IPv6 Routing IPv6 Workshop Manchester September 2013 Kateel Vijayananda [email protected] Wim Verrydt [email protected].

IPv6 Routing

IPv6 Workshop ManchesterSeptember 2013

Kateel Vijayananda

[email protected]

Wim Verrydt

[email protected]

AgendaOverviewOSPFv3IS-ISMP-BGP

Each IPv4 Routing Protocol has an IPv6 Equivalent

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RIPv2 RIPng

OSPFv2 OSPFv3

IS-IS IS-IS for IPv6

EIGRP EIGRP for IPv6

BGP MP-BGP

AgendaOverviewOSPFv3IS-ISMP-BGP

OSPFv3 vs OSPFv2 – Similarities are…

Defined in RFC 5340 – OSPF for IPv6

Runs directly over IPv6 (Extension Header 89)

Neighbor discovery and adjacency formation

mechanisms are identical

• All OSPF Routers FF02::5, All OSPF DRs FF02::6

LSA flooding and aging mechanisms are identical

Same interface types

• P2P, P2MP, Broadcast, NBMA, Virtual

Independent process from OSPFv2

OSPFv3 vs OSPFv2 – Differences are…Removal of Addressing Semantics

Per Link Processing

Instance ID

LS Type in LSA Header is 16 bits in IPv6 (8 bits in IPv4)

Explicit Flooding Scopes

Explicit Unknown LSA Handling

Adjacency formed over the Link-local address

Authentication changes

OSPFv3 vs OSPFv2 – Differences are…

• New Link-LSA

‒ LSA 8

‒ Announces IPv6 LLA to routers on the link

‒ Announces IPv6 prefixes associated with the link

‒ Generated for every link with 2 or more routers

• New Intra-Area-Prefix LSA

‒ LSA 9

‒ Associates list of IPv6 Prefixes with network or router

OSPFv3 – Flooding Scope

Each LSA now contains two bits indicating the flooding scope• AS scope, LSA is flooded throughout the AS

• Area scope, LSA is flooded only within an area

• Link-local scope, LSA is flooded only on the local link

Indicated by “S bit” is LSA Link State Type Field

S2 S1 Flooding Scope

0 0 Link-Local

0 1 Area

1 0 AS (Routing Domain)

1 1 Reserved

OSPFv3 – Flooding Scope – Cntd.

These changes also impact the names of the LSAs• Type 3 (Summary LSA) = the Inter-area-

prefix-LSA

• Type 4 (Autonomous System Border LSA) = the Inter-area-router-LSA

• Other new LSAs have been added (Link-LSA, Intra-area-prefix-LSA)

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OSPFv3 LSA Types

LS Type Name

0x2001 Router LSA

0x2002 Network LSA

0x2003 Inter-Area Prefix LSA

0x2004 Inter-Area Router LSA

0x4005 AS-External LSA

0x2006 Group Membership LSA

0x2007 Type-7 LSA

0x0008 Link LSA

0x2009 Intra-Area Prefix LSA

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OSPFv3 process 2 on a LAN router with a Router-ID• Includes loopback, LAN and backbone interface

Configuring OSPFv3

!ipv6 unicast-routing!ipv6 router ospfv3 2 router-id 10.<x>.0.1!interface Loopback0 ipv6 address 2001:DB8:<x>:<x>::1/128 ipv6 ospf 2 area <x>!interface Vlan <100+x> ipv6 address 2001:DB8:<x>:CAFE::/64 eui-64 ipv6 ospf 2 area <x>!interface <backbone interface> ipv6 address 2001:DB8:<x>:102::<x>/127 ipv6 ospf 2 area <x>!

!ipv6 unicast-routing!ipv6 router ospfv3 2 router-id 10.<x>.0.1!interface Loopback0 ipv6 address 2001:DB8:<x>:<x>::1/128 ipv6 ospf 2 area <x>!interface Vlan <100+x> ipv6 address 2001:DB8:<x>:CAFE::/64 eui-64 ipv6 ospf 2 area <x>!interface <backbone interface> ipv6 address 2001:DB8:<x>:102::<x>/127 ipv6 ospf 2 area <x>!

OSPFv3 – Show Example

POS 3/02001:b00:ffff:1::1/64

2001:b00:ffff:1::2/64POS 2/0

Area 1

Area 0

POS 1/12001:410:ffff:1::1/64

Router 2

Router 1

Router2#sh ipv6 routeIPv6 Routing Table - 5 entriesCodes: C - Connected, L - Local, S - Static, R - RIP, B – BGP, U - Per-user Static route I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2OI 2001:410:FFFF:1::/64 [110/2] via FE80::2D0:FFFF:FE60:DFFF, POS3/0C 2001:B00:FFFF:1::/64 [0/0] via ::, POS3/0L 2001:B00:FFFF:1::1/128 [0/0] via ::, POS3/0L FE80::/10 [0/0] via ::, Null0L FF00::/8 [0/0] via ::, Null0

