Subject: [Capwap] The changs log of CAPWAP Dot11 MIB version 03

From: shiyang 00338 <[email-masked]>
Date: Tue, 03 Mar 2009 21:58:44 +0800

Hi,

   The CAPWAP Dot11 MIB version 03 was published, and most changes are to
   close issues found by Dan. We also modified some issue found ourself.

   T1.  T4.  In order for ifIndex to be used as a common handler for the  
   CAPWAP MIB and for the interface specific MIB modules like a dot11     
   MIB from IEEE one needs to ensure that the same numbering scheme and   
   mapping is used by all MIB modules, and that it behaves identically    
   for events like interface card swapping, reset or power loss.  I do    
   not see how this can happen, I am not sure that this is possible at    

Shi, et al.             Expires September 4, 2009              [Page 23]  
                                                                         
Internet-Draft         CAPWAP Protocol Binding MIB            March 2009  

   all, and in any case there is no text in the document that explains    
   this mechanism.                                                        
                                                                          
   --------------------------------------------------------------         
                                                                          
   In the Capwap Digest, Vol 39, Issue 4, we gave the text to explain a   
   mechanism that preserves the values of ifIndex, Request mailing list   
   to confirm it.                                                         
                                                                          
   In the section of "Relationship to the IF-MIB", add text:              
                                                                          
   Also, the system (AC) MUST have a mechanism that preserves the values  
   of ifIndex of 'WLAN Service Interface' ifType in the ifTable at AC     
   reboot.                                                                
                                                                          
   Also, the system (AC) MUST have a mechanism that preserves the values  
   of ifIndex of 'WLAN BSS Interface' ifType in the ifTable at AC         
   reboot.                                                                
                                                                          
   T2.  Is the WLAN Service interface described in Section 7.2 modeled    
   by capwapDot11WlanConfigTable?  If so please say it and make this      
   clear by using a more explicit naming convention.  The model here is   
   not clear to me.  On one hand you say 'the interface SHOULD be         
   modeled as an ifEntry ...'  Why only a SHOULD and not a MUST?  What    
   is the procedure for the manager?  Is he looking for all 802.11        
   interfaces on the AC and then creates manually a WLAN Service entry    
   in the table for each?  What if the ifNumber does not correspond to a  
   802.11 interface?  What if the 802.11 interface disappears?            
                                                                          
   -----------------------------------------------------------------      
                                                                          
   1) The "WLAN Service interface" is modeled by                          
   capwapDot11WlanConfigTable, and capwapDot11WlanConfigTable is rename   
   as capwapDot11WlanTable.                                               
                                                                          
   2) Yes, the the interface MUST be modeled as an ifEntry, not SHOULD    
   be                                                                     
                                                                          
   3) What is the procedure for the manager?  Is he looking for all       
   802.11 interfaces on the AC and then creates manually a WLAN Service   
   entry in the table for each?                                           
                                                                          
   Please refer to the section of Example of CAPWAP-DOT11-MIB Module      
   Usage (the section is updated in the new version).                     
                                                                          
   The creation operation of a row object on capwapDot11WlanTable would   
   trigger system to create "WLAN service Interface", and it does not     
   require operator to manually create a "WLAN service Interface".        

Shi, et al.             Expires September 4, 2009              [Page 24]  
                                                                         
Internet-Draft         CAPWAP Protocol Binding MIB            March 2009  

   In the section of "Relationship to the IF-MIB", add text:              
                                                                          
   Also, the system (AC) MUST have a mechanism that preserves the values  
   of ifIndex of 'WLAN Service Interface' ifType in the ifTable at AC     
   reboot.                                                                
                                                                          
   T3.  What 'could be always enabled' means for ifAdminStatus and        
   ifOperStatus in the WLAN Service Interface table?  Either change this  
   to MUST or explain in what cases these should be other than enabled.   
                                                                          
   --------------------------------------------------------------         
                                                                          
   The section for interpration of specific MIB objects in the iftable    
   was removed in the new version.  Reader could refer to RFC2863         
                                                                          
   T4.  What does the statement that 'the other objects such as           
   ifInOctets ... are unused' relative to the VLAN Service interface      
   mean?  Counters are always zero?                                       
                                                                          
   --------------------------------------------------------------         
                                                                          
   The section for interpration of specific MIB objects in the iftable    
   was removed in the new version.  Reader could refer to RFC2863         
                                                                          
   T5.  In 7.4 - does the text mean that the manager can reuse objects    
   from the IEEE 802.11 MIB modules, or that values of these objects are  
   being duplicates in this MIB module? (why?  Which ones?)  In any case  
   the IEEE 802.11 standard that defines these objects must be a          
   Normative Reference for this document.                                 
                                                                          
   -----------------------------------------------------------------      
                                                                          
   Yes                                                                    
                                                                          
   1)the text mean that the manager can reuse objects from the IEEE       
   802.11 MIB modules, and the section of "Mechanism of Reusing Wireless  
   Binding MIB Module" give explain to it.                                
                                                                          
   2) also, add one text of "The CAPWAP-DOT11-MIB module does not         
   duplicate those objects in the MIB module of IEEE 802.11 standard."    
   in the section of "7.4.  Relationship to MIB Module in IEEE 802.11     
   Standard"                                                              
                                                                          
   3) yes, IEEE 802.11 standard was added as a Normative Reference.       
                                                                          
   T6.  The RFCs that define all MIB modules required for IMPORTSs must   
   be Normative References to this document.                              

