Inter-Chassis Session Recovery Architecture; Session Recovery Improvements; Impact On Xdr File Naming - Cisco ASR 5000 Series Administration Manual

Enhanced Charging Service Overview
Upon completion of the switchover, the ECS sessions are maintained and the "now-active" chassis recreates all of the
session state information including the generation of new xDRs.
In the event of an unplanned switchover, all accounting data that has not been written to the external storage is lost.
(Note that either the ESS can pull the xDR data from the chassis, or the chassis can push the xDR files to a configured
ESS at user-configured intervals. For more information, see
switchover, the ECS sessions are maintained and the "now-active" chassis recreates all of the session state information
including the generation of new xDRs.
Regardless of the type of switchover that occurred, the names of the new xDR files will be different from those stored in
the /records directory of packet processing card RAM on the "now-standby" chassis. Also, in addition to the file name,
the content of many of the fields within the xDR files created by the "now-active" chassis will be different. ECS
manages this impact with recovery mechanism. For more information on the differences and how to correlate the two
files and other recovery information, see the

Inter-chassis Session Recovery Architecture

Inter-chassis redundancy in ECS uses Flow Detail Records (FDRs) and UDRs to manage the switchover between
Active-Standby system. xDRs are moved between redundant external storage server and Active-Standby systems.

Session Recovery Improvements

In StarOS releases prior to 14.0, there were only 10 PCC rules that were recovered per bearer in the event of a session
manager crash. In 14.0 and later releases, this limit has been increased to 24. That is, up to 24 PCC rules can be
recovered post ICSR.
With the increase in the limit of PCC rules that can be recovered, the rules are not lost and hence the charging applied to
the end users are not impacted.

Impact on xDR File Naming

The xDR file name is limited to 256 characters with the following syntax:
basename_ChargSvcName_ timestamp_SeqNumResetIndicator_FileSeqNumber
where:
 basename—A global configurable text string that is unique per system that uniquely identifies the global
location of the system running ECS.
 ChargSvcName—A system context-based configurable text string that uniquely identifies a specific context-
based charging service.
 timestamp—Date and time at the instance of file creation. Date and time in the form of
"MMDDYYYYHHmmSS" where HH is a 24-hour value from 00-23.
 SeqNumResetIndicator—A one-byte counter used to discern the potential for duplicated FileSeqNumber with a
range of 0 through 255, which is incremented by a value of 1 for the following conditions:
 Failure of an ECS software process on an individual packet processing card
 Failure of a system such that a second system takes over according to the Inter-chassis Session
 File Sequence Number (FileSeqNumber) rollover from 999999999 to 0
Recovery feature
External Storage System
Impact on xDR File Naming
Cisco ASR 5x00 Enhanced Charging Services Administration Guide ▄
Redundancy Support in ECS ▀
section.) Upon completion of
section.
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