Conference azur::mcc

5333.0. "How Are MIBs Updated?" by ANGLIN::CLAYTON (Merlin Clayton DTN 445-7217) Tue Jul 13 1993 12:17

A customer asked me a question the other day about updating private MIBs
which never ocurred to me, but needs to be considered.

When updating private MIB definitions that include multiple MIB groups
(a good example is the Xyplex MIBs which include about 13 different groups),
how can MCC update just one MIB group without replacing the entire private 
MIB structure with just the last MIB group compiled?

An possible scenario using the Xyplex MIBs might be as follows:

1. At system setup time, compile and update the MIR with the 9 Xyplex MIB
   groups used to manage Xyplex servers.  These groups include:

	XYPLEX_BOOTCLNT_MIBDEF.TXT;3            XYPLEX_BOOTSRVR_MIBDEF.TXT;3
	XYPLEX_CHAR_MIBDEF.TXT;3                XYPLEX_CHASSIS_MIBDEF.TXT;3
	XYPLEX_DECNET_MIBDEF.TXT;3              XYPLEX_ETHERNET_MIBDEF.TXT;3
	XYPLEX_LAT_MIBDEF.TXT;3			XYPLEX_PRMCLIENT_MIBDEF.TXT;3
	XYPLEX_SYSTEM_MIBDEF.TXT;3

   Each time the MCC compiler is run for one or more of the MIB groups, it
   prompts the user with a message similar to:

   "Do you want to replace existing MIB definition? "

   In order to incrementally add the MIB groups you respond with "No".

   The the compiler prompts with a message similar to:

   "Do you want to augment MIB definition?"

   To this you respond "Yes".

   This sets up the privat Xyplex MIB definition with the various MIB groups
   defined.

2. A month later, Xyplex comes out with a new version of software which 
   includes a new SNMP agent for the server and requires a new MIB definition
   for the System group (XYPLEX_SYSTEM_MIBDEF.TXT by MCC naming conventions).

   So now the user wants to update *JUST* the Xyplex System group for the new
   agent and nothing else.  When he compiles the new system MIB definition,
   he obviously cannot respond with "Yes" to the "Do you want to replace..."
   prompt, because this would replace the entire Xyplex MIB structure with
   just the one being compiled (XYPLEX_SYSTEM_MIBDEF.TXT).

   So then, how does one update just a member of a MIB tree without affecting
   the structure of other groups that are already correctly defined?

Thanks.

Merlin

	If the new Xyplex system group just has additions or changes to current
	objects, then you could chose the "augment" option in MTU and the 
	dictionary will be updated with the new objects. However, if the
	new mib also has deletions, then you need to go into DAP and delete
	the child entity corresponding to the group, and then do an augment.

	Assuming that the child entity for the system group is "system", you
	would have to issue the following DAP commands to delete the group.

	$ manage/tool/dictionary
	DAP> delete class snmp subclass xyplex subclass system

	Hope this helps.

	Rahul.