Essential SNMP, 2nd Edition

A Closer Look at MIB-II

MIB-II is a very important management group because every device that supports SNMP must also support MIB-II. Therefore, we will use objects from MIB-II in our examples throughout this book. We won't go into detail about every object in the MIB; we'll simply define the subtrees. The section of RFC1213-MIB that defines the base OIDs for the mib-2 subtree looks like this:

mib-2        OBJECT IDENTIFIER ::= { mgmt 1 }
system       OBJECT IDENTIFIER ::= { mib-2 1 }
interfaces   OBJECT IDENTIFIER ::= { mib-2 2 }
at           OBJECT IDENTIFIER ::= { mib-2 3 }
ip           OBJECT IDENTIFIER ::= { mib-2 4 }
icmp         OBJECT IDENTIFIER ::= { mib-2 5 }
tcp          OBJECT IDENTIFIER ::= { mib-2 6 }
udp          OBJECT IDENTIFIER ::= { mib-2 7 }
egp          OBJECT IDENTIFIER ::= { mib-2 8 }
transmission OBJECT IDENTIFIER ::= { mib-2 10 }
snmp         OBJECT IDENTIFIER ::= { mib-2 11 }

mib-2 is defined as iso.org.dod.internet.mgmt.1, or 1.3.6.1.2.1. From here, we can see that the system group is mib-2 1, or 1.3.6.1.2.1.1, and so on. Figure 2-4 shows the MIB-II subtree of the mgmt branch.

Figure 2-4. MIB-II subtree

Table 2-5 briefly describes each management group defined in MIB-II. We don't go into great detail about each group since you can pull down RFC 1213 and read the MIB yourself.

Table 2-5. Brief description of the MIB-II groups

Subtree name	OID	Description
system	1.3.6.1.2.1.1	Defines a list of objects that pertain to system operation, ...