Router2#sh ipv6 routeIPv6 Routing Table - 5 entriesCodes: C - Connected, L - Local, S - Static, R - RIP, B – BGP, U - Per-user Static route I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2OI 2001:410:FFFF:1::/64 [110/2] via FE80::2D0:FFFF:FE60:DFFF, POS3/0C 2001:B00:FFFF:1::/64 [0/0] via ::, POS3/0L 2001:B00:FFFF:1::1/128 [0/0] via ::, POS3/0L FE80::/10 [0/0] via ::, Null0L FF00::/8 [0/0] via ::, Null0

AgendaOverviewOSPFv3IS-ISMP-BGP

IS-IS/IPv6 – Protocol Changes

RFC 5308 – Routing IPv6 with IS-IS

Originally routing only CLNP, then IPv4, now IPv6

Operationally similar to IS-ISv4

A new Network Layer Protocol Identifier (NLPID) is

defined• Advertise IPv6 prefix payload using 0x8E value

New address family added

Neighbors listed in the Adjacency table with their LLA

Same protocol iteration can route both IPv4 and IPv6

IS-IS/IPv6 – New TLVs

Two type/length/values added to introduce IPv6 routing

IPv6 reachability TLV (0xEC)• IPv6 routing prefix, metric information and some option bits. • Equivalent to IP Internal/external reachability TLVs (RFC 1195)

IPv6 interface address TLV (0xE8)• Contains 128-bit address• Hello PDUs contain the link-local address (FE80::/10)• LSP only contain the non-link-local address

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IS-IS/IPv6 – Single versus Multi-Topology

Single Topology• The IPv4 and IPv6 topologies must match• One SPF is run; IPv4 and IPv6 are mixed on

the resulting SPT• Usually deployed

Multi-topology• Uses a different address family for IPv6

destinations• IPv4 and IPv6 topologies do not need to

match• Useful for deployment where Dual Stack can

not enabled everywhere• Multi-Topology_Reachable_IPv6_Prefixes TLV

IS-IS for IPv6 – Configure Single- and Multi-Topology

Implementing IS-IS for IPv6http://www.cisco.com/en/US/docs/ios-xml/ios/ipv6/

configuration/15-2mt/ip6-is-is.html

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!ipv6 unicast-routing !router isis net 49.0001.0000.0000.000c.00 !interface GigabitEthernet0/0/1 ipv6 address 2001:DB8::3/64 ipv6 router isis!

!ipv6 unicast-routing!router isis metric-style wide net 49.0001.0000.0000.000c.00 address-family ipv6 multi-topology exit-address-family!interface GigabitEthernet0/0/1 ipv6 router isis isis ipv6 metric 20!

AgendaOverviewOSPFv3IS-ISMP-BGP

MP-BGP Basics

Path Vector Protocol• Carries sequence of AS numbers indicating path

Ties Autonomous Systems together via Peering (EGP)Multiple address families: IPv4, IPv6, unicast, multicast, VPNv4, VPNv6Multi-Protocol Extension for IPv6 in RFC 2545

AS 101AS 201

AS 301

Peering

MP-BGP-4 Extensions

BGP-4 carries only 3 pieces of information which are truly IPv4 specific:• NLRI in the UPDATE message contains an IPv4 prefix• NEXT_HOP path attribute in the UPDATE message contains a

IPv4 address• BGP Identifier in the OPEN message & AGGREGATOR

attribute

Multi-Protocol Extensions in RFC 4760 (2238, 2858)• Enables BGP-4 to carry information of other protocols e.g

MPLS, IPv6• Protocol independent NEXT_HOP attribute• Protocol independent NLRI attribute• New BGP-4 optional and non-transitive attributes:• MP_REACH_NLRI• MP_UNREACH_NLRI• To associate NLP with NH and NLRI => AFI + SAFI

MP-BGP-4 Extensions for IPv6

Address Family Information (AFI) for IPv6• AFI = 2 • Sub-AFI = 1 Unicast• Sub-AFI = 2 (Multicast for RPF check)• Sub-AFI = 3 for both Unicast and Multicast• Sub-AFI = 4 Label• Sub-AFI = 128 VPN

TCP Interaction• BGP-4 runs on top of TCP• This connection could be setup either over IPv4 or IPv6

Router ID• When no IPv4 is configured, an explicit BGP router-id needs

to be configured• Needed as a BGP Identifier, used as a tie breaker, and is

send within the OPEN message

MP-BGP – Configure IPv6

Implementing Multiprotocol BGP for IPv6• http://www.cisco.com/en/US/docs/ios-xml/ios/ipv6/configuration/15-

2mt/ip6-mptcl-bgp.html

!ipv6 unicast-routing !router bgp 65000 no bgp default ipv4-unicast bgp router-id 192.168.99.70 neighbor 2001:DB8:0:CC00::1 remote-as 64600 address-family ipv6 unicast neighbor 2001:DB8:0:CC00::1 activate network 2001:DB8::/32 exit-address-family!