Cisco Cisco ASR 5700 Manual Técnica
Contents
Introduction
Background Information
GGSN Behavior
Cause Code 192 Error
Example Scenarios
Introduction
This document describes the behavior of the Gateway General Packet Radio Service (GPRS)
Supporting Node (GGSN) when the Serving GPRS Supporting Node (SGSN) does not respond to
the GPRS Tunneling Protocol (GTP) echo request that is sent from the GGSN.
Supporting Node (GGSN) when the Serving GPRS Supporting Node (SGSN) does not respond to
the GPRS Tunneling Protocol (GTP) echo request that is sent from the GGSN.
Background Information
You might experience high Packet Data Protocol (PDP) activation failures in the GGSN during a
period of time when the SGSN does not respond to the GTP echo requests. Here are some
questions that might arise in this scenario:
period of time when the SGSN does not respond to the GTP echo requests. Here are some
questions that might arise in this scenario:
Do the Create PDP or Update PDP requests from the SGSN arrive at the GGSN?
1.
When the GTP echo requests fail from the GGSN to the SGSNs, how should the GGSN
behave if the Update PDP context that is sent from the GGSN does not receive a response?
behave if the Update PDP context that is sent from the GGSN does not receive a response?
2.
How does a GGSN fail a PDP if it does not receive a GTP echo response or a response for
the non-echo request messages that arrive from an SGSN for that PDP?
the non-echo request messages that arrive from an SGSN for that PDP?
3.
How does a lack in GTP echo/non-echo responses directly affect the PDP activation
failures?
failures?
4.
GGSN Behavior
If the messages do not arrive at the GGSN, then the SGSN triggers a path failure alarm and
silently drops them. Additionally, if there is no echo response received for the echo request that is
initiated by the GGSN, it indicates that the peer is down, so the GGSN locally clears the calls that
are related to that peer.
silently drops them. Additionally, if there is no echo response received for the echo request that is
initiated by the GGSN, it indicates that the peer is down, so the GGSN locally clears the calls that
are related to that peer.
In the show support details command output, or the show gtpc statistics verbose command
output, you can view the GGSN Req Timeout counters:
output, you can view the GGSN Req Timeout counters:
#show gtpc statistics verbose
SGSN Restart: Timeout:
Create PDP Req: 5 GTPC Echo Timeout: 149160
Update PDP Req: 0 GTPU Echo Timeout: 0
Echo Response: 312 GGSN Req Timeout: 24182