Bean-Counting IP
The trouble with homegrown methods of measuring IP network performance is that so many results can be irrelevant or misleading. Benchmarking how fast you can fetch a Web page doesn't necessarily take into account variables like the speed of the Web server and its connection, or whether TCP itself is properly tuned.
And taking "snapshots" of network performance with network management tools based on SNMP, which entails tallying information like the number of packets dropped, doesn't address round-trip delays or jitter on the line, according to Fred Baker, chairman of the IETF.
It's this inability to take an accurate pulse of IP-based services that has hampered Internet service providers' efforts to get class-of-service or differentiated IP services off the ground.
Measuring Loss
But soon there will be
a standard way to measure packet loss and delay, and eventually to calculate how much data you can move over a congested network.
The IETF's IPPM (IP Performance Metrics) working group is about to firm up these metrics, whose specifications most likely will be available through the public-domain code on the Internet; most of the tools and resources for various methods of measurement are available for free.
This standard method of measuring the performance of an IP network may also find its way into some of today's commercial network measurement tools. ISPs and their customers hope to get an accurate reading of just how an IP service or network is performing, which in turn, will give ISP customers some ammunition when they eventually subscribe to a higher-grade IP service, for instance. Standardized metrics would let ISPs spot and fix any network performance problems, according to Vern Paxson, co-chairman of the IETF IPPM working group.
Keeping Track of Business
ISPs are keenly aware that th
ey need to get a better hand on Internet performance given the cutthroat competition in that arena to attract and keep customers. According to some estimates, ISP customers turn over at a 40 percent clip. Many users say they simply become disillusioned with the quality of their IP services.
The IETF and other members of the traditional research community, including the XIWT (Cross Industry Working Team) and several key ISPs like ANS, are pushing for solid ways to measure IP performance. The goal is to open the door for different grades of IP service, such as a pricier one for video.
MCI, which by year's end will use a homegrown network-troubleshooting tool as part of its services for IP and other data services, plans to implement the IETF's IPPM specs in its software, according to Jim Parkhurst, MCI's senior staff engineer for product and technical support.
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