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Conference azur::mcc

Title:DECmcc user notes file. Does not replace IPMT.
Notice:Use IPMT for problems. Newsletter location in note 6187
Moderator:TAEC::BEROUD
Created:Mon Aug 21 1989
Last Modified:Wed Jun 04 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:6497
Total number of notes:27359

2012.0. "Registration of SNMP nodes using iconic map" by TAEC::HARPER (John Harper, DTN 830 3647) Tue Dec 31 1991 11:54

    Another problem to which the answer may exist buried somewhere in the
    documentation...
    
    I'd like to register an SNMP node, so that I can do the iconic
    equivalent of:
    
    	show snmp pmaxak.lkg.dec.com  [which works just fine]
    
    When I try this, I get told something to the effect of "only
    partially registered, entity doesn't exist".  When I then try to look
    into it, I get FIVE message windows (all on top of each other) telling
    me that the internet address isn't registered.
    
    I'm running on Ultrix, with the latest T1.2.4 kit.
    
    Obviously FCL is using the standard TCP/IP interface and is using
    D(omain)NS.  Questions...
    
    1.	Is there a way to get registration to go out to DNS?  This
    	is surely what one woudl expect, especially on an Ultrix
    	system!
    
    2.	I guess the five separate message windows is a bug?
    
    	John
T.RTitleUserPersonal
Name
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2012.1QAR 2050TOOK::MINTZErik Mintz, DECmcc DevelopmentTue Jan 07 1992 11:162
Entered as QAR 2050 in mcc_internal

2012.2re:.0BARREL::LEMMONFri Jan 17 1992 12:0658
    First let me explain what is going on, then I will get into what could 
    be done to make the interface more user friendly.

    The SNMP entity has three identifier attributes

    	registered name   (e.g., local_ns:.mcczip)
    	name	  	  (e.g., mcczip.lkg.dec.com)
        address	   	  (e.g., 16.20.144.58)
    	
    Partial registration occurs if the name or address field is not
    entered, or the SNMP entity is not reachable.   There are other
    conditions that cause partial registration to occur but that 
    isn't important for this discussion.  

    The iconic map is domain based, which means 

    	a.  the global entity must be registered
        b.  The identifier used for the register directive (fullname datatype)
    	    is used to identify the member.

    Now lets say you add a snmp entity to the map and it is only partially
    registered.   When you lookinto the entity the Iconic Map issues

       for each child class of snmp that DYNAMIC = FALSE
       {
    	    SHOW SNMP NS:.xxx <child> * ALL IDENTIFIERS
       	    if error 
    		display error message box      
    	    else 
    	        display child in map window
       }

    The SNMP am will return the "partially registered" error message for each
    child class.  From your note I gather you already realize that this is
    how thinks work but A little background info never hurts.  

    Now to answer your question...  The SNMP team and REGISTRATION FM 
    team are currently investigating how to modify the REGISTER SNMP 
    operation so that the internet name and address are made available to the 
    SNMP access module when a partial registration occurs.   That is, if either of 
    these arguments are entered, they will be stored in the mir in such a way the 
    SNMP am will be able to translate the fullname passed from the 
    iconic map, or fcl, into the internet name or address.     This, hopefully,
    will get into v1.2. 

    Now, why do you see error boxes?  The Iconic Map has no knowledge 
    that the error condition being returned for each of the show identifier 
    operations are related. It is possible that another MM may 
    augment the SNMP entity, adding a new child entity with a show identifiers 
    directive.  The function provided by this mm may not need the internet name
    or address, hence the show identifier would return a success. 

    We can probably come up with a better way of displaying the error messages
    instead of blasting them all on top of each other.  I will add this to
    the wish list.


    
2012.3Everything you wanted to know about registering snmp global entities ...DANZO::CARRThu Feb 06 1992 18:16129
Here's my best attempt at shedding some light on a very confusing area.  This
will also be posted as the answer to internal qar 2050 and incorporated into
the v1.2 snmp am use guide.

Dan




                      Registering SNMP Global Entities
                      ================================

	Registered snmp entity identifiers may exist in two places, the DECmcc 
MIR and the Domain Name Server DNS (or local host database), see figure 1.  


	DECmcc MIR                                   D(omain)NS
 ==============================================================================
 Registered Name = ETHRFX_NS:.hostname    |
 (Internet) Name = hostname               |    (Internet) Name = hostname
      IP Address = 16.126.16.57           |         IP Address = 16.126.16.57
 ==============================================================================

	Figure 1.  SNMP identifiers in MIR and Domain Name Server


	The REGISTER directive provides the following options for snmp 
entities,

	REGISTER SNMP R_name [SYNONYM = I_name], [ADDRESS = IP_addr]

where 

	R_name is the Registered name 
	I_name is the Internet host name 
	IP_addr is the dot notation ip address.  

