Nas Signalling Security - Cisco ASR 5000 series Product Overview

Mobility Management Entity Overview
resolved. However, continuous or large numbers of these error conditions within a specific time interval may be
indicative of larger, more severe issues. The purpose of thresholding is to help identify potentially severe conditions so
that immediate action can be taken to minimize and/or avoid system downtime.
The system supports Threshold Crossing Alerts for certain key resources such as CPU, memory, number of sessions etc.
With this capability, the operator can configure threshold on these resources whereby, should the resource depletion
cross the configured threshold, a SNMP Trap would be sent.
The following thresholding models are supported by the system:
Alert: A value is monitored and an alert condition occurs when the value reaches or exceeds the configured high
threshold within the specified polling interval. The alert is generated then generated and/or sent at the end of
the polling interval.
Alarm: Both high and low threshold are defined for a value. An alarm condition occurs when the value reaches
or exceeds the configured high threshold within the specified polling interval. The alert is generated then
generated and/or sent at the end of the polling interval.
Thresholding reports conditions using one of the following mechanisms:
SNMP traps: SNMP traps have been created that indicate the condition (high threshold crossing and/or clear) of
each of the monitored values.
Generation of specific traps can be enabled or disabled on the chassis. Ensuring that only important faults get displayed.
SNMP traps are supported in both Alert and Alarm modes.
Logs: The system provides a facility called threshold for which active and event logs can be generated. As with
other system facilities, logs are generated Log messages pertaining to the condition of a monitored value are
generated with a severity level of WARNING.
Logs are supported in both the Alert and the Alarm models.
Alarm System: High threshold alarms generated within the specified polling interval are considered
―outstanding‖ until a the condition no longer exists or a condition clear alarm is generated. ―Outstanding‖
alarms are reported to the system's alarm subsystem and are viewable through the Alarm Management menu in
the Web Element Manager.
The Alarm System is used only in conjunction with the Alarm model.
Important:
Guide.

NAS Signalling Security

It provides integrity protection and encryption of NAS signalling. The NAS security association is between the UE and
the MME.
The MME uses the NAS security mode command procedure to establish a NAS security association between the UE
and MME, in order to protect the further NAS signalling messages.
OL-22938-02
For more information on threshold crossing alert configuration, refer Thresholding Configuration
Features and Functionality - Base Software ▀
Cisco ASR 5000 Series Product Overview ▄