trivial File Transfer Protocol (TFTP),
SNMP, etc.] management messages. These management messages are terminated at
the MSS. with (base text taken from REVd ) 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. For BS/MSS connections, router
prefix advertisements and Mobile IP management messages may also be carried.
Messages carried on the Secondary Management Connection are terminated at the
SS or MSS.¡± I think that the original text
in the P802.16e/D4 or the comment from the Bob Nelson (Comment #580) says more
appropriate: Best Regards, Chulsik Yoon, Senior Engineer, ETRI From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org] On
Behalf Of Yigal leiba Dear Chulsik, I think our disagreement results from a very fundamental fact. This
fact is that I believe that the management function of the mobile device can be
done on top of the MAC rather than inside it. What this means is that it is not
necessary for the MAC to define DHCP or Mobile-IP or TFTP download or any of
these things. It is sufficient to define a management interface (like a MIB),
and then after the MSS is connected to the network, open a management
connection (which is a normal transport connection from the MAC point of view,
but used for management from the system point of view) and manage the MSS to
your heart's desire. This approach simplifies things, since in the MAC level
there is no special treatment to this connection (not to mention that it does
not need an IP stack now, HO is faster, etc.). I hope this clarifies what I said in the meeting. BR, Yigal From: owner-stds-802-16@listserv.ieee.org
[mailto:owner-stds-802-16@listserv.ieee.org] On
Behalf Of ??? Hello Yigal, I would like to discuss the usage of the Secondary
Management Connection. In the current draft standard, the usage of the
secondary management connection is described like this (it is the result of the
last meeting in ¡°Finally, the Secondary Management Connection is used
by the BS and MSS to transfer delay tolerant, standards-based [Dynamic Host
Configuration Protocol (DHCP), Trivial File Transfer Protocol (TFTP), SNMP,
etc.] management messages.¡± -- The text having the meaning that Mobile IP messages
and router prefix advertisement are not transferred through the secondary
management connection. We have talked about the issues in the meeting, but we
have found out some differences in our understanding, and the problems in the
current specification. You said: But, these ideas have some problems: 1) You mean that the protocol layer for the SS management (i.e., SNMP)
is within the layer 2 (MAC) of the SS, and the path to that is on the Secondary
Management Connection. And the user traffic (even in the case of DHCP or Mobile
IP message for the IP address allocation for the user traffic) cannot use the
secondary management connection. 2) If we shall use the default transport connection for the IP
connectivity management for the user traffic, then the DSA procedure should be
proceeded before the allocation of the ¡°default transport CID¡± for the user.
But, generally DSA procedure requires the IP address for the transport
connection, and even if it is not required, the ¡°default transport connection¡±
allocation is not possible. If we use the transport connection for the transfer
of the Mobile IP and/or DHCP messages for the IP connectivity for the user
traffic, then the IP address related parameters for the DSA procedure cannot be
set. That means the parameters required should already be known to the SSs and
the BSs. The default parameters should be used. 3) If we should use the (default) Transport CID for IP connectivity
management for the user traffic, then every terminal shall maintain the Basic
CID, Primary Management CID, Secondary Management CID, and default Transport
CID for signaling/control. That means SS should have minimum 4 CIDs , but the
specification say that the minimum required CIDs each SS should have shall be
not four but three. So, the usage of default Transport CID violates the
specification. 4) If we use Transport CID instead of Secondary Management CID for the
IP connectivity management for the user traffic, then the additional DSA-REQ/RSP
procedures should be included in the network entry process. The DSA (connection
establishment) procedure must be preceded for the transaction of the IP
connectivity management procedures (DHCP or Mobile IP), because we should use
the connection established before the transaction. But, if we use the Secondary
management CID for that transaction, then the connection establishment
procedure is not required. That means, the usage of the (default) Transport
connection have more signaling overhead and causes more delay during the
network entry process. 5) In the fixed environment, a subscriber station (SS) can be separated
with equipment for the user traffic (such as multiple TEs) and the equipment
for the air interface (such as MT), so that the Secondary management connection
for the IP-based external management for the SS is feasible. But, generally in
the mobile environment, the two equipment (TE and MT) should be integrated and
used by only one user, so the separation of the path for the user traffic IP
connectivity management (default transport CID) and for the external
management for the MSS (Secondary Management CID) is not a good approach. 6) If we use the Secondary management connection only for the IP-based
management of the SS externally, then the IP address for the SS management and
the IP address for the user traffic (you mean, using the default transport
connection) should be different. But, the IP address for the user traffic and
the SS management can be shared, and has no problem. So, the separate IP
address allocation procedure is duplicated and cause wasting up the IP address
resources, especially in the case of MSS. 7) If we use the transport connection for the user traffic IP
connectivity management, then the CID resources should be thrown away
unnecessarily. If we can reuse the Secondary management connection, then we can
save the CID resources. 8) If we should proceed the handover process in the mobile environment
over the subnets, then the transport connection for the user traffic IP
connectivity management should be preceded before the transfer of the Mobile IP
messages, that gives us a large unwanted delay for the handover process, and
the system performance shall be greatly degraded. In summary, I would like to say my understanding and
concept, and the specification should be reflected to support that: 1) Secondary management connection can be used as a user traffic IP
connectivity management (DHCP or Mobile IP). 2) The IP address allocated by the DHCP procedure using the Secondary
management connection, can be shared for the user traffic and the external
management for the SS. So, there is no need to separate the path to the SS
management and the user traffic by secondary management connection and the
transport connection. 3) Mobile IP should be supported for the seamless HO across the
subnets, and for the swift handover process, the Secondary management
connection should also be used for the Mobile IP message transfer and the
external management for the MSS for the managed MSS. Best Regards, Chulsik Yoon Senior Engineer, ETRI |