Cisco Cisco ASR 5000 Guida Alla Risoluzione Dei Problemi
STP Congestion, IMSIMGR Over State, and SCTP
Link Flaps in SGSN Due to HLR MAP_RESET
Link Flaps in SGSN Due to HLR MAP_RESET
Document ID: 118937
Contributed by Krishna Kishore D V, Cisco TAC Engineer.
Apr 16, 2015
Contents
Introduction
Background Information
Problem
Solution
STP Link Receives Too Much Traffic
IMSIMGR in Warn State
HLR Failure
Recommendations
Traffic Flow
Triggers for M3UA Congested Alarm in SGSN
Background Information
Problem
Solution
STP Link Receives Too Much Traffic
IMSIMGR in Warn State
HLR Failure
Recommendations
Traffic Flow
Triggers for M3UA Congested Alarm in SGSN
Introduction
This document describes a problem that is encountered on the Serving General Packet Radio Service (GPRS)
Supporting Node (SGSN) of the Cisco 5000 Series Aggregated Services Router (ASR). Some possible
workarounds for this issue are also described.
Supporting Node (SGSN) of the Cisco 5000 Series Aggregated Services Router (ASR). Some possible
workarounds for this issue are also described.
Background Information
This specific chain of events on the ASR SGSN is described in this document:
Nov 21st, 6:25 AM: A MAP_RESET was sent by the Home Location Register (HLR).
1.
Nov 21st, 8:13 AM: A congestion alarm is raised for Signal Transfer Point 2 (STP−2).
2.
Nov 21st, 8:23 AM: A congestion alarm is raised for STP−1 and STP−2.
3.
Nov 21st, 8:48 AM: The International Mobile Subscriber Identity Manager (IMSIMGR) moves into
the warn state.
the warn state.
4.
Nov 21st, 10:07 AM: The links reset from STP−2 towards the SGSN.
5.
Nov 21st, 10:15 AM: Improvement is observed in the SGSN Location Update (LU) stats.
6.
Nov 21st, 10:00 10:30 AM: The statistics begin to improve at 10:00 am.
7.
Nov 21st, 11:15 AM : A decline is observed in the SGSN LU stats.
8.