IPv6 Routing

1

• IPv6 Routing
• Dave Wilson
• DW238-RIPE

2

• Routing
• internal and external

3

• ipv6 unicast-routing

4
Routing protocols

• Statics gt no change
• OSPF gt OSPFv3
• ISIS gt ISIS
• BGP gt BGP4 (or MBGP)

5
Static routes

• ipv6 route 200177010/48 2001770832 100
• ipv6 route 2002/16 Tunnel64
• 0.0.0.0/0 is now known as /0
• For finer RPF granularity, use 2000/3

6
OSPFv3

• Uses a different OSPF processthan the one for
  IPv4
• "network" command not used,enable OSPF in the
  interface config
• IPv6-only routers need a 32 bitrouter-id
  specifically set

7
Configuring OSPFv3

• !
• ipv6 ospf 100 area 1
• router-id 1.2.3.4
• !
• interface FastEthernet0/0
• ipv6 address 2001db81001001/64
• ipv6 enable
• ipv6 ospf 100 area 1
• !

8
IS-IS

• Uses same IS-IS process,with IPv6 address-family
• Trouble running IS-IS over 6in4 tunnels
• Need a unique NET address

9
Configuring IS-IS

• !
• router isis backbone
• !
• address-family ipv6
• redistribute static
• exit-address-family
• net 49.0001.0770.0008.0000.00
• !

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Configuring IS-IS

• !
• interface FastEthernet0/0.2
• encapsulation dot1Q 2
• ipv6 address 2001770182/64 eui-64
• ipv6 router isis backbone
• !
• Configure this on the loopback interface as well

11
Monitoring the IGP

• salingersh ipv6 route 2001770810
• IPv6 Routing Table - 559 entries
• Codes 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 2
• I1 2001770810/64 115/20
• via FE8020A8BFFFE0B3935,
  FastEthernet0/0.99

12
BGP4

• BGP for customer-to-ISP connection has distinct
  advantages
• Much better routing security
• Finer grained control for load sharing/backup
  links
• Reduces the size of OSPF/ISIS table
• Scales better when OSPF/ISIS is small

13
BGP4

• Same process as used for IPv4
• Different IPv4 and IPv6 sessions to the same
  router
• AS-path filter lists may be shared
• Same best path selection algorithm applies
• Can implement identical or separate routing
  policies

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BGP4

• Every network has an Autonomous System number
• HEAnet LIR will give you a private one if you
  dont have your own
• BGP runs as a TCP application between our routers
• Sends and receives the routes you want, with
  strong filtering on both sides

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Peer Groups

• Optional first step a peer group
• router bgp 1213
• neighbor heanet-v6 peer-group
• neighbor heanet-v6 remote-as 65001
• Sets up a template which can be applied to real
  peers

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Address families

• Anything which affects establishing the BGP
  session goes in the global BGP config
• Anything that affects the routes you send or
  receive goes in an address-family

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Address families

• address-family ipv6
• network 2001db8100/48
• Network what we advertise as local- but only
  if we have a route to them
• neighbor heanet-v6 activate
• neighbor heanet-v6 maximum-prefix 20
• Limit the number of routesthis session may
  receive

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Address families

• neighbor heanet-v6 route-map pri-out-v6 out
• neighbor heanet-v6 filter-list 10 out
• neighbor heanet-v6 send-community both
• Affects the routes we send to remote peer
• route-map pri-out-v6 permit 40
• match ipv6 address prefix-list cust-routes-v6
• ipv6 prefix-list cust-routes-v6 seq 10 \
• permit 2001db8100/48

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Address families

• neighbor heanet-v6 prefix-list default-v6 in
• Affects routes we accept from the remote peer
• ipv6 prefix-list default-v6 seq 10 permit /0

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Address families

• Route wont be sent unless it also appears in our
  local routing table
• ipv6 route 2001db8100/48 null0 254
• Nail it up with a high cost
• Any more specific routes will take precedence
  when routing traffic
• so /64s always win

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Establishing a session

• Now the groundwork has been prepared we may bring
  up the BGP session
• router bgp 1213
• neighbor 2001db811 peer-group heanet-v6
• neighbor 2001db811 description Uplink
• !
• address-family ipv6
• neighbor 2001db811 activate
• neighbor 2001db811 peer-group heanet-v6
• exit-address-family

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BGP What's changed

• Protocol-specific stuff has moved
• Activate or deactivate peers in address-families
  (to avoid next-hop madness)
• Other networks have varying policies on what
  routes they accept
• WHOIS only just caught up

