UPM, May, 2003studies.ac.upc.edu/doctorat/NGN/GIS2003_TutorialIPv6_2.pdf · Need for renumbering techniques Need for new multihoming techniques Minimal modifications to dynamic routing

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IPv6 Tutorial IPv6 Tutorial –– Routing & Addressing in IPv6Routing & Addressing in IPv6© DIT© DIT--UPM, May, 2003UPM, May, 2003 11

David Fernández ([email protected] Fernández ([email protected]))DptoDpto. . IngenieríaIngeniería de de SistemasSistemas TelemáticosTelemáticos

Universidad Universidad PolitécnicaPolitécnica de Madridde Madrid

Global IPv6 Summit Global IPv6 Summit –– Madrid, May 2003Madrid, May 2003

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ContentsContents

�� Addressing ModelAddressing Model�� Routing ModelRouting Model�� New Address Assignment Policy New Address Assignment Policy �� Routing Header Routing Header �� Network RenumberingNetwork Renumbering�� MultihomingMultihoming�� Dynamic Routing ProtocolsDynamic Routing Protocols

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IPv6 Addressing Model (I)IPv6 Addressing Model (I)

�� Defined in RFC 3513: IP Version 6 Addressing Architecture Defined in RFC 3513: IP Version 6 Addressing Architecture �� Addresses of 128 bits Addresses of 128 bits

more than 10more than 1038 38 possible addressespossible addressesmore than 1500 addresses per mmore than 1500 addresses per m22 having into account having into account hierarchical assignment losses hierarchical assignment losses ––and being pessimisticand being pessimistic-- (C. (C. HuitemaHuitema))

�� Addresses are assigned to interfaces Addresses are assigned to interfaces Multiple addresses per interfaceMultiple addresses per interface

�� Subnet prefix associated with one link:Subnet prefix associated with one link:Multiple subnet prefixes may be assigned to a link. Multiple subnet prefixes may be assigned to a link.

�� Addresses have scope Addresses have scope LinkLink--LocalLocalSiteSite--Local (being deprecated)Local (being deprecated)GlobalGlobal

Global

Site-Local

Link-Local

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IPv6 Addressing Model (II)IPv6 Addressing Model (II)

�� Address Structure:Address Structure:IPv6 Address = Prefix + Interface IdIPv6 Address = Prefix + Interface Id

�� Separation of “who you are” from “where you are Separation of “who you are” from “where you are connected to”connected to”

Prefix: depends on routing topologyPrefix: depends on routing topologyInterface Id: identifies a nodeInterface Id: identifies a node

�� New Anycast addresses:New Anycast addresses:UnicastUnicast: from one host to another: from one host to anotherMulticastMulticast: from one to all belonging to a group: from one to all belonging to a groupAnycastAnycast: from one to the nearest belonging to a : from one to the nearest belonging to a groupgroup

�� Broadcast disappears (Broadcast disappears (supersededsuperseded by by multicastmulticast))

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Text Representation of Addresses (I)Text Representation of Addresses (I)

�� Preferred form:Preferred form:X:X:X:X:X:X:X:X (X = 2 bytes written in hex.)X:X:X:X:X:X:X:X (X = 2 bytes written in hex.)

�� Example:Example:

3ffe:3328:4:3:250:4ff:fe5c:b3f43ffe:3328:4:3:250:4ff:fe5c:b3f4

�� Contiguous zeros can be eliminated:Contiguous zeros can be eliminated:FF01:0:0:0:0:0:0:43 = FF01::43FF01:0:0:0:0:0:0:43 = FF01::43

�� IPv4IPv4--compatible IPv6 addresses:compatible IPv6 addresses:

0:0:0:0:0:0:194.179.46.78 = ::194.179.46.780:0:0:0:0:0:194.179.46.78 = ::194.179.46.78

Prefix Interface Id

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Text Representation of Addresses (II)Text Representation of Addresses (II)

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�� Special addresses:Special addresses:0:0:0:0:0:0:0:1 0:0:0:0:0:0:0:1 -- LoopbackLoopback0:0:0:0:0:0:0:0 0:0:0:0:0:0:0:0 -- Unspecified AddressUnspecified Address

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�� Prefix representation (CIDR notation):Prefix representation (CIDR notation):3ffe:0000:0000:CD30:0000:0000:0000:0000/603ffe:0000:0000:CD30:0000:0000:0000:0000/603ffe::CD30:0:0:0:0/603ffe::CD30:0:0:0:0/603ffe:0:0:CD30::/603ffe:0:0:CD30::/60

