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Hi All, Probably we can discuss on the difference between two
approaches, either BS or MS determining the alternative path. If the
advantage/disadvantage is clear, we may be able to see which approach is
better. Regards, Shoukang From: Hoang Vinh Dien [mailto:hvdien@NICT.COM.SG]
Hi
All, Apology
if you receive multiple copy of this email. I'm re-sending using 802.16 email
reflector. Please
let me initiate the discussion for Path management topic. We have total 6
contributions (In ascending order) as follow (Each contribution was assigned
with specific color) 1.
C802.16n-rg-11/0027 2.
C802.16n-11/0028r3 3.
C802.16n-rg-11/0029 4.
C802.16n-rg-11/0036 5.
C802.16n-rg-11/0039r1 6.
C802.16n-11/0050r3 From
these 6 contributions, I had consolidated the table of content and combined
contributions together under the table of content as below. 17.2.7 Path Discovery and
Management (C802.16n-rg-11/0027,C802.16n-rg-11/0036) 17.2.7.1 Alternative Path
Definition (C802.16n-rg-11/0039r1) 17.2.7.2
Alternative Path Establishment Algorithm in a tree topology (C802.16n-rg-11/0029) 17.2.7.3
Alternative Path Establishment (C802.16n-11/0050r3, C802.16n-rg-11/0029) 17.2.7.4
Alternative Path Establishment with Multi-mode (C802.16n-rg-11/0039r1) 17.2.7.5
Alternative Path Maintenance at FS (C802.16n-rg-11/0039r1, C802.16n-11/0028r3) 17.2.7.6
Maintenance of Alternative Path(C802.16n-11/0050r3, C802.16n-rg-11/0029) 17.2.7.7
Handover to Alternative Path(C802.16n-rg-11/0029) 17.2.7.8
Failure Detection(C802.16n-11/0050r3) 17.2.7.9
Fast network re-entry after SPOF(C802.16n-11/0050r3,C802.16n-11/0028r3) Sessions 17.2.7,
17.2.7.3, 17.2.7.5, 17.2.7.6, 17.2.7.9 have two contributions each and may have
conflicts. I would like to initiate
one point of conflict between contribution 0029 and others: -
Contribution 0029
state that alternative path could be decided by BS or MS. Other contributions
mainly state that alternative path should be decided by BS only. Please have a view
on this. With my best
regards, Hoang PS: Below is the
consolidated documents. Please note that text with same color comes from same
contribution. ***** BEGIN: PATH MNG ***** 17.2.7 Path Discovery and
Management [Begin of Text Proposal: From C802.16n-rg-11/0027] [HR-Network shall
support neighbor and path discovery between HR-MSs as well as between HR-MS and
HR-Network infrastructure stations. Path discovery can be
accomplished with or without network support. HR-Network shall
support path management and establishment, removal ,updating of alternative
paths to support fast neighbor and path recovery in the event of disruption;
for example, encountering intermediate HR-MS failure or
movement. HR-Network shall provide the capability to choose the most reliable
or the least latency path. The path information could be included and passed in the signaling.] [End of Text Proposal: From C802.16n-rg-11/0027] [Begin of Text Proposal: From
C802.16n-rg-11/0036] [An HR-BS changing its
role as HR-RS may select alternative path for subordinate HR-MS in the event of
disruption. The HR-BS transmits MAC context information of the HR-MS during
establishing relay link to neighbor HR-BS to allow HR-MS to select alternative
path during performing handover to the neighbor HR-BS. The HR-BS may store
MAC context information of the HR-MS to allow HR-MS to reselect reliable path
after performing network reentry when returning back to the HR-BS upon its
recovery. When an HR-MS changes
its role as RS or returns to HR-MS from RS mode, alternative path may be
selected for subordinate HR-MS. The superordinate HR-BS may transmit MAC
context information of the subordinate HR-MS after establishing relay link to
allow the HR-MS to select alternative path.] [End of Text Proposal: From C802.16n-rg-11/0036] 17.2.7.1 Alternative Path
Definition [Begin of Text Proposal: From
C802.16n-rg-11/0039r1] An alternative path is a
link or a list of continuous links (through HR-RS or HR-MSs) between a HR-MS
and the HR-network. There are no active connections on alternative paths in
normal operation. The alternative path will only be activated when a single
point of failure is detected. 17.2.7.2
Alternative Path Establishment Algorithm in a tree topology [Begin of Text Proposal: From
C802.16n-rg-11/0029] In a tree topology, A backup tree could be
calculated as follow:
17.2.7.3
Alternative Path Establishment [Begin of Text Proposal: From
C802.16n-11/0050r3] [The alternative
path shall be determined by the serving HR-BS. The decision shall be based on
the measurement report on the links among the stations.] [End of Text Proposal: From C802.16n-11/0050r3] [Begin of Text Proposal: From
C802.16n-rg-11/0029] HR-BS determines the tree
topology of the network. From this tree topology, backup path for HR-MS will be
determined according to session 17.2.7.2. HR-BS will have higher
