RE Topology Report — Internet2 (AS11537)

How to read this page

This front page is a map of every AS path Internet2 (AS11537) receives from its neighbours — the routes offered to Internet2, including the ones its policy rejected. Use it to find an AS, compare how many prefixes it carries into Internet2, see how those routes measure up on routing security and policy, and open a route graph for one network, a prefix set, a project's nodes, or a class of routes. Each graph has its own guide (the How to understand this graph button in its header); About covers the data behind the report.

The tree

AS is the AS at that position in the path. Rows with a triangle have more downstream ASes; selecting a row opens its route graph.
Accepted is the count of unique prefixes that traverse that AS and passed Internet2 import policy.
Rejected is the count of unique prefixes that traverse that AS but were filtered by policy.
LPP / metric bar summarizes the selected metric over the routes that traverse the AS — every route whose AS path includes it, originated or transited. Routes that reach a downstream network another way do not count toward this AS. For family-split metrics the top bar is v6 and the lower bar is v4; ASPA is a single AS-level bar. The live Bar key under the metric controls explains the active colors. Click a bar to see exact counts for all six metrics.

Metrics

The Metric buttons change the tree's last column. Interesting-first reorders sibling ASes by the selected metric so the riskiest or most unusual cases float upward; Sort family chooses whether v4 or v6 drives that order for family-split metrics.

LPP: Local-preference probe outcome by address family. Green means R&E preferred, amber means AS-path determined, and rose means commodity preferred. Segment width is the share of responsive probed hosts.
More-specifics: How much of the address space routed through this AS is also announced as more-specific routes in the commodity Internet (the RouteViews DFZ) without a matching R&E route. Traffic to those addresses takes the commodity path by longest-prefix match no matter what preference is set. Green is address space R&E still reaches; rose is the diverted share.
ROA: RPKI origin validation of the routes through this AS, by address-space share: valid (a published ROA authorises the announcing origin), no ROA (nothing published, so the origin cannot be verified) or invalid (a ROA covers the prefix but names another origin or a shorter maximum length — Internet2 rejects these).
ASPA: Share of ASes on the routes through this AS (the AS itself and the ASes between it and each origin) with a published RPKI ASPA object versus no ASPA. Each AS counts once.
Prepend: Address-space share whose observed announcement included AS-path prepending. The tree removes prepends before building hierarchy, but this metric keeps the traffic-engineering signal visible.
Default: Whether hosts in these routes appear to hold a full Internet routing table or to follow a default route toward a commodity provider, inferred from how their probe responses return. Green is Full table; neutral is Uses default. Segment width is the share of probe responses.

Accepted, Rejected and every metric are computed over the routes that traverse the AS — the same set its graph draws. LPP, Default and the route graphs' LPP colouring all come from ROOTBEER's Local Preference Probes, which infer a network's R&E vs. commodity preference from where probe responses return; treat them as an indication to check, not a reading of anyone's configuration.

What changed

The strip above the tree compares the day you are viewing with a baseline day: 1 day is the most recent earlier day the report captured, 7 days the day a week back, or pick any captured day. Each chip counts one kind of change — prefixes added or withdrawn; prefixes that lost acceptance (no path accepts them any more) or gained acceptance; prefixes whose rejection status changed while they stayed accepted (a rejected copy appeared or went away); AS-path verdict flips; paths added or withdrawn; origin changes; and RPKI, IRR, ASPA, LPP, commodity more-specific and registration changes. Click a chip for the table behind it. Above a table of paths or status changes, a By first hop line names the Internet2 neighbours the changes arrived through (for prefix tables, By origin AS names their origins) with a count each — one neighbour's session accounting for thousands of rows is the usual story — and clicking one narrows the table to it. AS numbers carry their names where known. Open graph draws the listed prefixes as a custom graph, and for withdrawn items View on <day> opens them on the baseline day. In the tree, ▲ / ▼ badges beside Accepted and Rejected show each AS's movement, and the Changes metric sorts by total churn under Interesting-first. A graph's header has a Changes button for that AS alone. The baseline rides in the URL as since= and an open table as chg=. Change history is built from the daily snapshots, so a freshly deployed report shows it once a first baseline day exists; LPP changes count only with at least five probe responses on both days.