	While neither the Internet host name nor IP address arguments are 
required, one or  the other must be supplied for an snmp entity to be fully 
registered.  In addition, for full registration the entity must be reachable
via either  ICMP Echo (PING) or SNMP (get PDU).  Fully registered SNMP entities
have all three identifiers in the DECmcc MIR.  

	Whenever possible, it is desireable to provide the Registered name
and Internet host name when registering snmp global entities and allow the SNMP
Access Module to obtain the IP Address.   The SNMP Access Module tries to
obtain the entity's IP address from the D(omain)NS using the Internet host 
name and the gethostbyname() function.  

	If the Internet host name is unknown or the entity being registered 
has no corresponding entry in the D(omain)NS, the IP address argument  is
provided to allow registration of those entities.  Note that the SNMP AM will
still try to obtain an Internet host name from the D(omain)NS via the
gethostbyaddress() function if no Internet host name has been provided.  If an
Internet host name can not be obtained, the entity will be marked as partially 
registered. (See section  below on partial registration).  Subsequent access
to this partially registered entity is possible if the IP address provided was 
valid.

	Providing both Internet host name and IP address is not necessary 
since the SNMP Access Module can obtain one of these identifiers given the
other.  If both are provided, the SNMP AM uses the Internet host name to obtain
the IP address from the D(omain)NS via the gethostbyname() function. If the
address returned from the D(omain)NS differs from the address supplied, an
exception is generated  (Address argument differs from the address stored in
the Domain Name Server or local host table) and the entity is partially 
registered (See section below on partial registration).  Subsequent operations
will use the IP address returned from the D(omain)NS and the address 
supplied on registration will be ignored.

Partial Registration
====================

	For partially registered  SNMP entities the DECmcc MIR always contains
at least the  Registered name, and may contain either the Internet host name or
the IP address or both.  Partially registered entities can be accessed if the
SNMP Access Module can obtain an IP address either from the D(omain)NS or
from the DECmcc MIR.

	Table 1 below shows the results of providing different combinations of
identifiers when the entity is being registered.  Entries in the column marked 
"In D(omain)NS" apply to the results of a gethostbyname() or
gethostbyaddress() function.  Entries in the "Entity Rechable" column indicate
whether the entity responded to an ICMP echo or SNMP get pdu.  The "Result"
column shows registration status and identifiers contained in the DECmcc MIR.


 Idents Provided                         Entity          
 on Register          In D(omain)NS     Reachable       Result    
===============================================================================

R_name                   n/a             n/a            Partial Registration
                                                        No internet name or
                                                        or ip addr specified.
                                                        Only R_name in MIR.

R_name,I_name             Y               Y             Full Registration. All
                                                        idents in MIR.

R_name,I_name             Y               N             Partial Registration.
                                                        Entity not reachable.
                                                        All idents in MIR.

R_name,I_name             N              n/a            Partial Registration.
                                                        No such entity, Only
                                                        R_name in MIR.

R_name,IP_addr            Y              Y              Full Registration. All
                                                        idents in MIR.

R_name,IP_addr            Y              N              Partial Registration.
                                                        Entity not reachable.
                                                        All idents in MIR.

R_name,IP_addr            N              Y              Partial Registration.
                                                        No Internet name.
                                                        R_name and IP_addr
                                                        in MIR. 

R_name,IP_addr            N              N              Partial Registration.
                                                        Entity not reachable.
                                                        R_name and IP_addr
                                                        in MIR. 
===============================================================================

		Table 1. Registration results.


2012.4Minor correction ...DANZO::CARRThu Feb 06 1992 19:0716

	Providing both Internet host name and IP address is not necessary 
since the SNMP Access Module can obtain one of these identifiers given the
other.  If both are provided, the SNMP AM uses the Internet host name to obtain
the IP address from the D(omain)NS via the gethostbyname() function. If the
address returned from the D(omain)NS differs from the address supplied, an
exception is generated  (Address argument differs from the address stored in
the Domain Name Server or local host table) and the entity is partially 
registered (See section below on partial registration).  Subsequent operations
will use the IP address returned from the D(omain)NS and the address 
supplied on registration will be ignored.

	Actually, subsequent operations are not possible in this case until 
        the correct ip address is provided since the only identifier in the MIR is
	the registered name.