ipv6 routing protocols

• Overview• Overview

• Static Routing

• Dynamic Routing

• RIPng

• EIGRP for IPv6

• OSPFv3

© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2

• OSPFv3

• Main motivation for IPv6 is lack of IPv4 address space

• IPv4 uses 32-bits

2^32 = 4,294,967,296 max addresses

• IPv6 uses 128-bits

2^128 = 34,028,236,6 92,938,463,463,374,607,431,770,000,000+


• IPv4 Dotted Decimal

1.2.3.4

Each place denotes 1 byteEach place denotes 1 byte

• IPv6 Hexadecimal

XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX

Two characters = one byte


• 2.4 Address Type Representation

• The specific type of an IPv6 address is indicated by the leading bits in the address. The variable-length field comprising these leading bits is called the Format Prefix (FP). The initial allocation of these prefixes is as follows:these prefixes is as follows:

• Allocation Prefix Fraction of (binary) Address Space

• ----------------------------------- -------- -------------

• Aggregatable Global Unicast Addresses 001 1/8

• Link-Local Unicast Addresses 1111 1110 10 1/1024


• Link-Local Unicast Addresses 1111 1110 10 1/1024

• Site-Local Unicast Addresses 1111 1110 11 1/1024

• Multicast Addresses 1111 1111 1/256

• • Four main address types

• Global Unicast

�2000… – 3FFF…�2000… – 3FFF…

• Unique Local

�FC00…

Deprecates Site Local (FEC0)

• Link Local


• Link Local

�FE80…

• Multicast

�FF…

• IPv6 host addresses are generated from interface MAC address

• MAC address is 48-bits

• IPv6 host address is 64-bits• IPv6 host address is 64-bits

• Extra 16 bits derived as follows:

MAC 1234.5678.9012

Invert 7th most significant bit

12 = 0001 0010

0001 0000


0001 0000

1034.5678.9012

• Insert “FFFE” in middle

1034:56FF:FE78:9012

• ICMPv6 ND

� Replaces IPv4 ARP

• NS – Neighbor Solicitation• NS – Neighbor Solicitation

� Ask for information about neighbor

• NA – Neighbor Advertisement

� Advertise yourself to other neighbors

• RS – Router Solicitation

� Ask for information about local routers


� Ask for information about local routers

• RA – Router Advertisement

� Advertise yourself as an active router

• IPv6 unicast routing off by default

� ipv6 unicast-routing

• Dynamic routing through• Dynamic routing through

� RIPng

� OSPFv3

� EIGRPv6

� IS-IS

� BGP

• • Dynamic information recurses to remote linklocal address


• • Dynamic information recurses to remote linklocal address

Layer 3 to layer 2 resolution on multipoint NBMA medias

• Similar to IPv4

• Next hop / interface is required Static routing CLI for IPv6

ipv6 route ipv6-prefix/prefix-length {ipv6-address | interface-type interface-number [ipv6-address]}

[administrative-distance] [administrative-multicast-distance | unicast | multicast] [tag tag]

!

Router(config)# ipv6 route 2001:DB8::0/32 2001:DB8:1:1::1 10

!

Router(config)# ipv6 route 2001:DB8::/32 Ethernet 1/0 FE80::215:C7FF:FE21:8640

!

Forward a packets via GUA NH using admin of 10

Forward a packets via link-local NH


LAN1: 2001:db8:c18:1::/64

Ethernet0

Router 2

IPv6 Internet

:a

:e

router 1#config termipv6 unicast-routing!interface Ethernet0

LAN2: 2001:db8:c18:2::/64

Ethernet1

Router 1

:a

:a


interface Ethernet0ipv6 address 2001:db8:c18:1::a/64 !interface Ethernet1ipv6 address 2001:db8:c18:2::a/64!ipv6 route ::/0 2001:db8:c18:1::e