23
BGP What's the same

• A link is a link - native or tunnelled
• route-maps, filter lists, localpref, path
  stuffing, communities as with ipv4
• Still need an iBGP full mesh, or route
  reflectors/confederations
• next-hop is still an IP address, must be
  reachable through your IGP

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BGP What's the same

• Still need next-hop-self on iBGP sessions
• You still need to nail up the aggregate route
• router bgp 1213
• address-family ipv6
• network 2001db8100/48
• exit-address-family
• ipv6 route 2001db8100/48 null0

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Monitoring BGP

• Deimosshow bgp ipv6 summary
• BGP router identifier 193.1.195.69, local AS
  number 1213
• Neighbor V AS MsgRcvd MsgSent TblVer
  InQ OutQ Up/Down State/PfxRcd
• 20017708 4 1213 43554 29161 59095
  0 0 5d00h 305
• 2001770810 4 1213 7433 29149 59095
  0 0 5d03h 1
• 2001770888 4 1213 62765 29319 59095
  0 0 5d02h 312
• 2001770906 4 1213 7445 29224 59095
  0 0 5d03h 4
• 20017704003
• 4 1213 21549 29141 59095
  0 0 5d03h 1
• 2001770800 4 1213 14844 36616 59095
  0 0 5d03h 1
• 20017701000 4 1213 7433 29229 59095
  0 0 5d03h 1
• 20017701800 4 1213 7432 29205 59095
  0 0 5d03h 1
• 2001798201910AA1
• Neighbor V AS MsgRcvd MsgSent TblVer
  InQ OutQ Up/Down State/PfxRcd
• 4 20965 18726 14866 59093
  0 0 5d03h 272
• Deimos

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Monitoring BGP

• Deimossh bgp ipv6 n 2001798201910AA1 route
• BGP table version is 59110, local router ID is
  193.1.195.69
• Status codes s suppressed, d damped, h history,
  valid, gt best, i - internal,
• S Stale
• Origin codes i - IGP, e - EGP, ? - incomplete
• Network Next Hop Metric
  LocPrf Weight Path
• 2001200/35 2001798201910AA1
• 
  0 20965 11537 2500 i
• 2001200/32 2001798201910AA1
• 
  0 20965 11537 2500 i
• 2001208/32 2001798201910AA1
• 
  0 20965 11537 7610 i
• 2001218/32 2001798201910AA1
• 
  0 20965 11537 145 2914 i
• gt 2001220/35 2001798201910AA1
• 
  0 20965 1299 1752 9270 i

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Monitoring BGP

• Must specify exact prefix
• Deimosshow bgp ipv6 2001200/35
• BGP routing table entry for 2001200/35,
  version 15749
• Paths (2 available, best 1, table
  Global-IPv6-Table)
• Not advertised to any peer
• 3425 2500
• 2001770888 (metric 20) from
  2001770888 (193.1.195.41)
• Origin IGP, metric 0, localpref 100, valid,
  internal, best
• 20965 11537 2500, (aggregated by 2500
  192.50.36.15)
• 2001798201910AA1 from 2001798201910AA
  1 (62.40.102.45)
• Origin IGP, localpref 100, valid, external,
  atomic-aggregate
• Community 115372501 2096511537
• Deimos

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Monitoring BGP

• Must specify exact prefix
• Deimosshow bgp ipv6 2001200/35
• BGP routing table entry for 2001200/35,
  version 15749
• Paths (2 available, best 1, table
  Global-IPv6-Table)
• Not advertised to any peer
• 3425 2500
• 2001770888 (metric 20) from
  2001770888 (193.1.195.41)
• Origin IGP, metric 0, localpref 100, valid,
  internal, best
• 20965 11537 2500, (aggregated by 2500
  192.50.36.15)
• 2001798201910AA1 from 2001798201910AA
  1 (62.40.102.45)
• Origin IGP, localpref 100, valid, external,
  atomic-aggregate
• Community 115372501 2096511537
• Deimos

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Agenda

• Basic differences between v4 and v6
• Layer 2 types of connectivity
• Layer 3 how to route
• Gotchas

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• Gotchas

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• Different routing protocols
• Different layouts
• Different routes

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• Performance
• Hardware gt Software gt Tunnels

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• Application failover
• Application ignorance

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• Autoconfiguration
• and
• automatic chaos

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Lab

• Enter enable mode, enaIPv4 connectivity is
  already set up
• Configure IPv6 on your physical interface
• Configure a BGP peer-group
• Bring up a BGP session