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�� Prefix representation (CIDR notation):Prefix representation (CIDR notation):3ffe:0000:0000:CD30:0000:0000:0000:0000/603ffe:0000:0000:CD30:0000:0000:0000:0000/603ffe::CD30:0:0:0:0/603ffe::CD30:0:0:0:0/603ffe:0:0:CD30::/603ffe:0:0:CD30::/60

�� Literal Addresses in URLs (RFC 2732)Literal Addresses in URLs (RFC 2732)httphttp://[2001::4:://[2001::4:FEDC:BA98FEDC:BA98:7654:210]:80/:7654:210]:80/index.htmlindex.html

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IPv6 Assigned PrefixesIPv6 Assigned Prefixes�� Address type indicated by highAddress type indicated by high--order bits of the address order bits of the address

(formerly known as (formerly known as Format Prefix)Format Prefix)::

2000:/82000:/81/81/8001001Global UnicastGlobal Unicast(everything else)(everything else)

FF00::/8FF00::/8

FEC0::/10FEC0::/10

FE80::/10FE80::/10

PrefixPrefix

1/2561/2561111 11111111 1111MulticastMulticast

1/10241/10241111 1110 111111 1110 11SiteSite--LocalLocal

1/10241/10241111 1110 101111 1110 10LinkLink--LocalLocal

FractionFractionFPFPTypeType

�� Anycast addresses allocated from unicast prefixesAnycast addresses allocated from unicast prefixes�� Future specifications may redefine subFuture specifications may redefine sub--ranges of global unicast ranges of global unicast

space for other purposes:space for other purposes:implementations must treat all addresses that do not start implementations must treat all addresses that do not start with any of the abovewith any of the above--listed prefixes as global unicast addresses.listed prefixes as global unicast addresses.

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DNS Modifications for IPv6DNS Modifications for IPv6�� New DNS record types for IPv6:New DNS record types for IPv6:

AAAA recordAAAA record (quad A). Defined in RFC 1886. Equivalent to A (quad A). Defined in RFC 1886. Equivalent to A records for IPv4 but allowing 128 bits addressesrecords for IPv4 but allowing 128 bits addressesPTR recordPTR record: for inverse resolutions under ip6.arpa (ip6.int : for inverse resolutions under ip6.arpa (ip6.int initially) initially)

Example: to resolve Example: to resolve 4321:0:1:2:3:4:567:89ab 4321:0:1:2:3:4:567:89ab into a name, we ask for the into a name, we ask for the PTR record of:PTR record of:b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.ip6.arpa. ip6.arpa.

A6 record. A6 record. Defined in 2874. Stores IPv6 address following Defined in 2874. Stores IPv6 address following network hierarchy to simplify renumbering.network hierarchy to simplify renumbering.DNAME and Binary Labels recordsDNAME and Binary Labels records: to easy renumbering for : to easy renumbering for inverse resolution inverse resolution

�� AAAA preferred to A6 (RFC3363):AAAA preferred to A6 (RFC3363):A6, DNAME and Binary Labels need to be better understood A6, DNAME and Binary Labels need to be better understood before deploymentbefore deploymentMoved to experimental standardsMoved to experimental standards

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�� Main Problems:Main Problems:Shortage of addressesShortage of addressesRouting Table SizeRouting Table Size

Routing in IPv4Routing in IPv4

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BGP Table Size Evolution

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High Resources High Resources ComsumptionComsumption::•• CPUCPU•• MemoryMemory•• BandwidthBandwidth

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�� CIDRCIDR allowed to survive the first big crisis (92allowed to survive the first big crisis (92--95), 95), but, ¿will it be able to survive next years growth but, ¿will it be able to survive next years growth ((xDSLxDSL, mobile terminals, etc)?, mobile terminals, etc)?

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�� The answer is...... The answer is......

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�� The answer is...... The answer is...... IPv6!!

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Routing in IPv6 OutlineRouting in IPv6 Outline

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Routing in IPv6 OutlineRouting in IPv6 Outline�� Main goal: Main goal: SCALABILITYSCALABILITY

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Routing in IPv6 OutlineRouting in IPv6 Outline�� Main goal: Main goal: SCALABILITYSCALABILITY�� Similar to IPv4 routing with CIDRSimilar to IPv4 routing with CIDR

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LongestLongest--prefix matchprefix match

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LongestLongest--prefix matchprefix match�� Strongly hierarchicalStrongly hierarchical

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Need for renumbering techniquesNeed for renumbering techniques

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Need for renumbering techniquesNeed for renumbering techniquesNeed for new multihoming techniques Need for new multihoming techniques

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�� Minimal modifications to dynamic routing protocols Minimal modifications to dynamic routing protocols (OSPF, RIP, IS(OSPF, RIP, IS--IS, BGP, etc) in order to work with IS, BGP, etc) in order to work with IPv6 (address formats).IPv6 (address formats).