Default router to Router 2

• Routing in IPv6 is unchanged from IPv4

Still has two families of routing protocols: IGP and EGP

Still uses the longest-prefix match routing algorithm

• IGP

RIPng (RFC 2080)

Cisco EIGRP for IPv6

Integrated IS-IS for IPv6 (RFC 5308)

OSPFv3 (RFC 5340)

• EGP


MP-BGP4 (RFC 4760) and Using MP-BGP for IPv6 (RFC 2545)

• Cisco IOS supports all IPv6 routing protocols

• Dynamic routing protocols require a router-id

Router-id is a 32 bit integer in dotted decimal notation (a.b.c.d)

Auto-generated from IPv4 loopback interface address if configured,

Otherwise highest IPv4 address on the routerOtherwise highest IPv4 address on the router

Many networks will deploy IPv6 dual stack – so router-id will be automatically created

• For IPv6 only networks where no IPv4 address is available

Router-id needs to be manually configured using dotted decimal notation (looks like an IPv4 address)

ipv6 router ospf 100

router-id 10.1.1.4


• Referred to as RIP Next Generation, distance vector protocol

• For the SP industry not recommended, limited use in Enterprise environments

• ISPs do not use RIP in any form unless there is absolutely no alternative• ISPs do not use RIP in any form unless there is absolutely no alternative

• RIPng was used in the early days of the IPv6 test network

Superior routing protocols such as ISIS, OSPF and BGP rapidly replaced RIPng


• Similar to RIPv2

Distance-vector, Hop limit of 15, split-horizon, All RIP routers is FF02::9, UDP port (521)

• Updated features for IPv6

Prefix length added, address-family and subnet mask fields removed

Field’s Name kept from IPv4 to IPv6

Fields not kept in IPv6

Name and/or position changed in IPv6

New Field in IPv6

Leg

en

d

Command Version Set to zero

Address Family ID Route Tag

Command Version Set to zero

IPv6 Next Hop

0 0 0xFF

Prefix length added, address-family and subnet mask fields removed

• Special Handling for the NH

One NH entry per group of prefixes

RIP header

RIPng header

Routing Table Entry (RTE)for next hop


Address Family ID Route Tag

IPv4 Prefix

Subnet Mask

Next Hop

Metric

0 0 0xFF

IPv6 prefix

Route Tag Prefix Len Metric

Routing Table Entry (RTE)for prefixes (1 .. N) sharing same next hop

Router2#config term

LAN1: 2001:db8:c18:1::/64

Ethernet0

Router 2

2001:db8:c18:1:260:3eff:fe47:1530

::/0

Ethernet0

Default route from R2

Router2#config term

ipv6 router rip RT0

interface Ethernet0

ipv6 address 2001:db8:c18:1::/64 eui-64

ipv6 rip RT0 enable

ipv6 rip RT0 default-information originate

LAN2: 2001:db8:c18:2::/64

Ethernet0

Ethernet1

Router 1

Router2# debug ipv6 rip

Router1#config term

ipv6 router rip RT0

!

interface Ethernet0 Show RIP update

Enable RIP routing


Router2# debug ipv6 rip

RIPng: Sending multicast update on Ethernet0 for RT0

src=FE80::260:3eff:fe47:1530

dst=FF02::9 (Ethernet0)

sport=521, dport=521, length=32

command=2, version=1, mbz=0, #rte=1

tag=0, metric=1, prefix=::/0

interface Ethernet0


ipv6 rip RT0 enable

!

interface Ethernet1


ipv6 rip RT0 enable

Show RIP update

Use link-local as source

Destination is All RIPng routers

R1# show ipv6 routeIPv6 Routing Table - 10 entriesCodes: C - Connected, L - Local, S - Static, R - RIP, B - BGP

U - Per-user Static routeI1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summaryO - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2D - EIGRP, EX - EIGRP external