Custom graph

Search jumps to an AS by ASN, name, holder, IP address, or prefix.
Filter builds a graph from a regex over prefixes, prefix holders, or ASNs in paths.
Prefixes builds a graph from one or more CIDR blocks and includes routes contained by those blocks.
Project resources builds a graph around routes tied to a selected project — measurement fleets (NRP, CAIDA Ark, RIPE Atlas, perfSONAR) or community-managed resources (NetSage Science Registry, OSG/OSPool, EGI).
Anycast opens the subset of routes whose prefixes are tagged as anycast.
Show matches lists the matching routes as a table, even when the set is too broad to draw clearly. Open graph draws them as a custom route graph; it is offered while the number of Internet2 neighbours the routes arrive through is within Max peers, since a graph fed by more entrances than that becomes unreadable — raise the limit or narrow the query.

Route class tabs draw ready-made graphs: Project resources, Anycast, Bogons (unregistered ASNs or prefixes), Private ASNs (leaked RFC 6996 private-use ASNs), Tier-1 (routes transiting a settlement-free-clique Tier-1 carrier, which Internet2 rejects) and Unexpected R&E paths (prefixes outside the R&E topology whose LPP probe responses mostly returned over the R&E path — a possible sign of R&E routes reaching networks they shouldn't; pick an origin to graph the R&E ASes whose routes intersect it). Custom graphs behave like AS graphs, with the extra Split: Internet2 in the middle layout.

Header links and View day

Report status shows when each upstream data source was last refreshed and how many items it holds; Data Sources describes every source the report draws on.
View day replays the report as it stood on a past day — the route snapshot and its annotations frozen as captured, with the chosen day kept in the URL (date=). Return to live (or clearing the date) brings back the current data.
Participate opens the project's participation guide (a shared document) for networks and operators who want to take part.

Links to the guides

Every view on this page is a shareable URL, and so are the guides: #help=page opens this one, #help=about the About page, and help=graph added to any graph URL (for example #asn=11164&help=graph) opens that graph with its guide on top.

About the RE Topology Report

The RE Topology Report visualizes the Research & Education routing topology that converges on Internet2's AS11537. It's built from a snapshot of every BGP route received by Internet2 from its eBGP neighbors — pre-policy, so you see what neighbors announce, not just what Internet2 chose to install. Both accepted routes (those that passed Internet2's import policy and ROV) and rejected routes (those that violated policy and were filtered) are kept and labelled, so you can see the full set of paths neighbors offer to Internet2 and where filtering happens.

The data

BGP routes — a snapshot of every pre-policy route received by Internet2 (AS11537) on each of its eBGP sessions. Each route carries a prefix, an AS-path, and a flag indicating whether Internet2's import policy accepted or rejected it. Consecutive duplicate ASes in the AS-path (path-prepending) are collapsed before aggregation.
AS organization names — CAIDA's as-org2info dataset, refreshed every 24h. Provides the friendly operator name shown next to each AS number (e.g. AS3356 — Level 3 Parent, LLC).
RIPE Stat fallback — for ASes that CAIDA's join doesn't cover (LACNIC and AFRINIC coverage in the CAIDA dataset is historically spotty), the report queries RIPE Stat's as-overview and whois endpoints and uses the resulting holder string. RIPE Stat aggregates whois from every RIR.
Prefix holder names — RIPE Stat whois with an ARIN RDAP fallback chain (rdap-bottom → /registry/ip/), used to populate the holder column in the per-AS prefix lists. Lookups are cached at 24h ± 4h so repeat builds don't re-hit the upstream services.
Route annotations — the per-prefix and per-AS signals shown throughout: RPKI ROAs (origin validation), published ASPA objects, IRR route objects (RADB and the registries it mirrors), ROOTBEER's Local Preference Probe results (R&E vs. commodity preference and default-route behaviour, inferred from probe return paths), a daily RouteViews snapshot of how the commodity Internet reaches the same networks (more-specifics, the Commodity routes overlay, and address space announced only to commodity), RIR delegated statistics (registered vs. unregistered space), the UT-DACS / manycast.net anycast census, and the public inventories of NRP, CAIDA Ark, RIPE Atlas, perfSONAR, OSG, EGI and NetSage Science Registry nodes. Report status in the header shows when each was last refreshed; Data Sources describes each one.

