Cisco Systems Dial NMS User Manual
Task 3Using MRTG to Monitor and Graph Traffic Loads
About Selecting Dial OIDs
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Basic Dial NMS Implementation Guide
For each OID referenced in the configuration file, MRTG creates the following graphs:
Daily graph—5 minute average data points with approximately 33 hours of data presented.
Weekly graph—30 minute average data points with approximately 8 days of data presented.
Monthly graph—2 hour average data points with approximately 5 weeks of data presented.
Yearly graph—1 day average data points with approximately 1 year of data presented.
To quickly create images by using the GD graphics library, go to http://www.boutell.com/gd
About Selecting Dial OIDs
To select which dial OIDs to query when monitoring dial-up activity, see the OIDs listed in the
following tables:
following tables:
Circuit utilization OIDs (Table 14)
Modem information OIDs (Table 15)
User information OIDs (Table 16)
Caution
Be cautious when polling network elements. Polling OIDs that retrieve large amounts of
data can cause CPU problems on a Cisco IOS device. For example, do not get the ARP
table, walk large portions of a MIB tree, poll the wrong OID too frequently, or get statistics
that have an entry for every interface. For example, a Cisco 7200 may have 10 interfaces;
whereas, a Cisco AS5800 may have 3,000 interfaces.
data can cause CPU problems on a Cisco IOS device. For example, do not get the ARP
table, walk large portions of a MIB tree, poll the wrong OID too frequently, or get statistics
that have an entry for every interface. For example, a Cisco 7200 may have 10 interfaces;
whereas, a Cisco AS5800 may have 3,000 interfaces.
In this case study, the tools UCD-SNMP and SNMP Commander were used to inspect and understand
the MIBs. Based on this research, the network engineers at THEnet identified the OIDs in the following
tables to program in to MRTG.
the MIBs. Based on this research, the network engineers at THEnet identified the OIDs in the following
tables to program in to MRTG.
To see the complete structure of the CISCO-POP-MGMT-MIB and CISCO-MODEM-MGMT-MIB,
go to the following URLs:
go to the following URLs:
CISCO-POP-MGMT-MIB
http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/dialnms/popmgt.txt
CISCO-MODEM-MGMT-MIB
http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/dialnms/modemmgt.txt
Table 14
Circuit Utilization OIDs
Variable
Base MIB and OID
Description
Analog calls
CISCO-POP-MGMT-MIB
1.3.6.1.4.1.9.10.19.1.1.2
The number of analog calls connected.
Active DS0s
CISCO-POP-MGMT-MIB
1.3.6.1.4.1.9.10.19.1.1.4
The total number of calls connected.
Call count
CISCO-POP-MGMT-MIB
1.3.6.1.4.1.9.10.19.1.1.1.1.7
The number of calls that have occupied a
specific DS0.
specific DS0.