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SNMP must account for and adjust to incompatibilities between managed devices. Different computers
use different data-representation techniques, which can compromise the ability of SNMP to exchange
information between managed devices.
SNMPv1 is the initial implementation of the SNMP protocol and is described in RFC 1157
(http://www.ietf.org/rfc/rfc1157).
SNMPv1:
Functions within the specifications of the Structure of Management Information (SMI).
Operates over protocols such as User Datagram Protocol (UDP), Internet Protocol (IP), OSI
Connectionless Network Service (CLNS), AppleTalk Datagram-Delivery Protocol (DDP),
and Novell Internet Packet Exchange (IPX).
Is the de facto network-management protocol in the Internet community.
The SMI defines the rules for describing management information by using Abstract Syntax Notation
One (ASN.1). The SNMPv1 SMI is defined in RFC 1155 (http://www.ietf.org/rfc/rfc1155). The SMI
makes three specifications:
ASN.1 data types
SMI-specific data types
SNMP MIB tables
The SNMPv1 SMI specifies that all managed objects must have a subset of associated ASN.1 data types.
Three ASN.1 data types are required:
Name—Serves as the object identifier (object ID).
Syntax—Defines the data type of the object (for example, integer or string). The SMI uses a subset
of the ASN.1 syntax definitions.
Encoding—Describes how information associated with a managed object is formatted as a series
of data items for transmission over the network.
The SNMPv1 SMI specifies the use of many SMI-specific data types, which are divided into two
categories:
Simple data types—Including these three types:
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Integers—A signed integer in the range of -2,147,483,648 to 2,147,483,647.
`
Octet strings—Ordered sequences of zero to 65,535 octets.
`
Object IDs— Come from the set of all object identifiers allocated according to the rules
specified in ASN.1.
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