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�� Improved source routing option (Routing Header). Improved source routing option (Routing Header). Used for:Used for:

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Provider SelectionProvider Selection

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Provider SelectionProvider SelectionMobilityMobility

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IPv6 Routing ModelIPv6 Routing Model

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IPv6 Routing ModelIPv6 Routing Model�� Initially defined in RFC 2374: An IPv6 Initially defined in RFC 2374: An IPv6 AggregatableAggregatable Global Global

Unicast Address Format, but important changes in progress:Unicast Address Format, but important changes in progress:RFC 2374 and TLA/NLA structure being made historicRFC 2374 and TLA/NLA structure being made historic

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�� Strictly hierarchical with three levels: Strictly hierarchical with three levels: Public TopologyPublic Topology: providers and exchanges that offer Internet : providers and exchanges that offer Internet transit services.transit services.Site TopologySite Topology: local topology of a site that does not offer transit : local topology of a site that does not offer transit services to nodes external to its organization.services to nodes external to its organization.Interface IdentifierInterface Identifier: unique identifier assigned to any interface : unique identifier assigned to any interface connected to Internet.connected to Internet.

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�� Main objective: Main objective: SCALABILITYSCALABILITY

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�� Main objective: Main objective: SCALABILITYSCALABILITY�� Initially defined for prefix 2000::/3 (addresses beginning by Initially defined for prefix 2000::/3 (addresses beginning by

2XXX:... and 3XXX:...)2XXX:... and 3XXX:...)but now being extended to all Global Unicast prefixesbut now being extended to all Global Unicast prefixes

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Public TopologyPublic Topology

X1, X2: Exchanges (NAP, FIX, etc)P1, P2, P3, P4: Long-haul ProvidersP5, P6: Providers

X1, X2: Exchanges (NAP, FIX, etc)P1, P2, P3, P4: Long-haul ProvidersP5, P6: Providers

P1P1

P5P5Site ASite A

P2P2

P3P3

P4P4

Site BSite B

Site DSite D

Site ESite E Site FSite F

Site CSite CP6P6

X1X1 X2X2

IX Assigned Addressing Model

Provider Assigned Addressing Model

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Routing Model: SummaryRouting Model: Summary

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�� Hierarchical modelHierarchical model: addresses depend strictly of : addresses depend strictly of network topologynetwork topology

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�� Two types of Two types of AggregationAggregation::Per ProviderPer Provider: addresses depend on the : addresses depend on the provider we are connected toprovider we are connected toPer ExchangePer Exchange: addresses depend on the : addresses depend on the Exchange we are connected toExchange we are connected to

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�� Two types of Two types of AggregationAggregation::Per ProviderPer Provider: addresses depend on the : addresses depend on the provider we are connected toprovider we are connected toPer ExchangePer Exchange: addresses depend on the : addresses depend on the Exchange we are connected toExchange we are connected to

�� ConsequencesConsequences: : If we change Provider or Exchange, we need If we change Provider or Exchange, we need to to RENUMBERRENUMBER our network. (The same our network. (The same happens if the provider of our provider happens if the provider of our provider changes)changes)IPv4 IPv4 multihommingmultihomming techniques not allowed techniques not allowed

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�� Global Global AggregatableAggregatable Unicast Addresses (RFC2374):Unicast Addresses (RFC2374):

Public Topology Prefix (48 bits)Public Topology Prefix (48 bits)

NLA/TLA Addressing SchemeNLA/TLA Addressing Scheme

FP

128 bits

Site Topology (80 bits)Site Topology (80 bits)

TLA ID RESV NLA ID SLA ID Interface ID3 b 13 bits 24 bits 16 bits 64 bits8 bits

FPFP Format Prefix (001)Format Prefix (001)TLA IDTLA ID TopTop--Level Aggregation IdentifierLevel Aggregation IdentifierRESVRESV Reserved (to enlarge TLA o NLA)Reserved (to enlarge TLA o NLA)NLA IDNLA ID NextNext--Level Aggregation IdentifierLevel Aggregation IdentifierSLA IDSLA ID SiteSite--Level Aggregation IdentifierLevel Aggregation IdentifierInterface IDInterface ID Interface Identifier (EUIInterface Identifier (EUI--64)64)

