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R&E Global LPP Report

The attached HTML file is a self-contained, interactive copy of the report. Open it in any modern web browser to explore the full tree with search, sort, and expand/collapse controls.

What this report shows

The global R&E network consists of roughly 2,700 separate networks (autonomous systems). A significant percentage of these networks have connections to both an upstream R&E provider and one or more commodity ISPs. Each network independently decides which path to prefer when routing traffic to various destinations.

Campuses typically connect to a regional R&E network (e.g., MERIT, LEARN, CENIC, NYSERNet), which in turn connects to Internet2. The R&E route between two campuses is often at least 4 AS hops. If both campuses use the same commodity ISP — which happens frequently — the commodity route might only be 2 hops. Without an explicit routing policy, BGP selects the shortest AS path, and the two campuses will route via the commodity ISP instead of the R&E network.

The recommended best practice is to use BGP Local Preference to prefer routes learned from R&E networks over routes learned from commodity ISPs. When this is done, campuses route via the R&E path regardless of AS-path length.

This report visualizes routing preference data for all 2,700 R&E networks, organized as an AS-path tree rooted at Internet2 (AS 11537).

How the probe works

The Local Preference Probe (LPP) is a server connected to both the Internet2 R&E network and a commodity ISP. It sends probes from two source addresses to hosts across the R&E networks and observes how each network routes its response back — does it arrive via the R&E path or the commodity path?

Source	Address	Route design
Source A	163.253.64.1	R&E route is prepended towards commodity
Source B	163.253.63.63	R&E route is prepended towards R&E

Both sources share the same commodity route. The difference is which direction the R&E route is prepended, so the two probes test whether the remote network chooses based on Local Preference or AS-path length.

Reading the results

Each network in the tree has a stacked bar showing three categories:

Color	Source A return	Source B return	Meaning
Green (RE)	R&E	R&E	The network follows the best practice of preferring R&E routes over commodity. BGP Local Preference favors R&E.
Orange (Path)	R&E	Commodity	The network uses AS-path length to choose, so some destinations use R&E while others route via commodity. R&E and commodity have equal Local Preference.
Red (Comm)	Commodity	Commodity	The network appears to always prefer commodity, even when an R&E route exists.

Probes that are inconclusive (missing or unexpected return pattern) are excluded from the percentages.

Orange and red networks are connected to the global R&E network infrastructure, but are not effectively using it.

Customer cone percentages

The stacked bar for each AS represents its customer cone — the AS itself plus every AS downstream of it in the R&E tree:

• Each probed destination IP is classified as RE, Comm, or Path.
• Counts are summed across the entire cone: the AS's own prefixes plus all downstream prefixes.
• The three bar segments show each category's share of the cone total, summing to 100%.

A leaf AS shows only its own results. A transit AS near the root aggregates results across hundreds of downstream networks.

Navigating the report

• Expand/Collapse: Click any AS row to expand or collapse its children. Use the "Expand all" and "Collapse all" buttons for bulk control.
• Search: Type an AS number or name in the search box to highlight matches and auto-expand their location in the tree.
• Sort: Click the RE, Comm, Path, or Pfx column headers to sort children within each expanded subtree. Click again to reverse direction, a third time to reset.
• Prefixes: Click the "N pfx" link on any AS to see its originated prefixes. Each prefix links to the per-prefix probe tool.
• Duplicates: An AS that appears under multiple parents is fully rendered only once. Subsequent appearances show a "see above" link that scrolls to the first occurrence.
• AS names: Toggle between names and holder names using the "Show AS holder" button.

Data sources

Source	Used for
RouteViews	BGP AS paths and prefix origin data for R&E prefixes
RIPE Stat	AS names and holder information
CAIDA AS Organizations	Fallback AS name data
lpp-store	Historical LPP probe results used to compute cone percentages

In the future, the report will be rebuilt daily at UTC midnight.

Project

This report is part of the CICI-ROOTBEER project.

Steven Wallace
Director - Routing Integrity
Internet2
ssw@internet2.edu