IPv6 History, Principles, Addressing, Plug and Play, Routing, Facts and Myths, Migration ...

401 Pages·2012·3.55 MB·English

IPv6
IPv6 History, Principles, Addressing, Plug and Play,
Routing, Facts and Myths,
Migration & Transition Ideas
Agenda
•
History
– The initial problem in the 1990s
– The first decade (decision and prototyping)
– The second decade (maturity level)
•
IPv6
•
ICMPv6 and Plug&Play
•
Routing
•
Transition
•
Miscellaneous
©2012, D.I. Lindner IPv6, v4.7 2
The Internet at 1990 (1)
•
Only classful IP addresses (32 bit) were used
– A, B, C (unicast), D (multicast), E (experimental)
– There are only
• 126 class A nets with 16.777.214 hosts
• 16.384 class B nets with 65.534 hosts
• 2.097.152 class C nets with 254 hosts
•
In order to communicate over the Internet
– You have to use an official IP address range assigned by
your ISP or Local/Regional Internet Registry (RIR) for all
your IP systems
– This could be only a class A or B or C address range
•
Subnetting was used
– To divide a given class A, B or C address into subnets in
order to structure your local IP network with IP routers
©2012, D.I. Lindner IPv6, v4.7 3
Review: IP Address Classes / Subnetting
8 16 24 32
Class A 0 Net-ID Host-ID
Class B 1 0 Net-ID Host-ID
Class C 1 1 0 Net-ID Host-ID
Class D 1 1 1 0 Multicast Addresses
Class E 1 1 1 1 Experimental Usage
Class B with Subnet mask (255.255.255.0)
1 0 Net-ID Host-ID
Net-ID Subnet-ID Host-ID
First octet rule:
- class A range: 1-126 - class B range: 128-191
- class C range: 192-223 - class D range: 224-239
©2012, D.I. Lindner IPv6, v4.7 4
Review: ISP Routing Updates with Classful Behavior
ISP Domain
Internet
192.32.7.0 192.32.8.0
192.32.1.0
Routing Updates
192.32.0.0 / 24 192.32.6.0
192.32.5.0
192.32.1.0 / 24
192.32.2.0 192.32.4.0
192.32.2.0 / 24
192.32.3.0 / 24
Unused addresses
192.32.4.0 / 24
192.32.5.0 / 24
192.32.6.0 / 24
192.32.3.0
………….
192.32.14.0 / 24
192.32.9.0 192.32.10.0
192.32.15.0 / 24
©2012, D.I. Lindner IPv6, v4.7 5
The Internet at 1990 (2)
•
Address classes were inflexible
– IP address with 232 bits
• 4.294.967.296 IP hosts could be distinguished in theory
– minus Class D and E (536.870.912)
– minus Net 0 and 127 (33.554.432)
– minus RFC 1918 (17.891.328)
• result: 3.706.650.624 usable addresses
– Class B to large and Class C to small for many companies
– Constant subnet masks wasted a lot of (unused) addresses
•
Exponential growth of Internet connected devices
– Prediction of the exhaustion of IPv4 addresses by 2005-2011
•
But the real problem was
– Class B addresses were nearly exhausted
• Prediction of the exhaustion of IPv4 class B addresses by 1994
– Routing table explosion at Internet core routers
• Caused by assigning multiple class C addresses for bigger companies
©2012, D.I. Lindner IPv6, v4.7 6
BGP Routing Table Growth – Internet Core
Growth without CIDR + Private Addresses + NAT)
Actual Growth Source: http://en.wikipedia.org/wiki/Border_Gateway_Protocol
©2012, D.I. Lindner IPv6, v4.7 7
The Way to IPng / IPv6 History (2)
• The Need for a new IP was identified
• November 1991
– Routing and Addressing (ROAD) workgroup formed
• March 1992
– ROAD report
• Do CIDR (Classless InterdomainRouting)
• Issue a call forIPng(next generation) proposals
• CIDR, private IP addressing and network address translation (NAT) as temporary (short-term)
solution
– RFC 1518 An Architecture for IP Address Allocation with CIDR (Status: HISTORIC)
– RFC 1519 Classless Inter-Domain Routing (CIDR): an Address Assignment and Aggregation Strategy (obsoleted by
RFC 4632) (Status: PROPOSED STANDARD)
– RFC 4632 Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan
(Obsoletes RFC1519) BCP0122)
• http://www.potaroo.net/ (BGP table, CIDR report – Geoff Huston)
– RFC 1631 “The IP Network Address Translator (NAT)” may 1994 (obsoleted by RFC 3022) (Status:
INFORMATIONAL)
– RFC 3022 Traditional IP Network Address Translator (Traditional NAT) (Obsoletes RFC1631) (Status:
INFORMATIONAL)
– RFC 1918 “Address Allocation for Private Internets” February 1996 (Status: BCP0005)
©2012, D.I. Lindner IPv6, v4.7 8
Classless Inter-Domain Routing (CIDR)
– Address assignment and aggregation (= route
summarization) strategy for blocks of networks with
contiguous addresses
– Creative IP address allocation
• addressing plan for class C addresses by continents
• provider based addressing strategy
– Classless routing (prefix, length)
• Classful routing protocols advertize only net-id (= prefix) of
networks but no subnetmask
– Usage of VLSM (Variable Length Subnet Mask)
• For better usage of address space
– Supernetting of class C network numbers blocks
©2012, D.I. Lindner IPv6, v4.7 9
ISP Routing Updates with Classless Behavior
(Route Summarization with Supernetting), VLSM
ISP Domain
Internet
192.32.7.0 / 24 192.32.8.0 / 24
192.32.1.0 / 30
.2
.1
Routing Update .9
.17
.5
192.32.0.0 / 20 192.32.6.0 / 24
192.32.1.4 /30
(255.255.240.0)
192.32.1.8 / 30
192.32.1.16 / 30
.10
.18
.6
192.32.1.12 / 30
.13
.14
192.32.9.0 / 24 192.32.15.0 / 24
©2012, D.I. Lindner IPv6, v4.7 10