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�� Global Global AggregatableAggregatable Unicast Addresses (RFC2374):Unicast Addresses (RFC2374):

Public Topology Prefix (48 bits)Public Topology Prefix (48 bits)

NLA/TLA Addressing SchemeNLA/TLA Addressing Scheme

FP

128 bits

Site Topology (80 bits)Site Topology (80 bits)

TLA ID RESV NLA ID SLA ID Interface ID3 b 13 bits 24 bits 16 bits 64 bits8 bits

FPFP Format Prefix (001)Format Prefix (001)TLA IDTLA ID TopTop--Level Aggregation IdentifierLevel Aggregation IdentifierRESVRESV Reserved (to enlarge TLA o NLA)Reserved (to enlarge TLA o NLA)NLA IDNLA ID NextNext--Level Aggregation IdentifierLevel Aggregation IdentifierSLA IDSLA ID SiteSite--Level Aggregation IdentifierLevel Aggregation IdentifierInterface IDInterface ID Interface Identifier (EUIInterface Identifier (EUI--64)64)

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New Addressing SchemeNew Addressing Scheme

�� Basic unicast address format defined in “IPv6 Global Basic unicast address format defined in “IPv6 Global Unicast Address” <draftUnicast Address” <draft--ietfietf--ipv6ipv6--unicastunicast--aggraggr--v2v2--02.txt>, Feb 200302.txt>, Feb 2003

�� NLA/TLA disappearsNLA/TLA disappears�� SLA maintained under “Subnet ID” nameSLA maintained under “Subnet ID” name�� Further structure left to regional registriesFurther structure left to regional registries

“…allocation of IPv6 addresses is related to policy and to “…allocation of IPv6 addresses is related to policy and to the stewardship of the IP address space and routing table the stewardship of the IP address space and routing table size which the size which the RIRsRIRs have been managing for IPv4” have been managing for IPv4”

Global Routing Prefix Subnet ID Interface ID

n bitsn bits 6464--n bitsn bits 64 bits64 bits

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Address Delegation HierarchyAddress Delegation HierarchyIANAIANAIANA

RIRRIRRIR RIRRIRRIR

NIRNIRNIR

ISP/LIRISP/LIRISP/LIR ISP/LIRISP/LIRISP/LIR

EU (ISP)EU (ISP)EU (ISP) EUEUEU EUEUEU

Regional Internet Registries:• ARIN• RIPE• APNIC• LACNIC• AFRINIC

National Internet Registries(APNIC region)

Local Internet Registries(ISP’s)

End Users

Source: Paul Wilson, APNIC

Allocates to

Assigns to

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RIRsRIRs IPv6 Address Allocation and IPv6 Address Allocation and Assignment PolicyAssignment Policy

�� Jointly defined by ARIN, APNIC and RIPE Jointly defined by ARIN, APNIC and RIPE see RIPEsee RIPE--267, January 2003267, January 2003

�� Based on RFC recommendations 3177 from IETFBased on RFC recommendations 3177 from IETF�� Definition of policies for the assignment and allocation of globDefinition of policies for the assignment and allocation of globally ally

unique IPv6 addresses to Internet Service Providers (ISPs) and unique IPv6 addresses to Internet Service Providers (ISPs) and other organizationsother organizations

considered to be an interim policyconsidered to be an interim policyIt will be reviewed in the future, subject to greater experienceIt will be reviewed in the future, subject to greater experience in in the administration of IPv6.the administration of IPv6.

�� Goals:Goals:Uniqueness, Registration, Aggregation, Conservation, Fairness, Uniqueness, Registration, Aggregation, Conservation, Fairness, Minimized overhead Minimized overhead AggregationAggregation is the most importantis the most important

�� Main design decision: fixed prefixes boundaries (/32, /48, /64)Main design decision: fixed prefixes boundaries (/32, /48, /64)

0 /64 127

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Policies for Allocations and Assignments Policies for Allocations and Assignments �� Minimum allocation size by Minimum allocation size by RIRsRIRs: : /32/32�� ALLOCATIONALLOCATION to to LIRsLIRs (ISP): (ISP):

Initially:Initially: /32/32If they plan for making at least 200 /48 assignments to other If they plan for making at least 200 /48 assignments to other organizations within two years. organizations within two years.

