CONCEPT Cited by 2 sources
Traffic engineering¶
Traffic engineering in the context of inter-domain routing refers to the deliberate manipulation of BGP attributes by an Autonomous System to influence how traffic enters and exits its network. The goal is typically one or more of: attracting more traffic (revenue for transit providers), preferring cheaper links, balancing load across multiple paths, or deprioritizing less-desirable routes.
Techniques¶
| Technique | Attribute manipulated | Direction | Visibility |
|---|---|---|---|
| AS_PATH prepending | AS_PATH length (step 2) | Outbound — make own routes less preferred to peers | Visible in public routing tables |
| ORIGIN rewriting | ORIGIN (step 3) | Inbound — make received routes more preferred vs competitors | Not supposed to happen per RFC 4271 |
| MED signaling | MED (step 4) | Outbound — hint to neighbor which entry point to prefer | Often filtered by receiving AS |
| Local Preference tuning | Local Preference (step 1) | Internal — strongest lever but only within the AS | Not visible externally |
| Community-based | Various | Signal to upstream to apply specific policies | Requires cooperation |
ORIGIN manipulation as traffic engineering¶
Cloudflare's 2026 controlled experiment found that ORIGIN attribute rewriting is a widespread, undisclosed traffic-engineering technique concentrated among Tier-1 transit providers. By setting ORIGIN=IGP on routes they carry (regardless of the actual origination method), these providers make their routes win the step-3 tiebreaker against competitors who comply with RFC 4271's SHOULD NOT guidance — attracting traffic and revenue. ~70% of observed AS_PATHs showed this manipulation; 6 out of 16 Tier-1 ASes participate. (Source: sources/2026-07-24-cloudflare-bgp-origin-attribute-manipulation)
Revenue dynamics¶
Traffic engineering at the inter-domain level is inherently a competitive, revenue-driven activity. Unlike intra-domain TE (which optimizes internal link utilization), inter-domain TE shapes the commercial relationship between transit providers and their customers. The ORIGIN manipulation arms race — once one Tier-1 rewrites, competitors must follow — is a canonical example of how routing-policy decisions are ultimately business decisions.
Seen in¶
- sources/2026-07-24-cloudflare-bgp-origin-attribute-manipulation — ORIGIN rewriting as the primary revenue-driven TE technique
- sources/2026-01-08-cloudflare-a-closer-look-at-a-bgp-anomaly-in-venezuela — AS_PATH prepending as a TE signal (9× prepending by AS8048 as evidence against intentional traffic attraction)