Next Generation IPNext Generation IP< IPv6 >< IPv6 >

National Dong Hwa UniversityDirector of Computer Center

Han-Chieh Chao趙涵捷

下一代網際網路協定下一代網際網路協定

OverviewOverview

• Limitations of current Internet Protocol (IP)• IPv6 addressing• IPv4/IPv6 Transition• IPv6 features

– Autoconfiguration– IPSec– QoS

• IPv6 Mobility Support• Summary

Internet GrowthInternet Growth

Internet GrowthInternet Growth

Growing PainsGrowing Pains

• Depletion of IP address ( between 2005 and 2001 )

• Explosion of Routing Tables ( routing table explosion will condemn the internet

even sooner than the exhaustion of network addresses )

IPv4 AddressesIPv4 Addresses

• Example: 203.64.105.100=1100 1011:0100 0000:0110 1001:0110 0100

(32 bits) = CB:40:69:64• Maximum = 232 = 4 Billion• Class A Network: 15 Million nodes• Class B Network: 64,000 nodes or less• Class C Network: 250 nodes or less

IPv4 Address (cont.)IPv4 Address (cont.)

• 127 Class A + 16,381 Class B + 2,097,151 Class C Network = 2,113,659 networks total

• Class B is most popular• 20% of Class B were assigned by 7/90 and

doubling every 14 months => Will exhaust by 3/94

• Question: Estimate how big will you become?Answer: more than 256!Class C is too small. Class B is just right.

How many address?How many address?

• Some believe 26 to 28 address per host• Safety margin => 1015 addresses• IPng Requirements => 1012 end systems and

109 networks. Desirable 1012 to 1015 networks

Address SizeAddress Size

• H Ratio = log10(number of objects)/available bits• 2n objects with n bits: H Ratio = log102 = 0.30103• French telephone moved from 8 to 9 digits at 107

households => H = 0.26 (assuming 3.3 bits/digit) • US telephone expanded area codes with 108

subscribers => H = 0.24 • SITA expanded 7-character address at 64k nodes

=> H = 0.14 (assuming 5 bits/char)

Address Size (cont.)Address Size (cont.)

• Physics/space science net stopped at 15000 nodes using 16-bit addresses => H = 0.26

• 3 Million Internet hosts currently using 32-bit addresses => H = 0.20 => A few more years to go

• The enormous growth of Internet.

• The Address space is running out in IPv4 (32 bits).

• Routing tables are exploding.• The lack of security at the net

work layer• Device Control – Smart

Homes• High Performance Networks• IP Based Cellular Systems• Connect everything over IP

• Several years of networking with TCP/IP had brought lessons and knowledge

• Lack of Mobility support • New Applications such as Real

Time Multimedia.• Networked Entertainment - yo

ur TV will be an Internet host• More Scalable Solution is

needed

IPv6 motivationIPv6 motivation

Internet Draft

Technically complete and stable?

Yes Proposed Standard (RFC)

Yes DraftStandard (RFC)Multiple

InteroperableImplemen-

tationsYes Internet

Standard (RFC)

Significant OperationalExperience?

Where in the standardization process is IPv6?

6ren, vBNS etc.GPRS, UMTS?

IPv6 StandardizationIPv6 Standardization

Ipng long term solutionIpng long term solution

•1991: Work starts on next generation Internet protocols -- More than 6 different proposals were developed •1993: IETF forms IPng Directorate --To select the new protocol by consensus •1995: IPv6 selected -- Evolutionary (not revolutionary) step from IPv4 •1996: 6Bone started •1998: IPv6 standardized• Today: Initial products and deployments

IPv6 Main Features/FunctionalityIPv6 Main Features/Functionality

• expanded addressing and routing capabilities• support for extension headers and options• Simplified header format• quality of service capabilities• Auto-configuration• Multi-Homing• Class of Service/Multimedia support• support for authentication and privacy•Multicast (No more broadcast )• IPv4 , IPv6 Transition Strategy

0 bits 84 16 31

Ver IHL Total Length

Identifier Flags Fragment Offset

32 bit Source Address

32 bit Destination Address

24

Service Type

Options and Padding

Time to Live Header ChecksumProtocol

SuppressedRenamedRevised

IPv4 HeaderIPv4 Header20 Octets+Options : 13 fields, include 3 flag bits

Version Class Flow Label

Payload Length Next Header Hop Limit

128 bit Source Address

128 bit Destination Address

New

IPv6 HeaderIPv6 Header40 Octets, 8 fields

Major SimplificationsMajor Simplifications

• Assign a fixed format to all headers (40 bytes)• Remove the header checksum• Remove the hop-by-hop segmentation procedure• Built-in security

IPv6 AddressIPv6 Address

• 128 bits long. Fixed size • 2128 = 3.4×1038 addresses => 6.65×1023 addre

sses per m2 of earth surface• If assigned at the rate of 106/s, it would take

20 years • Expected to support 8×1017 to 2×1033 address

es 8×1017 => 1,564 address per m2 • Allows multiple interfaces per host• Allows multiple addresses per interface

Text Representation of ddressesText Representation of ddressesColon-Hex: 1080 : 0 : 0 : 0 : 8 : 800 : 200C : 417A “::” indicates multiple groups of 16-bits of zeros

Dot-Decimal : 203.64.105.100Can leave the last 32 bits in dot-decimal, :: 203.64.105.100

1080 :: 8 : 800 : 200C : 417A

The "::" can only appear once in an addressThe "::" can also be used to compress the leading and/or trailing zeros in an address

HierachyHierachy

3+5+16+16+8+32=80The remaining 48 bits define the particular system on the subnetwork.