Subsequent /32 allocations when justified (HDSubsequent /32 allocations when justified (HD--ratio of 0.8)ratio of 0.8)�� ASSIGNATIONASSIGNATION to End Sites: to End Sites:

In general: In general: /48 /48 (16 bits for end(16 bits for end--site subnets)site subnets)except for very large subscribers (multiple /48 when justified)except for very large subscribers (multiple /48 when justified)Same allocation for home network subscribers (onSame allocation for home network subscribers (on--demand or demand or alwaysalways--on connections), small and large enterprises on connections), small and large enterprises

when known that only one subnet is needed by design: when known that only one subnet is needed by design: /64/64Ex: Mobile networks, such as vehicles or mobile phones with an Ex: Mobile networks, such as vehicles or mobile phones with an additional network interfaceadditional network interface

when known that only one device is connecting: when known that only one device is connecting: /128 /128 Ex: PPP connectionEx: PPP connection

�� REGISTRATION:REGISTRATION:Address allocations must be register in a database Address allocations must be register in a database accessible by accessible by RIRsRIRs

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Example: Home ADSL networkExample: Home ADSL network

�� Requirements: Requirements: two /64 prefixes for LAN two /64 prefixes for LAN and WLANand WLAN

�� Assigning aAssigning a /48/48 means means assigning 65536 prefixes!! assigning 65536 prefixes!!

Internet

ADSL

LAN WLAN

Router

2001:9000:40::/48

2001:9000:40:1::/64

2001:9000:40:0::/64

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Internet

ADSL

LAN WLAN

Router

2001:9000:40::/48

2001:9000:40:1::/64

2001:9000:40:0::/64

�� Are we wasting addresses?Are we wasting addresses?

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Internet

ADSL

LAN WLAN

Router

2001:9000:40::/48

2001:9000:40:1::/64

2001:9000:40:0::/64

�� Are we wasting addresses?Are we wasting addresses?�� There are more than 35 There are more than 35

trillions of trillions of /48/48 prefixesprefixes

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Internet

ADSL

LAN WLAN

Router

2001:9000:40::/48

2001:9000:40:1::/64

2001:9000:40:0::/64


trillions of trillions of /48/48 prefixesprefixes�� Even taking into account Even taking into account

assignation losses:assignation losses:At least 178.000 millions of At least 178.000 millions of /48/48prefixes availableprefixes available

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Internet

ADSL

LAN WLAN

Router

2001:9000:40::/48

2001:9000:40:1::/64

2001:9000:40:0::/64


trillions of trillions of /48/48 prefixesprefixes�� Even taking into account Even taking into account

assignation losses:assignation losses:At least 178.000 millions of At least 178.000 millions of /48/48prefixes availableprefixes available

�� Advantages of fixed boundary:Advantages of fixed boundary:Easy change of ISPEasy change of ISPEasy renumberingEasy renumberingEasy multihoming Easy multihoming Easy growth of subscriber Easy growth of subscriber networks networks No need to judge sites' needs No need to judge sites' needs

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Routing HeaderRouting Header

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�� Allows to modify routing decisions made by routers Allows to modify routing decisions made by routers (Source Routing):(Source Routing):

The sender of a datagram can specify a list of The sender of a datagram can specify a list of addresses to “visit” in the way to the destinationaddresses to “visit” in the way to the destination

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�� Very similar to IPv4’s option Very similar to IPv4’s option Loose/Strict Source Loose/Strict Source Routing Routing ......

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�� …but without its important limitations (header size, …but without its important limitations (header size, inefficiencies, etc)inefficiencies, etc)

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�� …but without its important limitations (header size, …but without its important limitations (header size, inefficiencies, etc)inefficiencies, etc)

�� Main applications:Main applications:Provider Selection (combined with anycast Provider Selection (combined with anycast addresses)addresses)MobilityMobility

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�� Format:Format:

........

Address 1Address 1

Address 2Address 2

Address NAddress N

NHNH HdrHdr Ext LenExt Len RT=0RT=0 Segments LeftSegments Left

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�� Format:Format:

........

Address 1Address 1

Address 2Address 2

Address NAddress N

NHNH HdrHdr Ext LenExt Len RT=0RT=0 Segments LeftSegments Left

�� Differences with IPv4:Differences with IPv4:Datagram destination Datagram destination

address is substituted address is substituted by the next address in by the next address in the list.the list.

