Practical Implementation of BGP Community with Geotags
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The document discusses the practical implementation of BGP (Border Gateway Protocol) communities with geotags to enrich routing information. It explains the use of geocoding and BGP communities as a means to tag routes with geographical data, enhancing traffic engineering and network management. Additionally, it outlines types of community tags and their use in providing actionable routing information for both service providers and customers.
Practical Implementation of BGP Community with Geotags
- 1. Practical Implementation of BGP Community with Geotags Muhammad Moinur Rahman 1Asia Alliance Communication Ltd moin@1asia-ahl.com
- 2. GeoTAGS • Geographical Identification Metadata • A form of GeoSpatial Metadata – Applicable to objects that have GeoGraphic Extent – Or applicable to objects with some position on this Earth – Objects like Photo, Audio/Video Files, SMS Messages – Unlikely but true DNS information (LOC resources) • Facebook Check-in or Photos @ – Adds Geotaggs in our Facebook updates – Adds Geotaggs in our Facebook Photos
- 3. Geotags in BGP Routes • A router is a device which intelligently routes packets – Not a Phone – Not a Camera – Not a GPS Device • How can we add metatags in a route? – GeoCoding
- 4. Geocoding • A process of enriching description of a location • Most frequently a postal address/place with GeoGraphic co-ordinates – From a Spatial Reference Data • Or reverse Geocoding • Enriching a GeoGraphic Co-ordinate with a postal address/place – Facebook/Google Plus and other social sites use reverse Geocoding for our Check-in
- 5. BGP routes with location information • Routers don’t have a builtin GPS device • Need a process to manually Geocode it’s route-origin • Need to add a tag to the route objects or group of routes • Answer : BGP Communities
- 6. BGP Communities • A BGP attribute (RFC1997) • A mechanism for coloring or (GEO)tagging route destinations or a group of route destinations • A 4-byte value (RFC1998) • Two types of communities – Regular – Extended
- 7. BGP Communities(Contd) • A 32-bit integer isn’t always easy to work with – More common convention is to split into two 16-bit values – Commonly <local-ASN>:value e.g 10102:0 (Sorry no help for 4 byte ASNs) – Specially reserved (0:0 – 0:65535 and 65535:0 – 65535:65535) – First value is intended to define the scope or “target” • So you know if this community is “for you” or someone else • So two networks don’t do conflicting things with the same data – Second value is arbitrary data for the targeted network • Whatever data you’re trying to encode
- 8. BGP Community Tags • Can be added to a particular prefix – set community 10102:100 – Set community 10102:90 additive • Can be matched by route-map – ip community-list PEER-ROUTES 10102:6600 – community-set PEER 10102:31021 end-set • Can be deleted from particular prefixes • Full control over community tags
- 9. Cause • A scalable network needs them for its own use – Be able to identify customers, transits, peers, etc – To perform traffic engineering and export controls – There is no other truly acceptable implementation • But customers love using them as well – “Power user” customers demand this level of control. – Having self-supporting customers doesn’t hurt either. – The more powerful you make your communities, the more work it will save you in the long run.
- 10. Practical consideration • Most routers parse BGP communities as strings rather than integers, using Regular Expressions. – Design your community system with this in mind. – Think strings and character positions, not numbers. – For Example, 10102:1234 can easily be parsed as • Field #1, Value 1 • Field #2, Value 23 • Field #3, Value 4 – But can’t easily be parsed numerically • For example as “larger than 1233”. – Remember not to exceed 65535 as a 16-bit value. (65536 options) to represent • Carried across AS
- 11. Types of Implementation • Practical BGP Communities Implementation can essentially be classified into two types: • Informational tags – Communities set by and sent from a provider network, to tell their customers (or other interested parties) something about that route. • Action tags – Communities set by and sent from a customer network, to influence the routing policies of the provider network – Alter route attributes on demand – Both globally and within own network – Control the import/export of routes
- 12. Informational tags • Information communities typically focus on – Where the route was learned • AKA Geographic data (continent, country, region, city, etc in short geotag) – How the route was learned • AKA Relationship data (transit, peer, customer, internal, etc) – There is no other good way to pass on this data • This data is then used to make policy decisions – Either by you, your customer, or an unknown third party. – Exporting this data to the Internet can provide invaluable assistance to third party networks you may never even know about. This is usually a good thing for everyone.
- 13. Ways to encode Information • Encode simple arbitrary data – No standards, each network defines its own mapping • Which must be published somewhere like ASN description in IRR for others to use – Ex: Continent (1 = Asia, 2 = Africa, etc) – Ex: Relationship (1 = Transit, 2 = Public Peer, etc) • Standards based encoding – Ex: ISO 3166 encodes Country Codes into 2 digits
- 14. Providing information • As always, the exact design decision depends on specific network and footprint. • Networks in only a few major cities may want to focus on enumerating those cities in a short list. • Networks in a great number of cities may want to focus on regional aggregation specific to their scope. • Plan for the future! – Changing community design after it is already being used by customers may prove impossible.
- 15. Practical Use of Informational Tags • Make certain that Informational Tags from your Action Tags can easily be distinguished • Ex: Make Informational Tags always 5 characters in length, and action tags to be 4 characters or less. • This allow to easily match Info tags: “10102:.{5}” • Filter communities from neighbors – None is allowed to send Informational tags, these should only be set by Service Provider, and these should be stripped from all BGP neighbors (customers, transits, peers, etc). – Otherwise there is a massive security problem.
- 16. A simple approach towards providing information • For example: 10102:TCCCP – T Type of Relationship – C Continent Code – CC Country Code – P POP Code • The community 10102:21021 could be parsed as: – Public Peer – Asia – Singapore – Equinix
- 17. Definitions - Types • Type of routes – 1XYYP – Transit – 2XYYP – Public Peer – 3XYYP – Private Peer – 4XYYP – Customer – 5XYYP – Internal
- 18. Definitions (Contd) • Continents – T0YYP – Asia – T1YYP – Africa – T2YYP – Europe – T3YYP – North America – T4YYP – South America – T5YYP – Australia – T6YYP – Antarctica
- 19. Definitions (Contd) • Countries – T001P – Bangladesh – T002P – Singapore – T201P – United Kingdom – T202P – France – So on ..
- 20. Definitions (Contd) • PoP – T0011 – Central NOC – T0021 – Singapore Global Switch – T0022 – Singapore Equinix – T2011 – United Kingdom Telehouse North – T3011 – United States TelX – So on ..
- 21. Let’s start geoconfiguring!! router bgp 10102 neighbor x.x.x.x remote-as 58656 neighbor x.x.x.x description bdHUB @Telx NYC neighbor x.x.x.x route-map as58656-in in neighbor x.x.x.x send-community ! route-map as58656-in permit 10 set community 10102:43011
- 22. References 1. Using Communities for Multihoming ( http://bgp4all.com/ftp/isp-workshops/BGP%20Presentations/09- BGP-Communities.pdf) 2. BGP Techniques for Internet Service Providers – Philip Smith 3. BGP Communities: A guide for Service Providers – Richard A. Steenbergen & Tom Scholl