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Re: [STDS-802-16] [802.16n] [MM] Proposed harmonized text for Path management



Hi Hoang and all,

 

I have some comments and would like to seek clarification on 17.2.7.4. See below:

 

17.2.7.4 Path Management when HR-BS and HR-MS change role

An HR-BS changing its role as HR-RS may select alternative path for subordinate HR-MS in the event of disruption.

[WL] It seems that there are multiple alternative paths prepared for a HR-MS, and HR-BS selects one in the event of disruption. Is that correct?

The HR-BS may switch to the alternative path.

[WL] I think HR-MS should be the station switching to use the alternative path and perform fast network re-entry, and the signaling is done by the HR-BS.

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.

[WL] Two issues here: (1) It is not clear which station selects the alternative path. For consistency, I propose that the signaling to be done by the serving HR-BS. (2) According to the SRD, alternative paths are used for fast network recovery in event of disruption. Returning to HR-MS from RS mode has nothing to do with disruptions, so alternative paths are ill-defined for this purpose.

 

 

Regards,

Wai Leong

 

From: Hoang Vinh Dien [mailto:hvdien@NICT.COM.SG]
Sent: Thursday, May 05, 2011 10:23 AM
To: STDS-802-16@LISTSERV.IEEE.ORG
Subject: [STDS-802-16] [802.16n] [MM] Proposed harmonized text for Path management

 

Dear All,

 

Following the teleconference discussion, I had revised the harmonized text for the path management in three points:

1. Make clear that Alternative path is determined by the HR-BS

2. Remove the access station, replace by superordinate

 

Changes are in the red in the text below. The track-change document can be found in the RG upload directory, file name: C80216n-rg-11_0059r2.doc.

 

Please have your comments on these.

 

Thanks and best regards,

Hoang Vinh Dien

 

 

 

[-------------------------------------------------Begin of Text Proposal----------------------------------------------------]

17.2.7 Path Discovery and Management

 

17.2.7.1 Alternative Path Definition

An alternative path is used for fast network recovery to a HR-MS in the event of disruption, e.g. when the serving HR-RS or HR-BS fails. In normal operation, there are no active connections on any alternative path. The alternative path will only be activated when a single point of failure is detected.

An alternative path is a link or a list of continuous links between an HR-MS and the serving HR-BS, or an alternative HR-BS. An alternative path is determined by the serving HR-BS.

17.2.7.2 Alternative Path Management

 

Alternative path management consists of its establishment and maintenance, and the signaling for fast network recovery when switching to the alternative path.

 

The stations involved in the alternative path management are the HR-MS, its superordinate and serving HR-BS, an alternative superordinate and an alternative HR-BS.

 

17.2.7.2.1 Alternative Path Establishment

      Serving HR-BS

     Choose an alternative path including mode change for of its subordinate HR-MSs

     The algorithm and criteria for choosing the alternative path: TBD

     Store alternative path information

     Inform HR-MS of the path and path information

      Superordinate of HR-MS

     TBD

      HR-MS

     Store Alternative Superordinate

     Store fast network re-entry information

      Alternative HR-BS (may be different from serving HR-BS)

     Store alternative path information

     Store HR-MS information

      Alternative Superordinate

     Store HR-MS information

17.2.7.2.2 Maintenance of Alternative Path

       Serving HR-BS

     Whenever an alternative path is invalid or better alternative path is available

     Update alternative path information for all HR-MS

     Inform HR-MS of the path and path information

      Superordinate of HR-MS

     TBD

      HR-MS

     Monitor alternative access link

     Inform serving HR-BS  if alternative access link is unavailable

      Alternative HR-BS (may be different from serving HR-BS)

     TBD

      Alternative Superordinate

     Remove when alternative path is not needed

17.2.7.2.3 Failure Detection

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.

17.2.7.3 Switching to Alternative Path after SPOF

      HR-MS

     Perform fast network re-entry to alternative superordinate using stored information

     Inform serving HR-BS

      Alternative HR-BS (may be different from serving HR-BS)

     Allow network re-entry

      Alternative Superordinate

     Allow network re-entry

 

17.2.7.4 Path Management when HR-BS and HR-MS change role

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 may switch to the alternative path.

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.

 

[-------------------------------------------------End of Text Proposal----------------------------------------------------]