Responses to Responses to datagrams with RH datagrams with RH must include the same must include the same RH but with the list of RH but with the list of addresses inverted.addresses inverted.

Strict/loose optionStrict/loose optioneliminatedeliminated

�� RH security issues being RH security issues being discusseddiscussed

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Anycast AddressesAnycast Addresses

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Anycast AddressesAnycast Addresses�� Anycast addresses are Anycast addresses are unicast unicast

addresses addresses assigned to several assigned to several interfaces (of different nodes interfaces (of different nodes typically)typically)

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�� A packet sent to an A packet sent to an anycastanycast address address should reach should reach the nearest interface the nearest interface with that address assignedwith that address assigned

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�� For example: For example: Subnet Router Subnet Router Anycast AddressAnycast Address

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Subnet Prefix (n bits)Subnet Prefix (n bits) 000000 (128000000 (128--n bits)n bits)

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Subnet Prefix (n bits)Subnet Prefix (n bits) 000000 (128000000 (128--n bits)n bits)

P1P1

P2P2

Routing Routing Header Header

including including anycast anycast

address of P1 address of P1 routersrouters

�� They are They are experimental. experimental. They can They can be used, for example, to enable be used, for example, to enable Provider SelectionProvider Selection

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Network Renumbering in IPv6Network Renumbering in IPv6

�� Typical Scenario: Typical Scenario: Change of Provider (ISP)Change of Provider (ISP)

Backbone IPv6Backbone IPv6

Prefix 1Prefix 1

Addresses:Addresses:Prefix1 + EUIPrefix1 + EUI

ISP 1ISP 1

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Prefix 1Prefix 1


ISP 1ISP 1

Prefix 2Prefix 2

Prefix2 + EUIPrefix2 + EUI

ISP 2ISP 2

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Prefix 1Prefix 1


ISP 1ISP 1

Prefix 2Prefix 2

Prefix2 + EUIPrefix2 + EUI

ISP 2ISP 2

Prefix 2Prefix 2

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Renumbering TechniquesRenumbering Techniques

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Renumbering TechniquesRenumbering Techniques�� Hosts:Hosts:

Announcement of new prefixes by routers (using Announcement of new prefixes by routers (using Routing Advertisement messages), orRouting Advertisement messages), orUsing DHCP (DHCPv6 includes an extension disable Using DHCP (DHCPv6 includes an extension disable addresses addresses asignedasigned))

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�� Routers:Routers:RFC 2894: Router Renumbering for IPv6 RFC 2894: Router Renumbering for IPv6 New Protocol to change prefixes exported by routers.New Protocol to change prefixes exported by routers.Uses a new ICMPv6 messageUses a new ICMPv6 message

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�� DNS:DNS:A6 records. Composed of:A6 records. Composed of:

An interface identifierAn interface identifierA reference to a prefixA reference to a prefix

To renumber you only need to change the prefix DNS To renumber you only need to change the prefix DNS record, not the host recordsrecord, not the host records

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�� DNS:DNS:A6 records. Composed of:A6 records. Composed of:

An interface identifierAn interface identifierA reference to a prefixA reference to a prefix

To renumber you only need to change the prefix DNS To renumber you only need to change the prefix DNS record, not the host recordsrecord, not the host records

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MultihomingMultihoming

�� Two types:Two types:Host multihomingHost multihoming

Two or more unicast address on an interfaceTwo or more unicast address on an interfaceTwo or more network interfacesTwo or more network interfaces

Site multihomingSite multihomingMultiple connections to the same ISPMultiple connections to the same ISPConnections to multiple ISPsConnections to multiple ISPs

�� Why Why multihomemultihome??Redundancy against router/link/ISP failureRedundancy against router/link/ISP failureLoad sharingLoad sharingLocal connectivity across large geographyLocal connectivity across large geographyetcetc

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ISP 2ISP 2

Multihoming in IPv4Multihoming in IPv4�� Typically, IPv4 Typically, IPv4 multihomedmultihomed sites:sites:

use provider independent (PI) addressesuse provider independent (PI) addresseshave their own ASN and run BGP with its ISPshave their own ASN and run BGP with its ISPsexport its PI prefix through each ISP peeringexport its PI prefix through each ISP peering

ISP 1ISP 1

MultihomedMultihomed SiteSite

(138.4.1.0/24)(138.4.1.0/24)

