Introduction

With the fast growth of high performance networks, users pay more attention to network traffic conditions, especially when they are running a high-performance distributed application over wide-area network. A network performance report may help users figure out the quality of the network service and the available bandwidth, as well as identifying the traffic pattern on the network in order to avoid heavy traffic.

There are two basic questions to be answered:

1. What is the condition between site A and site B?
2. What is the overall traffic status of the vBNS/Abilene backbone?

The first question is addressed in two current site-to-site measurement projects, NLANR's AMP and Advanced Network & Services' Surveyor. In these two projects, a set of measurement machines is deployed at participating organizations, and users can see the current and past network conditions between campuses via a web browser.

The second question is addressed by the backbone measurements published on the web by each of the vBNS and Abilene network operation centers. Those data are collected from the backbone devices and directly attached hosts. It provides the overview of the backbone status and conditions.

AMP and Surveyor will be covered in the next section, followed by a section about vBNS and Abilene backbone measurements. The last section will discuss some issues related to the actual performance as seen by the application users.

The AMP and Surveyor projects are deployed at participating organizations to do site-to-site measurements.

• AMP
• Surveyor

AMP/Surveyor and the backbone measurements are targeted for different audiences. AMP/Surveyor provides user-oriented site-to-site measurements, while the vBNS/Abilene backbone measurement described below gives network engineers backbone status information. The backbone measurements are important for diagnosing wide-area network problems, but can be difficult to understand unless you have adequate lower-layer networking knowledge and some idea of the wide-area backbone topology.

• Abilene
• vBNS

AMP and Surveyor give users site-to-site performance results between the measurement machines, but not the users' actual desktops. The relevance of the AMP/Surveyor results depends on where the measurement machines are installed.

AMP and Surveyor have different philosophies towards placing the measurement machines. AMP tries to place the machine so it can serve as a "representative machine" for the local campus, and thus the measurements should be compatible with the results to a user's desktop system. In Surveyor, the placement of the machine should be on a LAN segment as close to the wide-area network as possible, because Surveyor is intended to measure the wide-area network characteristics between campuses. As a result, the local-area network performance when viewed with Surveyor is hidden.

To get the actual result, users may need to measure the network performance between workstations. For more information about how to test round-trip-time, routing, and maximum TCP throughput at user's desktop, refer to the article Are you using the fast lane of Internet?.

1. Participants Guide to the Surveyor Daily Summary Reports, Sunil Kalidindi, Advanced Network & Services, November 1998.
2. Active Measurement of the vBNS, NLANR Measurement & Operations Analysis Team.
3. AMP Homepage
4. Surveyor Homepage
5. vBNS Network Traffic and Performance Monitoring Homepage
6. Abilene Network Operation Center Homepage
7. Are you using the fast lane of Internet?, NLANR Distributed Application Support Team, Alliance data link Newsletter, April 1999.