C 2001:DB8:1::/64 [0/0]via ::, Loopback1

L 2001:DB8:1:0:A8BB:CCFF:FE00:100/128 [0/0]via ::, Loopback1

R 2001:DB8:2::/64 [120/2]via FE80::A8BB:CCFF:FE00:200, Serial2/0


C 2001:DB8:12::/64 [0/0]via ::, Serial2/0

L 2001:DB8:12:0:A8BB:CCFF:FE00:100/128 [0/0]

Note all RIP next hops are link-local addresses (FE80::)


L 2001:DB8:12:0:A8BB:CCFF:FE00:100/128 [0/0]via ::, Serial2/0


L FF00::/8 [0/0]via ::, Null0

• Three new TLVs:

0X0401 - Internal Prefix

0X0402 - External Prefix

0X0403 - Unused0X0403 - Unused

• Hello messages use the link-local address as the src and dst of FF02::A (all EIGRProuters).

Neighbors do not have to share the same global prefix (with the exception of explicitly specified neighbors)

• Automatic summarization is disabled by default for IPv6 (unlike IPv4)

• Support for “no split-horizon” in the case of NBMA links


• Support for “no split-horizon” in the case of NBMA links

For example, multi-point GRE as found in DMVPN deployments, or ATM/Frame services

• RID stays at 32 bits

• Expected to be very popular amongst existing enterprise networks

Router2#config termipv6 router eigrp 100eigrp router-id 10.10.10.1

LAN1: 2001:db8:c18:1::/64

Ethernet0

Router 2 2001:db8:c18:1:260:3eff:fe47:1530

Ethernet0

interface Ethernet0ipv6 address 2001:db8:c18:1::/64 eui-64ipv6 eigrp 100

LAN2: 2001:db8:c18:2::/64

Ethernet1

Router 1

Router1# show ipv6 eigrp neighborIPv6-EIGRP neighbors for process 100H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num Neighbors and next hops are identified by link-local address


(ms) Cnt Num0 FE80::260:3eff:fe47:1530 E0 14 00:01:43 1 4500 0 1

Router1# show ipv6 eigrp topology all-linksIPv6-EIGRP Topology Table for AS(100)/ID(10.10.10.1)Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,

r - reply Status, s - sia StatusP 2001:db8:c18:1::/64, 1 successors, FD is 28160, serno 1

via Connected, Ethernet0via FE80::260:3eff:fe47:1530 (30720/28160), Ethernet0

• OSPFv3 is OSPF for IPv6 (RFC 5340)

• Based on OSPFv2 with enhancements

• Distributes IPv6 prefixes only• Distributes IPv6 prefixes only

• Runs directly over IPv6

• Ships-in-the-night with OSPFv2


• OSPFv3 has same 5 packet types some fields have been changed

• OSPFv3 packets have a 16 byte header verses the 24 byte header in OSPFv2

Packet Type Description

1 Hello1 Hello

2 Database description

3 Link state request

4 Link state update

5 Link state acknowledgement

Version Type Packet Length

Router ID

Field’s Name kept from IPv4 to IPv6

Fields not kept in IPv6

Name and/or position changed in IPv6

New Field in IPv6

Leg

en

d

Version Type Packet Length

Router ID

OSPFv3OSPFv2


Router ID

Area ID

Checksum Authtype

Authentication

Authentication

Router ID

Area ID

ChecksumInstance

ID0

• Uses link local addresses

To identify the OSPFv3 adjacency neighbors

• Two New LSA Types

Link-LSA (LSA Type 0x0008)

There is one Link-LSA per link. This LSA advertises the router's link-local address, list of all IPv6 prefixes and options associated with the link to all other routers attached to the link

Intra-Area-Prefix-LSA (LSA Type 0x2009)

Carries all IPv6 prefix information that in IPv4 is included in Router-LSAs and Network-LSAs

• Two LSAs are renamed


• Two LSAs are renamed

Type-3 summary-LSAs, renamed to “Inter-Area-Prefix-LSAs”

