Keynote's Internet Health Report is a service that measures the latencies between all of the major Tier 1 backbone providers in the United States. That service has been expanded in the AT&T Internet Health Report to include AT&T's private MegaPOP locations.

Keynote measurement agents monitor latency, availability, and packet loss. The data is summarized to show:

• Performance within the AT&T network.
• Performance of the Internet peering points between the AT&T network and each major provider.
• Performance of the other Internet providers and the peering points among them.

Keynote Business 40 Index

Keynote maintains a performance index known as the Keynote Business 40 (KB40), which is computed by measuring and then averaging the performance of 40 leading Web sites spread across different business sectors. This index is useful as an indicator of "typical" Internet performance for the business user. To allow for a comparison of typical business user performance from the AT&T network, the standard KB40 Index has been extended to include performance and availability measurements of the same 40 Web sites taken from selected MegaPOP locations. Each site in the index is measured at the same frequency (every 15 minutes) as the public KB40 index.

Network Locations

The AT&T Internet Health Report summarizes the performance of the AT&T network from many vantage points, for several time periods. Data in the report is presented by network location and time period, using the following groupings:

ISP
Measurements taken from multiple locations are grouped and presented for each tier-1 backbone provider.

Network Engineering

MegaPOP
These are physical AT&T IP POPs that serve as key traffic aggregation points on the AT&T IP backbone network in those states where Long Distance regulatory relief is obtained. MegaPOPs connect to other ISPs' and Content Providers' networks, interconnect to other AT&T MegaPOPs via AT&T's IP Backbone, and interconnect to AT&T MiniPOPs. MegaPOPs also serve as data centers which support applications such as E-Mail, UseNet News, content servers and other applications. AT&T's local Dial-up, High Speed Internet (HSI), and Dedicated Internet Access customer circuits are connected to these POPs as well.

MiniPOP
These are physical IP POPs that primarily serve to locally connect to AT&T's Dial-up, HSI, and Dedicated Internet Access customers. Once Long Distance relief is obtained by AT&T in a particular state, AT&T MiniPOPs are dual-homed to two, diverse AT&T MegaPOPs via multiple interLATA transport carriers. Customer IP traffic is routed across the AT&T IP Backbone to its final destination.