ISP 3ISP 3

BGPBGP138.4.1.0/24138.4.1.0/24

BG

PB

GP

138.4.1.0/24

�� Problems:Problems:Routing table explosionRouting table explosionInternet instability (route flaps visible)Internet instability (route flaps visible)

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ISP 2ISP 22001:b00::/242001:b00::/24

Multihoming in IPv6Multihoming in IPv6

�� MultihomedMultihomed sites receive one prefix from each ISPsites receive one prefix from each ISP

�� IPv4IPv4--style style multihomemultihome forbidden:forbidden:IPv6 routing model does not allow the IPv6 routing model does not allow the announcement of prefixes belonging to one ISP announcement of prefixes belonging to one ISP through other ISP’s connectionsthrough other ISP’s connections

ISP 1ISP 1 ISP 3ISP 3

2001:b00:bbbb::/482001:b00:bbbb::/482001:c00:cccc::/482001:c00:cccc::/482001:a00:aaaa::/482001:a00:aaaa::/48

2001:c00::/242001:c00::/242001:a00::/242001:a00::/24

MultihomedMultihomed SiteSite

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�� Not well understood yet. Work in progress by IETFNot well understood yet. Work in progress by IETF

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�� Not well understood yet. Work in progress by IETFNot well understood yet. Work in progress by IETF�� Key functionality for the success of IPv6Key functionality for the success of IPv6

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�� Not well understood yet. Work in progress by IETFNot well understood yet. Work in progress by IETF�� Key functionality for the success of IPv6Key functionality for the success of IPv6�� Several solutions being discussed:Several solutions being discussed:

RouterRouter--basedbasedHostHost--basedbasedMobileMobile--basedbasedGeographic or ExchangeGeographic or Exchange--basedbased

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�� Not well understood yet. Work in progress by IETFNot well understood yet. Work in progress by IETF�� Key functionality for the success of IPv6Key functionality for the success of IPv6�� Several solutions being discussed:Several solutions being discussed:

RouterRouter--basedbasedHostHost--basedbasedMobileMobile--basedbasedGeographic or ExchangeGeographic or Exchange--basedbased

�� See See ipv6mhipv6mh for more information for more information http://arneillhttp://arneill--py.sacramento.ca.us/ipv6mhpy.sacramento.ca.us/ipv6mh

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IPv6 Dynamic Routing Protocols (I)IPv6 Dynamic Routing Protocols (I)

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�� In general, minimal modifications are needed to existing In general, minimal modifications are needed to existing protocols to adapt them to IPv6:protocols to adapt them to IPv6:

mainly related to address formatmainly related to address formatIn some cases, modifications to support IPv4 and IPv6 In some cases, modifications to support IPv4 and IPv6 simultaneously simultaneously (Integrated Routing)(Integrated Routing)

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�� RIPngRIPng (RFC 2080)(RFC 2080)Minimal modifications to RIPv2Minimal modifications to RIPv2

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�� RIPngRIPng (RFC 2080)(RFC 2080)Minimal modifications to RIPv2Minimal modifications to RIPv2

�� OSPFv6 = OSPFv3 for IPv6 (RFC 2740)OSPFv6 = OSPFv3 for IPv6 (RFC 2740)Minimal changes: address format, prefixes, ids., etcMinimal changes: address format, prefixes, ids., etcAuthentication eliminated from OSPF (Authentication eliminated from OSPF (

it uses IPv6 AH/ESP extension headersit uses IPv6 AH/ESP extension headersdraftdraft--ietfietf--ospfospf--ospfv3ospfv3--authauth--01.01.txttxt

It does not use Integrated Routing: It does not use Integrated Routing: “Ships in the “Ships in the night” night”

two copies of OSPF running: one for IPv4 and another two copies of OSPF running: one for IPv4 and another for IPv6for IPv6

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IPv6 Dynamic Routing Protocols (II)IPv6 Dynamic Routing Protocols (II)

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�� InterInter--Domain Routing: BGP4+Domain Routing: BGP4+

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�� InterInter--Domain Routing: BGP4+Domain Routing: BGP4+Used between ISPs and between ISPs and large Used between ISPs and between ISPs and large corporationscorporations

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�� InterInter--Domain Routing: BGP4+Domain Routing: BGP4+Used between ISPs and between ISPs and large Used between ISPs and between ISPs and large corporationscorporationsModifications:Modifications:

RFC 2858 defines RFC 2858 defines multiprotocolmultiprotocol extensions (IPv6, IPX, extensions (IPv6, IPX, etc) to BGPetc) to BGP--4. Compatibility with BGP4. Compatibility with BGP--44