Type-4 summary LSAs, renamed to “Inter-Area-Router-LSAs”

• Multicast Addresses

FF02::5 – Represents all SPF routers on the link local scope, Equivalent to 224.0.0.5 in OSPFv2

FF02::6 – Represents all DR routers on the link local scope, Equivalent to 224.0.0.6 in OSPFv2

• Removal of Address Semantics

IPv6 addresses are no longer present in OSPF packet header (Part of payload information)

Router LSA, Network LSA do not carry IPv6 addresses

Router ID, Area ID and Link State ID remains at 32 bits

DR and BDR are now identified by their Router ID and no longer by their IP address

• Security


OSPFv3 uses IPv6 AH & ESP extension headers instead of variety of mechanisms defined in OSPFv2

LSA Description LSA Code LSA Type Bits Set=1

Router LSA 1 0x2001 S1

Network LSA 2 0x2002 S1

Inter-Area-Prefix-LSA 3 0x2003 S1

U Bit LSA Handling

0 Treat the LSA as if it had link-local flooding scope

1 Store and flood the LSA as if the type is understood

Inter-Area-Prefix-LSA 3 0x2003 S1

Inter-Area-Router-LSA 4 0x2004 S1

AS-External-LSA 5 0x4005 S2

Deprecated 6 0x2006 S1

NSSA-LSA 7 0x2007 S1

Link-LSA 8 0x0008

Intra-Area-Prefix-LSA 9 0x2009 S1

S2 S1 Flooding Scope

0 0 Link-Local Scoping - Flooded only on originating link

0 1 Area Scoping - Flooded only in originating area

1 0 AS Scoping - Flooded throughout AS

1 1 Reserved


Intra-Area-Prefix-LSA 9 0x2009 S1

U S2 S1 LSA Function Code

1Bit 1Bit 1Bit 13 Bits

LSA Type Format

Router1#interface POS1/1ipv6 address 2001:410:FFFF:1::1/64ipv6 ospf 100 area 0! interface POS2/0ipv6 address 2001:db8:FFFF:1::2/64Router 2

Area 1Enables IPv6 facing Area 0

Interlink connection (could use link-local)

POS3/0 2001:db8:ffff:1::1/64

POS1/1

Router 1

ipv6 address 2001:db8:FFFF:1::2/64ipv6 ospf 100 area 0! ipv6 router ospf 100

router-id 10.1.1.3

Router2#interface POS3/0ipv6 address 2001:db8:FFFF:1::1/64ipv6 ospf 100 area 0! ipv6 router ospf 100

router-id 10.1.1.4

Router 2

POS 2/0 2001:db8:ffff:1::2/64

Area 032 bit ID specified in dotted decimal notation




2001:410:ffff:1::1/64

router-id 10.1.1.4Area 032 bit ID specified in dotted decimal notation

Router1#interface POS1/1ipv6 address 2001:410:FFFF:1::1/64ospfv3 100 area 0 ipv6! interface POS2/0ipv6 address 2001:db8:FFFF:1::2/64Router 2

Area 1Enables IPv6 facing Area 0


POS3/0 2001:db8:ffff:1::1/64

POS1/1

Router 1

ipv6 address 2001:db8:FFFF:1::2/64ospfv3 100 area 1 ipv6! router ospfv3 100

router-id 10.1.1.3

Router2#interface POS3/0ipv6 address 2001:db8:FFFF:1::1/64ospfv3 100 area 1 ipv6! router ospfv3 100

router-id 10.1.1.4

Router 2

POS 2/0 2001:db8:ffff:1::2/64

Area 032 bit ID specified in dotted decimal notation




2001:410:ffff:1::1/64

router-id 10.1.1.4Area 032 bit ID specified in dotted decimal notation

Supported as of 15T/15S IOS trains

ipv6 routing protocols

Documents

dotted decimal

routing table

link local

position changed

interlink

64 eui

leading bits

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