Seminar "Akamai DNS: Providing Authoritative Answers to the World’s Queries"

Presentation of the paper "Akamai DNS: Providing Authoritative Answers to the World’s Queries", presented at the Networking seminar at DCC/UFMG 2021/01.

Presentation (PT-BR): https://www.youtube.com/watch?v=1e5gTxnr-m8
Original paper: https://www.akamai.com/it/it/multimedia/documents/technical-publication/akamai-dns-providing-authoritative-answers-to-the-worlds-queries.pdf

Transcript

1. Lucas Bleme Akamai DNS: Providing Authoritative Answers to the World’s Queries
2. Authors Kyle Schomp, Onkar Bhardwaj, Eymen Kurdoglu, Mashooq Muhaimen and Ramesh K. Sitaraman SIGCOMM '20 - Annual conference of the ACM Special Interest Group on Data Communication on the applications, technologies, architectures, and protocols for computer communication
3. Agenda Problem (motivation) Architecture Anycast Resiliency Attack Resiliency Related Works Final Evaluation
4. Problem: Akamai DNS Recursive resolver DNS Root nameserver DNS TLD nameserver Authoritative Nameserver mywebsite.com
5. Problem: Akamai DNS
6. • High Available network (24/7) • Resilient authoritative DNS • Scalable DNS queries: serving 15-20% of all web traffic • Reconfigurable network Erik Nygren, Ramesh K Sitaraman, and Jennifer Sun. 2010. The Akamai Network: A Platform for High-Performance Internet Applications. ACM SIGOPS Operating Systems Review 44, 3 (2010), 2–19. Problem: Akamai DNS
7. Overall architecture Point of Presence
8. Anycast prefixes (A B C D E F G …) from different PoPs A E F B C G F B A D C E D A B G F A Point of Presence
9. ex1.com delegated to A B C D E F A E F B C G F B A D C E D A B G F A Point of Presence
10. ex1.com can be still resolved by F A E F B C G F B A D C E D A B G F A Point of Presence
11. Akamai DNS architecture
12. Single PoP architecture
13. • Failover withdrawing and advertising anycast prefixes Anycast resiliency
14. • Failover time < 1 sec. for 76% of measurements Anycast resiliency
15. • BGP update causes 200 msec difference between 2/21 PoPs. Anycast resiliency
16. • Traffic shift for single machine failures withdrawing IP anycast • Monitoring agents with limited server suspension permissions to prevent broad outages Anycast resiliency
17. • Uses input-delayed nameservers to prevent input-induced failures • Answer DNS queries with intentionally stale data ensuring that Akamai DNS remains available • Higher Multi-Exit Discriminator (MED) values prevent input-delayed NS to respond stale data Anycast resiliency
18. • No PoP supports more than 2 anycast cloud • Query scoring and prioritized processing • Overprovision bandwidth to avoid saturated links during volumetric attacks Attack resiliency
19. Attack resiliency
20. • Random subdomain attacks prevented using NXDOMAIN filters Attack resiliency
21. Related Work Matt Calder, Ashley Flavel, Ethan Katz-Bassett, Ratul Mahajan and Jitendra Padhye. Analyzing the Performance of an Anycast CDN. IMC '15: Proceedings of the 2015 Internet Measurement Conference. Sebastian Castro, Duane Wessels, Marina Fomenkov, and Kimberly Claffy. A Day at the Root of the Internet, ACM SIGCOMM Computer Communication Review 38, 5 (2008), 41–46. Erik Nygren, Ramesh K Sitaraman, and Jennifer Sun. 2010. The Akamai Network: A Platform for High-Performance Internet Applications. ACM SIGOPS Operating Systems Review 44, 3 (2010), 2–19.
22. Final Evaluation Guiding design principles through experiments lead to a robust authoritative DNS system. Avoiding single points of failure, using automated mitigation strategies and continuing to operate in a degraded state instead of stopping operating at all are the key design principles that allowed such a resilient and high available DNS system.
23. Thank you! https://speakerdeck.com/andreybleme Lucas Bleme andreybleme@ufmg.br Akamai DNS: Providing Authoritative Answers to the World’s Queries