                                                                          
Shi, et al.             Expires September 4, 2009              [Page 25]  
                                                                         
Internet-Draft         CAPWAP Protocol Binding MIB            March 2009  

   -----------------------------------------------------------------      
                                                                          
   add reference to RFC3411 in the section of "MIB modules required for   
   IMPORTS", add "SNMP-FRAMEWORK-MIB [RFC3411],"                          
                                                                          
   T7.  The value of the object capwapBaseWTPId in the example is the     
   string '12345678' not the integer 12345678                             
                                                                          
   -----------------------------------------------------------------      
                                                                          
   Yes, it is change into '12345678'                                      
                                                                          
   T8.  The names of the objects in the capwapDot11WlanConfigTable are    
   not consistent (similar prefix) to capwapDot11WlanConfigEntry.         
                                                                          
   ---------------------------------------------------------              
                                                                          
   Yes, they are changed with:                                            
                                                                          
   CapwapDot11WlanEntry ::=                                               
       SEQUENCE {                                                         
         capwapDot11WlanId                 CapwapDot11WlanIdTC,           
         capwapDot11WlanServiceIfIndex     InterfaceIndex,                
         capwapDot11WlanMacType            CapwapBaseMacTypeTC,           
         capwapDot11WlanTunnelMode         CapwapBaseTunnelModeTC,        
         capwapDot11WlanRowStatus          RowStatus                      
       }                                                                  
                                                                          
   T9.  The names of the objects in the capwapDot11WlanBindTable are not  
   consistent (similar prefix) to capwapDot11WlanBindEntry.               
                                                                          
   ---------------------------------------------------------              
                                                                          
   Yes, they are changed with:                                            
                                                                          
   CapwapDot11WlanBindEntry ::=                                           
       SEQUENCE {                                                         
         capwapDot11WlanBindBssIfIndex      InterfaceIndex,               
         capwapDot11WlanBindBssRowStatus    RowStatus                     
       }                                                                  
                                                                          
   T10.  What does 'Bits are exclusive for each other for a specific      
   WLAN Id' mean for capwapDot11WlanTunnelMode?  That only one tunnel     
   mode can be configured (one bit set)?  I assume this does not include  
   the bit unused(0).  What happens if the manager sets more than one     
   bit, ore no bit, or unused(0) - how does the agent behave in this      
   case?                                                                  

                                                                          
Shi, et al.             Expires September 4, 2009              [Page 26]  
                                                                         
Internet-Draft         CAPWAP Protocol Binding MIB            March 2009  

   -----------------------------------------------------------------      
                                                                          
   1) Yes, unused(0) is removed.                                          
                                                                          
   2) The description is updated with:                                    
                                                                          
   Bits are exclusive with each other for a specific WLAN Id, and only    
   one tunnel mode could be configured.  If operator set more than one    
   bit, the value of the Response-PDU's error-status field is set to      
   `wrongValue', and the value of its error-index field is set to the     
   index of the failed variable binding."                                 
                                                                          
   T11.  What is the persistency of the capwapDot11WlanTunnelMode at      
   agent reboot?  Is the whole table persistent at agent reboot?          
                                                                          
   -----------------------------------------------------------------      
                                                                          
   Yes, it should be whole table persistent instead of previous           
   statement "Values of all read-create objects in this table are         
   persistent at restart/reboot."                                         
                                                                          
   T12.  I do not understand how does row creation in the                 
   capwapDot11WlanBindTable work.  It is indexed by ifIndex and           
   capwapDot11WlanId.  The only visible object in this table except       
   RowStatus is capwapDot11WlanBssIfIndex which is read-only and the      
   description says that 'it is the same interface as identified by the   
   same value of ifIndex.  But the manager cannot read its value until    
   the row exists.  How does the manager know its value in order to       
   create the row in the table?                                           
                                                                          
   ----------------------------------------------------------------       
                                                                          
   The old description would lead to misunderstanding when it says "The   
   interface identified by a particular value of this index is the same   
   interface as identified by the same value of ifIndex".  In fact, the   
   ifIndex here is not a ifIndex in the INDEX { ifIndex (it is a          
   "Wireless virtual radio interface), capwapDot11WlanId }, while it is   
   a "WLAN "WLAN BSS Interface".                                          
                                                                          
   To clarify it, the following text is added to the description of       
   capwapDot11WlanBindBssIfIndex:                                         
                                                                          
   The ifIndex here is for an interface of 'WLAN BSS Interface'.  For a   
   WLAN configuration on a radio, an interface of 'WLAN BSS Interface'    
   will correspond to it.  The creation operation of a row object on the  
   capwapDot11WlanBindTable would trigger AC system to automatically      
   create a 'WLAN BSS Interface' and it is identified by ifIndex.  It     
   does not require operator to manually create a 'WLAN BSS Interface'.   

