Cisco Cisco ASR 5000 Manuel Technique
Introduction
This document describes how to configure the congestion control mechanism on the Cisco Aggregated
Services Router (ASR) 5x00 Series. The congestion control functionality that is described in this document is
primarily applied to the Serving General Packet Radio Service (GPRS) Support Node (SGSN) and Mobility
Management Entity (MME) network functions.
Services Router (ASR) 5x00 Series. The congestion control functionality that is described in this document is
primarily applied to the Serving General Packet Radio Service (GPRS) Support Node (SGSN) and Mobility
Management Entity (MME) network functions.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
This document is not restricted to specific software and hardware versions.
The information in this document was created from the devices in a specific lab environment. All of the
devices used in this document started with a cleared (default) configuration. If your network is live, make sure
that you understand the potential impact of any command.
devices used in this document started with a cleared (default) configuration. If your network is live, make sure
that you understand the potential impact of any command.
Congestion Control Overview
At times, an excessive load can be observed in the network, which can result in a license breach, high CPU
utilization, high port utilization, or high memory utilization. This can cause performance degradation on the
node that is under heavy load, but these conditions are usually temporary and are quickly resolved.
Congestion control is used in order to aid in the identification of such conditions and invoke the policies that
address the situation when these heavy load conditions persist continuously, or a large number of these
conditions exist.
utilization, high port utilization, or high memory utilization. This can cause performance degradation on the
node that is under heavy load, but these conditions are usually temporary and are quickly resolved.
Congestion control is used in order to aid in the identification of such conditions and invoke the policies that
address the situation when these heavy load conditions persist continuously, or a large number of these
conditions exist.
This section describes the congestion control mechanism in the SGSN and the MME, as per the 3rd
Generation Partnership Project (3GPP).
Generation Partnership Project (3GPP).
MME/SGSN Congestion Control
The MME provides a Non−Access Startum (NAS) level congestion control mechanism, which is based on
Access Point Name (APN) or General NAS−level Mobility Management (MM) control.
Access Point Name (APN) or General NAS−level Mobility Management (MM) control.
The APN−based congestion control mechanisms can handle the Evolved Packet System (EPS) Session
Management (ESM) and EPS Mobility Management (EMM) signalling that is associated with the User
Equipment (UE) that has a particular APN and UE. The network should support this congestion control
function. The MME detects the NAS−level congestion control that is associated with the APN, and it starts
and stops the APN−based congestion control in accordance with this criteria:
Management (ESM) and EPS Mobility Management (EMM) signalling that is associated with the User
Equipment (UE) that has a particular APN and UE. The network should support this congestion control
function. The MME detects the NAS−level congestion control that is associated with the APN, and it starts
and stops the APN−based congestion control in accordance with this criteria:
Maximum number of active EPS bearers per APN
•
Maximum number of EPS bearer activations per APN
•
One or more Packet Data Network (PDN) Gateways (PGWs) on an APN is not reachable or indicates
congestion to the MME
congestion to the MME
•