IPv6 Address Models

• Allows unicast, multicast, anycast • Allows provider based, site-local, link-local

• 85% of the space is unassigned• Addresses have lifetime

– Valid and Preferred lifetime

Global Site-Local Link-Local

Local-Use AddressLocal-Use Address

• Link Local: Not forwarded outside the link,FE80::xxx

• Site Local: Not forwarded outside the site,FEC0::xxx

bits1111 1110 10 0 Interface ID

10 54 64

1111 1110 11 0 Subnet ID Interface IDbits3810 16 64

Multicast AddressMulticast Address

• T=0 => Permanent (well-known) multicast address, T=1 => Transient

• Scope: 1 Node-local, 2 Link-local, 5 Site-local,8 Organization-local, E Global, F Reserved

• Predefined: 1 => All nodes, 2 => Routers,

0 0 0 T

1111 1111 Flags Scope Group ID

4bits8bits 112bits4bits

Multicast Address (cont.)Multicast Address (cont.)• Link-local scope limits multicast to single Ethernet

Multicast Address (cont.)Multicast Address (cont.)• Organization-local scope limits multicast to organization boundary

Subnetwork Prefix : 5A01: 203 : 405 :607 : 809 :: /80

Anycast Address (the subnet-routAnycast Address (the subnet-router address)er address)

“Can any localrouter help me ”

Destination address : 5A01: 203 : 405 :607 : 809 : 0 : 0 : 0

• Workstation uses an anycast address to ask for help from any router.

Address PrefixesAddress Prefixes

Can specify a prefix by /length

Allocation Prefix Fraction of (binary) Address Space------------------------------- -------- -------------Reserved 0000 0000 1/256 (0::/8)Unassigned 0000 0001 1/256 (100::/8)Reserved for NSAP Allocation 0000 001 1/128 (200::/7)Reserved for IPX Allocation 0000 010 1/128 (400::/7)Unassigned 0000 011 1/128 (600::/7)Unassigned 0000 1 1/32 (800::/5)Unassigned 0001 1/16 (1000:/4)

IPv6 Address AllocationIPv6 Address Allocation

Allocation Prefix Fraction of (binary) Address Space------------------------------- -------- -------------Aggregatable Global Unicast Addresses 001 1/8 (2000::3)Unassigned 1111 0 1/32 (F000::/5)Unassigned 1111 10 1/64 (F800::/6)Unassigned 1111 110 1/128 (FC00::/7)Unassigned 1111 1110 0 1/512 (FE00::/9)Link Local Unicast Addresses 1111 1110 10 1/1024 (FE80::/10)Site Local Unicast Addresses 1111 1110 11 1/1024 (FEC0::/10)Multicast Addresses 1111 1111 1/256 (FF00::/8)

IPv6 Address Allocation (cont.)IPv6 Address Allocation (cont.)

IPv6 Extension HeadersIPv6 Extension Headers• IP options have been moved to a set of optional

Extension Headers• Extension Headers are chained together

IPv6 HeaderNext Header=TCPTCP Header

IPv6 HeaderNext Header=Routing

TCP HeaderRouting HeaderNext Header=TCP

IPv6 HeaderNext Header=Routing

TCP HeaderRouting HeaderNext Header=Fragment

Fragment HeaderNext Header=TCP

Next Header

Routing HeaderRouting Header

Next Header Routing Type Num. Address

Reserved Strict/Loose bit mask

Address 1

Address 2

Next Address

Address n

…..

Routing Header (cont.)Routing Header (cont.)

• Strict => Discard if Address[Next-Address] neighbor

• Type = 0 => Current source routing • Type > 0 => Policy based routing (later) • New Functionality: Provider selection, Host

mobility, Auto-readdressing (route to new address)

Address AutoconfigurationAddress Autoconfiguration• Allow plug and play• BOOTP and DHCP are used in IPv4 • DHCPng will be used with IPv6 • Two Methods: Stateless and Stateful• Stateless:

– A system uses link-local address as source and multicasts to "All routers on this link"

– Router replies and provides all the needed prefix info– All prefixes have a associated lifetime – System can use link-local address permanently if no route

r

Address Autoconfiguration (cont.)Address Autoconfiguration (cont.)

