APNIC Information Management Director Sanjaya presents on Internet routing and addressing at AFSIG 2023, held online on 6 December 2023.

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Internet Routing and Addressing
4 December 2023
AFSIG 2023
Sanjaya, APNIC

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Outline
• How and why the Internet works
• Internet addressing
• Internet routing
• Challenges
• Maintaining a global, open, stable and secure Internet

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How and why the internet works

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The Internet
A conceptual view

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The Internet
A macroscopic view
https://www.caida.org/projects/as-core/

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Internet Number Resource
Global statistics
Delegated Advertised %
ASN 115,465 81,505 70%
IPv4 3,685,795,960 3,048,947,712 83%
IPv6 1,909,541,552,717,830 209,615,924,006,929 11%
https://resources.potaroo.net/iso3166/ip-distrib.xls

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AS interconnection in Afghanistan
https://rex.apnic.net/as-interconnections?economy=AF
Afghan Wireless Communication Company
Neda Telecommunications

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AS interconnection in Pakistan
https://rex.apnic.net/as-interconnections?economy=PK

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Internet addressing

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The Internet Protocol
• A set of rules and conventions that govern how data packets should be formatted, transmitted, routed,
and received over a computer network
• There are 2 versions: IPv4 and IPv6
https://en.wikipedia.org/wiki/Internet_Protocol_version_4 https://en.wikipedia.org/wiki/IPv6_packet
Optional extension header

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Scaling up IPv4
• IPv4 is a 32-bit address system, giving a theoretical
maximum of 4,294,967,296 (~4.3 billion) addresses. This is
not enough to uniquely identify the 29.3 billion estimated
devices connected to the Internet in 2023
• Network Address Translation is the most deployed
technique to overcome this issue by using a combination of
private IPv4 addresses combined with port numbers to
share a single public IPv4 address among multiple devices.

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Scaling up with IPv6
• As a 128-bit addressing system, IPv6 has no shortage of
public IP addresses to uniquely identify every device
connected to the Internet
• It also adds improvements over IPv4 e.g.
– Simplified header
– Autoconfiguration
– Improved security
– Efficient routing and Multicast
– End-to-end visibility that wasn’t possible with IPv4 + NAT

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Internet routing

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Autonomous System Number (ASN)
• ASNs are identifiers assigned to autonomous systems,
which are networks or organizations that have control over
their own routing policies and represent a distinct routing
domain on the Internet. ASNs are used to uniquely identify
and differentiate these autonomous systems in the global
routing system.
• First used in inter-domain routing Exterior Gateway
Protocol, it helps organise the Internet into network with
separate routing policies.

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Scaling up the Internet with BGP
• Border Gateway Protocol (BGP) is responsible for scaling
up the Internet by providing a robust and scalable
mechanism for routing data traffic between different
autonomous systems (ASes). It allows:
– Interdomain routing
– Hierarchical routing
– Policy-based routing
– Route aggregation
– Multihoming
– Path selection etc.

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Challenges

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Routing challenges
• BGP was designed primarily for scalability and routing
functionality. It assumes a collaborative, trusted network
participants.
• Route hijacking (accidental or intentional) is now
prevalent
• Global routing table size keeps on growing, that requires
significant investment in engineering and hardware
resources
• Traffic efficiency through network peering are not widely
practiced in some economies and regions

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IP address challenges
• IPv4 and NAT are ‘too effective’ that it reduced motivation to
adopt IPv6
• Shortage of IPv4 address has led to increasing cost of
getting it through transfer market or leasing
• IPv6 skills and knowledge still need to be developed
• Complexity in running dual stack IPv4 & IPv6 networks
during transition

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Maintaining a global, open, stable
and secure Internet

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Challenges can be overcome if
• Network operators adopt best practices in routing, address
management and security
– Routing best practices
• Route aggregation
• Accurate published routing information (IRR)
• Route monitoring etc.
– Address management best practices
• Public vs Private address usage
• Accurate published Whois information
– Security best practices
• MANRS
• RPKI etc.

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Where to learn Internet best practices
• APNIC Academy
• APRICOT & APNIC Conferences
• Network Operators Group meetings and mailing lists
• Fellowships provided by various organisations and events
– APRICOT, APNIC, APNIC Foundation, ICANN, IETF, ISOC etc.
• Online communities