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RFC role and IPv6 addressing

Short answer

RFCs are permanent, free, open specifications enabling interoperability and global Internet distribution. IPv6 has 128-bit addresses, written in eight colon-separated hex groups (shortenable with ::), prefix/length format. Types: global unicast (2000::/3), link-local (fe80::/10), multicast (ff00::/8), loopback (::1/128); no broadcast. Interface IDs can use EUI-64 from MAC; SLAAC or DHCPv6 for config; sites get /48.

How has RFC helped in the development and distribution of internet? Write about IPv6 addressing in detail.

Role of RFCs in the development and distribution of the Internet

A Request for Comments (RFC) is a numbered, public document that specifies an Internet protocol or practice. RFCs helped the Internet grow in these ways:

  1. Open standards: every protocol (TCP RFC 793, IP RFC 791, HTTP, SMTP RFC 5321, DNS RFC 1035, IPv6 RFC 8200) is described in a free public document, so any vendor can build compatible products.
  2. Interoperability: equipment from different manufacturers works together because all follow the same specification.
  3. Community review: the "request for comments" process lets engineers worldwide review and improve a design before it becomes a standard.
  4. Easy distribution: RFCs are freely available online, so developers in any country, including Nepal, can implement the protocols without licence fees.
  5. Documentation of history and practice: informational, BCP and experimental RFCs record operational experience and guide new work.
  6. Stable versioning: RFC numbers never change; updates are new RFCs, so implementers always know which version they follow.

IPv6 addressing in detail

IPv6 (RFC 8200 for the protocol, RFC 4291 for addressing) uses 128-bit addresses, giving about 3.4 x 10^38 addresses.

Notation: eight groups of four hexadecimal digits separated by colons, e.g. 2001:0db8:0000:0000:0000:0000:0000:0001.

Short-hand rules:

  • Leading zeros in a group may be dropped: 2001:db8:0:0:0:0:0:1
  • One run of all-zero groups may be replaced by :: (only once): 2001:db8::1

Structure: prefix/length, like CIDR, e.g. 2001:db8:abcd:12::/64. A typical global unicast address is a 48-bit site prefix, a 16-bit subnet ID and a 64-bit interface ID.

|    48 bits    | 16 bits | 64 bits        |
| Global prefix |Subnet ID| Interface ID   |

Address types

TypePrefixPurpose
Global unicast2000::/3One-to-one, routable on the Internet
Link-localfe80::/10Used on one link only, auto-configured
Unique localfc00::/7Private use inside an organisation
Multicastff00::/8One-to-many, replaces broadcast
Anycastfrom unicast rangeSame address on many nodes; nearest one answers
Loopback::1/128Local host
Unspecified::/128Used before an address is assigned

There is no broadcast in IPv6.

Interface ID and auto-configuration: the 64-bit interface ID can be built from the MAC address by EUI-64: split the MAC, insert ff:fe in the middle and flip the 7th bit. For MAC 00:1A:2B:3C:4D:5E the interface ID is 021A:2BFF:FE3C:4D5E. Hosts get addresses by SLAAC (Router Advertisement gives the prefix) or DHCPv6. Neighbour Discovery (ICMPv6) replaces ARP.

Allocation: IANA gives RIRs /12 blocks, RIRs give ISPs /32, and ISPs give each customer site a /48 (or /56 for homes).

✓ Answer checked by Claude Opus 5.5 (high effort)

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