Cisco 15327 - Manual (Page 369)

22-3
Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 22 Configuring SNMP
SNMP Versions
SNMP Versions
Both the ML-Series card and the ONS 15454 SONET/SDH nodes support SNMP Version 1 (SNMPv1)
and SNMP Version 2c (SNMPv2c), defined as:
• SNMPv1—The Simple Network Management Protocol, a full Internet standard, defined in
RFC 1157.
• SNMPv2c replaces the party-based administrative and security framework of SNMPv2 classic with
the community-string-based administrative framework of SNMPv2c while retaining the bulk
retrieval and imroved error handling of SNMPv2classic. The bulk retrieval mechanism retrieves
tables and large quantities of information, minimizing the number of round-trips required. The
SNMPv2c improved error-handling includes expanded error codes that distinguish different kinds
of error conditions; these conditions are reported through a single error code in SNMPv1. Error
return codes in SNMPv2c report the error type.
SNMPv1 and SNMpv2c have the same security models and levels:
• Level—noAuthNoPriv
• Authentication—community string
• Encryption—none
• Result—Uses a community string match for authentication.
You must configure the SNMP agent to use the SNMP version supported by the management station.
Because an agent can communicate with multiple managers, you can configure the software to support
communications using SNMPv1, and SNMPv2c protocols.
SNMP Manager Functions
The SNMP manager uses information in the MIB to perform the operations described in Table 22-1 .
Table 22-1 SNMP Operations
Operation Description
get-request Retrieves a value from a specific variable.
get-next-request Retrieves a value from a variable within a table. 1
1. With this operation, an SNMP manager does not need to know the exact variable name. A sequential search is performed to
find the needed variable from within a table.
get-bulk-request 2
2. The get-bulk-request command only works with SNMPv2 or later.
Retrieves large blocks of data, such as multiple rows in a table, that would
otherwise require the transmission of many small blocks of data.
get-response Replies to a get-request, get-next-request, or set-request sent by an NMS.
set-request Stores a value in a specific variable.
trap An unsolicited message sent by an SNMP agent to an SNMP manager when some
event has occurred.