Simple Network Management Protocol (SNMP) was designed as an answer to the communication problems brought about by different network platforms, protocols, and proprietary network operating systems. Although designed as a temporary solution, it has become the network management protocol of choice.
SNMP exchanges network information through messages known as PDU (protocol data units). From a high-level perspective, the PDU is seen as an object containing variables consisting of both titles and values. SNMP uses five types of PDUs to monitor a network: two deal with setting terminal data, two deal with reading terminal data, and one, the trap, is used for monitoring network events such as start-ups and shut-downs.
The greatest advantage in using SNMP is its simple design. This makes it easy to implement on a large network, for it neither takes a long time to set up nor puts a great deal of stress on the network. In addition, its easy-to-use features allow you to quickly program variables you would like to have monitored in your network. The expandability of SNMP continues to be an asset in the ever more complicated Intranet and Internet networking environments of today’s business world.
As a result of its popularity, almost all major vendors of Internet hardware design their products to support SNMP.
The SNMP Public MIB variables available in NPM/IP are:
System |
Provides generic configuration information, such as device description, agent’s hardware and software, how long ago the agent was started/re-started, device name, physical location, and device services |
IP (G) |
Contains information on the IP subsystem of a managed node such as whether the device is acting as a router or a host, default TTL for packets, datagrams delivered, discarded, timeout value and so forth |
ICMP (G) |
Uses counters to keep track of the message types generated and received by this local ICMP entity including received, sent, received in error or not sent due to error |
UDP (G) |
Provides four counters and a table for datagram delivery, destined for unknown ports, discarded due to format errors, and sent from UDP group |
TCP (G) |
Identifies the retransmission algorithm, maximum/minimum retransmission timeouts, and number of active/passive opens, resets, connections, etc. |
Interface (G) |
Contains generic information on the interface layers such as- interface description, interface type, MTU size, transmission rate, media specific address etc. |
Route Table |
Contains an entry for each route known to the entity. |
The SNMP private MIB variables available in NPM/IP are:
IBM2216 |
Contains the table in the MIB module for objects used to manage the IBM 2216 device. The table contains information about PCI adapters in the IBM 2216 equipment. |
CISCO CIP |
Describes the MIB module for objects used to manage the CICSO Mainframe Channel Connection cards. The values can be accessed to determine the general state of the CMCC. |
CISCO
CIP |
Provides information on the MIB module for objects used to manage the Cisco Mainframe Channel Connection (CMCC) cards. The Channel table contains a list of objects pertaining to the channel or daughter board on the CMCC card. Click an Index hyperlink in the CISCO CIP screen to access this subscreen. |
CISCO
|
Contains the list of objects pertaining to each host connection. Click an Index hyperlink in the CISCO CIP Channel subscreen to access this subscreen. |
TN3270 Global |
Describes the MIB module for objects used to manage the TN3270 server. |
TN3270 PU Table (subscreen of TN3270 Global) |
Contains the table in the MIB module for objects used to manage the TN3270 server. The PU table holds objects that describe the PU configuration parameters not defined in the NAU MIB, APPN MIB or DLUR MIB. Click an Index hyperlink in TN3270 Global to access this subscreen. |
TN3270 LU Table (subscreen of TN3270 PU Table) |
Contains the table in the MIB module for objects used to manage the TN3270 server. The LU table helps map LU to client IP address/port. Click an Index hyperlink in the TN3270 LU Table to access this subscreen. |
TN3270E Config |
Contains the Configuration table in the MIB module for objects used to manage the TN3270E server. The Configuration table contains information about the general state of the server. |
TN3270E |
Contains a set of statistics concerning global TN3270E server performance. An entry can be global with respect to a single TN3270E server or it can be specified at the port level. |
TN3270E TCP |
Contains the table in the MIB module for objects used to manage the TN3270E server. This table has an entry for each TN3270(E) client connection that is active at a TN3270E server. |
TN3270E SNA Server Map Table (subscreen of TN3270E Statistics and TN3270E TCP) |
Contains the table in the MIB module for objects used to manage the TN3270E server. This table defines the mapping of an SLUName to a PLUName. |
OSA Express (G) |
Contains one entry per OSA Express device interface. |
OSA Performance (G) |
Provides performance information per each LPAR's utilization of an OSA-Express adapter. |
OSA Ethernet (G) |
Represents the Ethernet ports associated with the OSA Express Channel Table entries for Ethernet adapters. |
To access SNMP MIB Browser, perform the following steps:
1. Click the SNMP tab from anywhere in the application. The SNMP Browser main screen displays in a second browser window. You may maximize or change the size of the new browser window to suit your preference.
2. Enter the IP address of an SNMP-capable device in the text box labeled Address. The MIBs on this address are interrogated.
3. If desired, change the community name by entering it at the text box for Community Name. The community name is password-protected and your entry will display in asterisks, so be sure to type carefully.
The default community name is “public”. Many installations change the name for security purposes. Only a community name with read authority is required for NPM/IP.
4. Select the MIB type desired from the MIB Type drop-down list box. A (G) displays after the MIB type if graphs are available for that type.
You may want to start with the System MIB to make sure you have access to the device.
Note: To view system group information for an address, enter the IP address in the Address box and then select System as the MIB Type. The device must have SNMP capability.
1. Do one or more of the following:
· Click the View Changes checkbox to view the delta from one time interval to the next.
· Click the View Graphs checkbox to view any graphs that are available.
· Click the Graphs on Top checkbox to view graphs at the top of the page and the tabular MIB fields at the bottom. Or to reverse the display and view the tabular MIB fields at the top of the page and the graphs at the bottom, leave the Graphs on Top checkbox unchecked.
In either case, the View Graphs checkbox must also be checked in order to display graphs.
You can quickly scroll to the bottom of the page to view the other format (Graph or MIB fields) by clicking the Graphs or Report link at the top of the screen.
2. Click the Get MIB button. A message appears on the second frame in the SNMP window indicating that the search for information has started. Please wait until either the desired MIB information appears on the screen (in the second frame) or an error message appears. For some MIBs, this may take a few minutes.
3. To view other MIBs for the selected address, select a different MIB type from the MIB Type drop-down list and click the Get MIB button.
4. When you have finished viewing the MIBs, close the SNMP MIB Browser window by clicking the "x" close box in the upper right corner of the window.
You are returned to the previous window and the navigation bar displays, from which you can access other NPM/IP functions.