–– Integrating Routing approach Integrating Routing approach RFC 2545 defines how to use extensions for IPv6 RFC 2545 defines how to use extensions for IPv6 (Scopes, Next Hop, etc)(Scopes, Next Hop, etc)

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References (I)References (I)�� Addressing and Routing framework:Addressing and Routing framework:

RFC 1887. An Architecture for IPv6 Unicast Address RFC 1887. An Architecture for IPv6 Unicast Address Allocation Allocation

�� About IPv6 Addressing:About IPv6 Addressing:RFC 3513. Internet Protocol Version 6 (IPv6) Addressing RFC 3513. Internet Protocol Version 6 (IPv6) Addressing ArchitectureArchitectureRFC 2374. An IPv6 RFC 2374. An IPv6 AggregatableAggregatable Global Unicast Address Global Unicast Address Format Format

Being modified by: IPv6 Global Unicast Address Format. Being modified by: IPv6 Global Unicast Address Format. February 2003. Internet Draft, <draftFebruary 2003. Internet Draft, <draft--ietfietf--ipv6ipv6--unicastunicast--aggraggr--v2v2--02.txt>, 02.txt>,

RFC 3531. A Flexible RFC 3531. A Flexible MethodMethod forfor ManagingManaging thethe AssignmentAssignment ofofBits Bits ofof anan IPv6 IPv6 AddressAddress BlockBlock. M. . M. BlanchetBlanchet. . AprilApril 2003 2003 RFC 3041. Privacy Extensions for Stateless Address RFC 3041. Privacy Extensions for Stateless Address Autoconfiguration in IPv6Autoconfiguration in IPv6RFC 3177 IAB/IESG Recommendations on IPv6 Address. IAB, RFC 3177 IAB/IESG Recommendations on IPv6 Address. IAB, IESG. September 2001. IESG. September 2001. RFC 3194 The HRFC 3194 The H--Density Ratio for Address Assignment Density Ratio for Address Assignment Efficiency An Update on the H ratio. A. Durand, C. Efficiency An Update on the H ratio. A. Durand, C. HuitemaHuitema. . November 2001. November 2001.

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References (II)References (II)�� About IPv6 and DNS:About IPv6 and DNS:

RFC 1886 DNS Extensions to support IP version 6. S. RFC 1886 DNS Extensions to support IP version 6. S. Thomson, C. Thomson, C. HuitemaHuitema. December 1995 . December 1995 RFC 2874 DNS Extensions to Support IPv6 Address RFC 2874 DNS Extensions to Support IPv6 Address Aggregation and Renumbering. M. Crawford, C. Aggregation and Renumbering. M. Crawford, C. HuitemaHuitema. . July 2000. July 2000. RFC 3152 Delegation of IP6.ARPA. R. Bush. August 2001. RFC 3152 Delegation of IP6.ARPA. R. Bush. August 2001. 3363 Representing Internet Protocol version 6 (IPv6) 3363 Representing Internet Protocol version 6 (IPv6) Addresses in the Domain Name System (DNS). R. Bush, A. Addresses in the Domain Name System (DNS). R. Bush, A. Durand, B. Fink, O. Durand, B. Fink, O. GudmundssonGudmundsson, T. , T. HainHain. August 2002. . August 2002. RFC 3364. Tradeoffs in Domain Name System (DNS) Support RFC 3364. Tradeoffs in Domain Name System (DNS) Support for Internet Protocol version 6 (IPv6). R. for Internet Protocol version 6 (IPv6). R. AusteinAustein. August . August 2002. 2002.

�� About Routing and autoconfiguration:About Routing and autoconfiguration:RFC 2858. RFC 2858. MultiprotocolMultiprotocol Extensions for BGPExtensions for BGP--4 4 RFC 2545. Use of BGPRFC 2545. Use of BGP--4 4 MultiprotocolMultiprotocol Extensions for IPv6 Extensions for IPv6 InterInter--Domain Routing Domain Routing RFC 2740. OSPF for IPv6 RFC 2740. OSPF for IPv6 RFC 2080. RFC 2080. RIPngRIPng for IPv6 for IPv6 RFC 2894. Router Renumbering for IPv6 RFC 2894. Router Renumbering for IPv6

Documents

UPM, May, 2003studies.ac.upc.edu/doctorat/NGN/GIS2003_TutorialIPv6_2.pdf · Need for renumbering techniques Need for new multihoming techniques Minimal modifications to dynamic routing