BGP and Internet Routing Lecture Notes

This set of vocabulary flashcards covers the fundamental concepts of Border Gateway Protocol (BGP), network routing, security vulnerabilities like hijacking and leaks, and defense mechanisms like RPKI.

BGP (Border Gateway Protocol)

The protocol that figures out how to get from point A to point B with a given IP address across the map of the Internet.

Autonomous Systems (AS)

Very large networks linked together that share information about how to get from a to b; the Internet is described as a "network of networks" composed of these systems.

BGP router

A router within an autonomous system that listens for advertisements of new routes from other routers and shares known routes using the BGP protocol.

Advertisements

Messages exchanged between routers where an autonomous system identifies an IP prefix it can reach and the specific path used to reach it.

IP Prefix

A slice or chunk of the total IP range subdivided among IP holders like ISPs.

Local Policy

Criteria used by a BGP router to judge the best route, often based on business relationships with other autonomous systems.

Tier 1 ISP

Top-level autonomous systems that do not pay anyone for connectivity, but instead receive payment from all other networks to provide reachability.

Black holing

A situation resulting from bad route advertisements where traffic is directed to a place where it goes nowhere, disrupting traffic.

Prefix Hijacking

A malicious event where an autonomous system that is not authorized to originate a prefix claims to be the origin for that prefix.

Route Leak

A violation of business relationship principles, often not malicious, where an autonomous system shares routes with parties they should not, potentially causing availability issues.

Path Manipulation

A malicious act where an entity shortens a path in an advertisement to make it look more attractive so routers prefer their route.

Longest Matching Prefix

A routing rule where the most specific prefix (the one with the higher number after the slash, such as $/25$ over $/24$) is selected if an IP matches multiple rules.

IANA (Internet Assigned Numbers Authority)

The body at the very top of the hierarchy that distributes large chunks of IP addresses to regional registries.

RIR (Regional Internet Registry)

Regional bodies, such as APNIC in the Asia Pacific, that distribute or delegate IP prefixes to holders like the University of Auckland.

RPKI (Resource Public Key Infrastructure)

A defense mechanism against prefix hijacking that uses certificates to validate if an autonomous system is authorized to originate a prefix.

ROA (Route Origin Authorization)

A signed statement binding an IP prefix and an AS number to demonstrate authorization to originate that prefix.

Resource Certificates

A subtype of $X.509$ certificates that bind IP prefixes and AS numbers to a public key, with the RIR acting as the trust anchor.

RPKI Validator

A tool that checks ROA signatures and chains of trust back to the regional Internet registry to provide a validated payload set to BGP routers.

Host Name Verification

A security check where a browser ensures the certificate for a site like myetherwallet.com matches the requested domain, serving as a defense when BGP routing is compromised.