t should always be implemented, deprecated should be implemented but it will become outdated, and obsolete is used when the object is outdated. DESCRIPTION: A description on the object can be given after this tag. Example: address OBJECT-TYPE SYNTAX IpAddress MAX-ACCESS read-write STATUS current DESCRIPTION "Address of the switch" : = { MIB 1} 2. The fields that appear in the object definition of leaf objects are: OBJECT IDENTIFIER: It is used to define a nonleaf object. In the example we discussed, "Info" object falls in this category. Example: Info OBJECT IDENTIFIER: = { MIB 1 } OBJECT-IDENTITY: This tag provides an alternate method to define nonleaf objects. It uses some of the tags when defining leaf objects in creating the definition. Example: OBJECT-IDENTITY STATUS current Fundamentals of EMS, NMS and OSS/BSS DESCRIPTION "Scalar Objects for switch are registered under this object" MIB 1 } 3. The fields that appear in table definition are: INDEX: This tag is used to specify the index of the table or the col- umn/group of columns that will act as the unique identifier for rows in the table. SEQUENCE: The columns in the table can be grouped into a sequence using this tag. Example of table definition using "Routing" shown in Figure 15.4: RowEntries : : = SEQUENCE { dest INTEGER, next INTEGER Comment: Now the rows in the table are defined Routin OBJECT-TYPE SYNTAX SEQUENCE OF RowEntries MAX-ACCESS nonaccessible STATUS current DESCRIPTION "Routing table for the switch" : = { MIB 1} Comment: Now routing table has been defined REntry OBJECT-TYPE SYNTAX RowEntries MAX-ACCESS nonaccessible STATUS current DESCRIPTION "An entry specifying a route" INDEX { dest } Routing 1 } Comment: Now individual entries and index for table is defined Comment: Finally dest and next needs to be defined like scalar objects except that these scalars are associated to the routing table and not directly to MIB. 4. Other fields include: NOTIFICATION-TYPE: This tag is used to define notifications. In SNMP context a notification type is used 