priority in backup path calculation. 17.2.7.4
Alternative Path Establishment with Multi-mode [Begin of Text Proposal: From
C802.16n-rg-11/0039r1] The super-ordinate HR-BS
shall determine alternative paths for every subordinate stations to prepare in
advance for SPOF events. The stations along an alternative path shall include
HR-MS or HR-BS that changes mode to relay or base-station modes if the
alternative path is a better path (e.g. more reliable) than others. 17.2.7.5
Alternative Path Maintenance at FS [Begin of Text Proposal: From
C802.16n-rg-11/0039r1] HR-BS shall maintain
alternative paths of its subordinate stations. It shall update the stations
with the alternative path information and network information to facilitate
fast network re-entry for those paths. It shall inform HR-MS which changes mode
(to HR-RS or HR-BS) of its subordinate HR-MSs and network information to
facilitate fast network re-entry of those HR-MSs.] [End of Text Proposal: From C802.16n-rg-11/0039r1] [Begin of Text Proposal: From
C802.16n-11/0028r3] The serving HR-BS shall
maintain alternative paths of its subordinate stations through FSs. It shall
periodically update FSs with a TBD message containing a list of SS it is
responsible for network re-entry after SPOF, and configuration information to
facilitate fast network re-entry. The serving HR-BS shall periodically update
its SSs with a TBD message containing their respective FS and configuration
information to facilitate fast network re-entry to that FS.] [End of Text Proposal: From C802.16n-11/0028r3] 17.2.7.6
Maintenance of Alternative Path [Begin of Text Proposal: From
C802.16n-11/0050r3] HR-BS and HR-MS
shall store the information of alternative path as the backup in the event of
failure of intermediate station. The information of alternative path is TBD. The HR-MS and the
access station of the alternative path shall store pre-negotiated information
for fast network re-entry after SPOF.] [End of Text Proposal: From C802.16n-11/0050r3] [Begin of Text Proposal: From
C802.16n-rg-11/0029] When the topology is
changed, backup path should be recalculated to maintain its up to date status
and efficiency. Both HR-BS and HR-MS can decide HR-MS’s current backup path is
still relevant or not. If it’s not, HR-BS or HR-MS shall construct a new backup
path according to session 17.2.7.2. 17.2.7.7
Handover to Alternative Path [Begin of Text Proposal: From
C802.16n-rg-11/0029] When HR-MS’s timeout with
its current superordinate node exceed the TIME_OUT threshold, it shall inform
HR-BS of this disruption through DSD-REQ message. This DSD-REQ message is sent
through the backup path. This message also serves as the trigger for nodes in
backup path. Intermediate nodes on the backup path will then mark the corresponding
backup entry in their routing table as currently active and shall use this
entry to relay data from/to HR-BS. The intermediate nodes in
the backup path should reply the DSD-REQ received from its subordinate node
with DSD-RSP message to confirm that switching to backup path has been carried
out. After receiving DSD-RSP message from its superordinate, HR-MS shall
transmit data to HR-BS through the backup path normally. Once HR-BS receives the
DSD-REQ from HR-MS, it shall refresh its topology information and inform
affected HR-MS about the new topology changes.] [End of Text Proposal: From
C802.16n-rg-11/0029] 17.2.7.8
Failure Detection [Begin of Text Proposal: From
C802.16n-11/0050r3] The failure
detection can be performed by the stations around the point of failure and the
reports from the stations around the point of failure may be used for HR-BS’s
decision to establish the path using alternative path information. The
detection procedure and reporting messages is TBD. 17.2.7.9
Fast network re-entry after SPOF [Begin of Text Proposal: From
C802.16n-11/0050r3] Optimized network
re-entry shall be used for accelerating path recovery. Pre-allocated ranging
codes shall be used to achieve contention-free ranging at network re-entry. The
details are TBD. The path recovery could be either initiated by the serving HR-BS or
the HR-MS lost of the connection with HR-network. When the HR-BS initiate the
path recovery, it sends out the control messages to establish the path for the
HR-MS lost of the connection with HR-network, and the access station along the
alternative path prepares for the network re-entry for this HR-MS.] [End of Text Proposal: From
C802.16n-11/0050r3] [Begin of Text Proposal: From C802.16n-11/0028r3] Upon detection of a
failure at the serving BS, FSs shall switch mode and perform network entry
using the most recent configuration information. It shall facilitate fast
network re-entry for SSs obtained from the most recent configuration
information.] [End of Text Proposal: From
C802.16n-11/0028r3] ***** END: PATH MNG ***** |