• Stateful: – Problem w stateless: Anyone can connect – Routers ask the new system to go DHCP server (b

y setting managed configuration bit) – System multicasts to "All DHCP servers" – DHCP server assigns an address

Automatic RenumberingAutomatic Renumbering

• Renumbering IPv6 Hosts is easy– Add a new Prefix to the Router– Reduce the Lifetime of the old prefix– As nodes depreciate the old prefix the new Prefix

will start to be used for new connections• Renumbering in IPv6 is designed to happen!• An end of ISP “lock in”!

– Improved competition

• Dual Stack : Providing complete support for both IPv4 and IPv6 in hosts and routers.

Transition Mechanism Transition Mechanism

DRIVER

IPv4 IPv6IPv4 IPv6

APPLICATION

TCP/UDP

This allows indefinite co-existence of IPv4 and IPv6, and gradual, app-by-app upgrades to IPv6 usage

IPv6 host IPv4 hostDual IP host

Transition Mechanism (cont.)Transition Mechanism (cont.)• IPv6 over IPv4 tunneling : Encapsulating IPv6 packets within

IPv4 headers to carry them over IPv4 routing infrastructures.

Entry Router

Leaving Router

IPv6packet IPv6

packet

IPv6packet

IPv4 header

Protocol number=41

IPv4Infrastructure

Encapsulate IPv6 packets inside IPv4 packets(or MPLS frames)any methods exist for establishing tunnels:

-- configured tunnels - manual-- automatic tunnels - IPv4 compatible addresses ::<ipv4>

Transition Mechanism (cont.)Transition Mechanism (cont.)

• IPv6-to-IPv4 (inter-domain, using IPv4 addr as IPv6 site prefix)

• IPv4-compatible IPv6 Addresses

96 bits 32 bits

|0000..............................00000000| IPv4 address |

Dest. :: 0102:0304 Dest. :: 0102:0304Dest. 1.2.3.4

Transition Mechanism (cont.)Transition Mechanism (cont.)

• IPv4-mapped IPv6 address

Dest. 1.2.3.4Dest. ::FFFF: 0102:0304 Dest. ::FFFF: 0102:0304

80 bits 16 bits

| 000………000 : 11….11: IPv4 |

Transition Mechanism (cont.)Transition Mechanism (cont.)

QoSQoS

• Class Field– Diff Serv Code Point will be used

– Can be used for distinguish between different traffic classes

• Flow label– Identifies streams that needs special handling

– Used by RSVP today

– Not fully defined yet

– Could be used for a deterministic hashkey to classify on L2-L7 -> Would make it easier to implement in Hardware

IPv6 SecurityIPv6 Security• Two headers in IPv6 that provides security - AH, ESP• AH - Authentication Header

– Provides source authentication– Integrity

• ESP - Encrypted Security Payload– Integrity– Authentication– Confidentiality

• Note: IPSec is exactly the same for IPv4 and IPv6 only that it was Taylor-made for IPv6.

• Advantages with IPsec– Network level security– Transparent to End-user– Open Standard

Mobile IPv6Mobile IPv6

• IPv6 Mobility is based on core features of IPv6– The base IPv6 was designed to support Mobility– Mobility is not an “Add-on” features

• All IPv6 Networks are IPv6-Mobile Ready• All IPv6 nodes are IPv6-Mobile Ready• All IPv6 LANs / Subnets are IPv6 Mobile Ready

• IPv6 Neighbor Discovery and Address Autoconfiguration allow hosts to operate in any location without any special support

Mobile IPv6 Mobile IPv6 (cont.)(cont.)

• No Foreign Agent– In a Mobile IP, an MN registers to a foreign node a

nd borrows its’ address to build an IP tunnel so that the HA can deliver the packets to the MN. But in Mobile IPv6, the MN can get a new IPv6 address, which can be only used by the MN and thus the FA no longer exists.

• More Scalable : Better Performance– Less traffic through Home Link – Less redirection / re-routing (Traffic Optimisation)

IPv6 Mobility SupportIPv6 Mobility SupportNo FA’s, ND, always Co-located Co addresses

mn.ndhu.tw

INTERNET

mit.us

for mn.ndhu.tw

Correspondend NodeHome AgentRouter

for mn.ndhu.tw atagent.mit.us

ndhu.tw

Gets an address trough ND

Improved PerformanceImproved Performance

• Faster processing time per IPv6 packet– Align on 64 bits boundary– Fewer Optional Headers (from 12 to 8)– Removed checksum

• Better designed for HW support• Scalable hierarchical address architecture

– Faster routing lookups– Smaller routing tables due to Hierarchical address architectu

re -> which make ip_forwarding faster and more efficient use of the memory

– Less routing traffic in the backbone -> which mean less load on the network

SummarySummary

• Streamlined Header Format• Flow Label• 128-bit Network Addresses• Elimination of Header Checksum• Fragmentation only by source Host• Extension Headers• Built-in-security