Service Assurance Agent
From Wikipedia, the free encyclopedia
Service Assurance Agent (SAA) is an active measurement technology that was initially developed by Cisco Systems. SAA is sometimes colloquially referred to as Application Performance Monitor (APM) or its previous name, Response Time Responder (RTR).
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[edit] Functions
Routers and switches enabled with SAA perform periodic network measurements such as
- Hypertext Transfer Protocol (HTTP) GET
- File Transfer Protocol (FTP) downloads
- Domain Name System (DNS) lookups
- User Datagram Protocol (UDP) echo, for VoIP jitter and Mean Opinion Score (MOS)
- Data-Link Switching (DLSw) (SNA Tunneling protocol)
- Dynamic Host Configuration Protocol (DHCP) lease requests
- Transmission Control Protocol (TCP) connect
- Internet Control Message Protocol (ICMP) echo (remote ping)
The exact number and types of available measurements depends on the IOS version. SAA is very widely used in service provider networks to generate time-based performance data. It is also used together with Simple Network Management Protocol (SNMP) and Netflow, which generate volume-based data. SAA is often used to generate data which is need by IP SLAs.
[edit] Usage considerations
- For SAA measurements devices with SAA support are required. SAA is supported on Cisco routers and switches since IOS version 12.1. Other vendors like Juniper Networks or Enterasys Networks support SAA on some of their devices.
- SAA measurements and data collection can be configured either via a console (command-line interface) or via SNMP.
- When using SNMP, both read and write community strings are needed[clarification needed].
- The SAA voice quality feature was added starting with IOS version 12.3(4)T. All versions after this, including 12.4 mainline, contain the MOS and ICPIF[clarification needed] voice quality calculation for the SAA UDP jitter measurement.
[edit] Processing and presentation of data
A software tool is required in order to plot SAA charts, which are available from various vendors, including ProLAN[1], infosim[2], Watch4Net[3], and Hewlett-Packard[4].
[edit] References
- ^ "Web page for the ProLAN NPM Analyst" (in Russian). ProLan. http://www.prolan.ru/solutions/diagnostics/npmanalyst/index.html. Retrieved March 13, 2009.
- ^ "Official website of infosim". infosim. http://www.infosim.net/. Retrieved March 13, 2009.
- ^ "Official website of Watch4Net". Watch4Net Solutions Inc.. http://www.watch4net.com/. Retrieved March 13, 2009.
- ^ "Performance Insight Report Pack for Service Assurance 1.0". Hewlett-Packard Development Company, L.P.. http://www.openview.hp.com/products/ovpi_net/prod_ovpi_net_0002.html. Retrieved March 13, 2009.