The tree (front page)

The front page is a hierarchical tree of every AS that appears in any AS-path Internet2 received. The root is AS11537; its direct children are Internet2's eBGP neighbors; their children are the next AS in those neighbors' paths; and so on down to the origin AS that announced each prefix.

Click the ▶ toggle on a row to expand its sub-tree; click again to collapse.
Select the AS pill (the AS… — name chip) to open the focused Sankey view for that AS.
The two numeric columns (right-aligned, alternating background) show, for the AS at that tree position:
- Accepted — count of distinct prefixes whose path traverses this AS and that Internet2 accepted into its forwarding table.
- Rejected — count of distinct prefixes whose path traverses this AS but that Internet2's import policy rejected: RPKI invalid, a tier-1 carrier or a private-use ASN in the path, a prefix longer than /27 (IPv4) or /49 (IPv6), or a per-customer prefix filter.
Tooltip on each numeric cell adds the originated count when the AS is itself the origin (e.g. “1,243 accepted prefixes through AS3356 (12 originated here)”).

The route graph

Selecting an AS opens a full-window Sankey graph of every distinct AS path by which that AS's routes reach AS11537: origin ASes on the left, Internet2 on the right, one ribbon per AS path with its thickness set by the number of prefixes it carries, and AS11537's bar split into the routes Internet2 accepted and those it rejected. Colour names the Internet2 neighbour that delivered each route; red is always a rejected route. From the graph you can trace and list routes, filter by address family, hop count, regex or hidden ASes, colour ribbons by LPP result or commodity more-specifics, overlay the commodity Internet's paths to the same networks, table every prefix with its routing-security and policy annotations, and build a written AS Report on what is visible. The How to understand this graph button in the graph's header opens the full guide to all of it; the ← All ASes arrow (or Esc) returns to the tree.

Search

The search box accepts an AS number (AS27343 or just 27343), a partial AS or holder name, an IP address, or a prefix (192.0.2.0/24). IPs and prefixes are matched with longest-prefix match against every announced prefix in the report, so you can drop in any IPv4 or IPv6 address and jump to the AS that originates its covering prefix. Activating a result opens the route graph for that AS.

Sharing

Every view is a URL: the tree's metric and sort settings, the day being viewed, and a graph's complete state all live in the page hash, so copying the address bar reproduces what you see. The guides are linkable too — #help=about opens this page, #help=page the front-page guide, and help=graph on a graph URL its guide.

Attribution

This tool is part of the ROOTBEER (Routing Operations Observational Technology: Building to Enable Education and Research) suite, a joint effort between Internet2 and CAIDA (the Center for Applied Internet Data Analysis at UC San Diego). Internet2 contributes the BGP route snapshots and operational policy context; CAIDA contributes the AS-organization, AS-relationship, and topology datasets that power the rest of the suite.

This material is based on research sponsored by the National Science Foundation (NSF) grant OAC-2530871. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of NSF.

Report status — freshness

Each row below shows when this report's view of that upstream feed was last refreshed. The BGP-route fetch runs once at process startup; per-session entries older than 72 hours are evicted from the on-disk cache.

Source	Last refreshed	Items	Notes