Shi, et al.             Expires September 4, 2009              [Page 27]  
                                                                         
Internet-Draft         CAPWAP Protocol Binding MIB            March 2009  

   For the table of capwapDot11WlanBindTable, the description is updated  
   with the following text:                                               
                                                                          
   A table of objects that configure which WLAN (identified by            
   capwapDot11WlanId) will be provided on which 'WTP Virtual Radio        
   Interface' (identified by ifIndex) Also, display and control the       
   mapping relationship between interface of 'WTP Virtual Radio           
   Interface' interface and interface of 'WLAN BSS Interface'.  The PHY   
   address for interface of 'WTP Virtual Radio Interface' ifType will be  
   base BSSID address for PHY radio.                                      
                                                                          
   Values of all bjects in this table are persistent at restart/reboot.   
                                                                          
   For the table of capwapDot11WlanBindEntry, the description is updated  
   with the following text:                                               
                                                                          
   A set of objects that display the mapping relationship between         
   interface of 'WTP Virtual Radio Interface' and interface of 'WLAN BSS  
   Interface'.  The Index object ifIndex is a ifIndex of a 'WTP Virtual   
   Radio Interface'.                                                      
                                                                          
   T13.  Is the capwapDot11WlanBindTable persistent at agent reboot?      
                                                                          
   -----------------------------------------------------------------      
                                                                          
   Yes, The whole table is persistent at restart/reboot.                  
                                                                          
   E1.  Not all acronyms are expanded at first occurrence - e.g.  WTP     
                                                                          
   -----------------------------------------------------------------      
                                                                          
   The Terminology section is updated with more Terminology such as       
   CAPWAP,WTP,AC, Wireless Binding,Split and Local MAC and so on.         
                                                                          
   E2.  Please avoid using the construct 'the MIBs' (e.g. in Section 5).  
   s/the MIBs/the MIB modules/                                            
                                                                          
   -----------------------------------------------------------------      
                                                                          
   use either "MIB module" or "MIB modules" in the document               
                                                                          
   E3.  There is no need to include sections 6.1 and 6.2, they provide    
   no new or specific information for this MIB module.                    
                                                                          
   ----------------------------------------------------------------       
                                                                          
   Yes, they were removed                                                 

                                                                          
Shi, et al.             Expires September 4, 2009              [Page 28]  
                                                                         
Internet-Draft         CAPWAP Protocol Binding MIB            March 2009  

   E4.  I suggest for this document to be verified by a native English    
   speaker for English spelling and grammar.                              
                                                                          
   E5. ifIndex, ifDescr, ifName, ifAlias in the WLAN Service Interface    
   and WLAN BSS Interface table contain no specific information, I        
   suggest to just mention that they are used as per RFC 2863             
                                                                          
   --------------------------------------------------------------         
                                                                          
   The section for interpration of specific MIB objects in the iftable    
   was removed in the new version.  Reader could refer to RFC2863         
                                                                          
Other changes made by authors:                                            
1) reorganized the section of overview, and divided it into the           
following sub sections:                                                   
   5.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  5  
     5.1.  Requirements and Constraints . . . . . . . . . . . . . . .  5  
     5.2.  Mechanism of Reusing Wireless Binding MIB Module . . . . .  5  
                                                                          
2) Update some words in the section of" Example of CAPWAP-DOT11-MIB       
Module Usage, especially explain how interfaces of                        
"WLAN service Interface" and "WLAN BSS Interface" are created.            
                                                                          
3) Modify the value scope of CapwapDot11WlanIdTC from (1, 16) to          
(1, 512), and description of it.                                          

_________________________________________________________________
To unsubscribe or modify your subscription options, please visit:
http://lists.frascone.com/mailman/listinfo/capwap

Archives: http://lists.frascone.com/pipermail/capwap

---

From: "David Harrington" <[email-masked]>
Date: Tue, 3 Mar 2009 18:05:00 -0500

Hi,

I believe the interfaces-mib explicitly allows the ifIndex to not be
preserved across reboot. That was a conscious decision of the WG that
did the update to the interfaces-mib (despite the advice of those,
like keith McLoughrie who explained that was a really really bad
decision). But the WG did this because it is very difficult for
devices to be sure that the interfaces were not physically reordered
(e.g., removal or insertion or moving of a board in a chassis) while
the device was powered off during the reboot.

The ifName (if I remember correctly) was added to allow remote systems
(such as an NMS) to correlate new ifIndex assignments to pre-boot
assignments.

I think it would be inappropriate to require non-changing ifIndexes.

dbh

> -----Original Message-----
> From: shiyang 00338 [mailto:[email-masked]] 
> Sent: Tuesday, March 03, 2009 8:59 AM
> To: [email-masked]
> Cc: [email-masked]; [email-masked]
> Subject: [Capwap] The changs log of CAPWAP Dot11 MIB version 03
> 
> 
>    Hi,
> 
> >                                                               
> ---      
> >                                                               
> ---      
> >                                                               
> ---      
> ---      
> >                                                               
> ---      
> ---      
> --       
> >                                                               
> ---      
> ---      
> ---      
> --       
> >