Anycast | SysNetBR

Introdução

Neste laboratório, vamos simular uma rede para compreender na prática como funciona o roteamento Anycast com IPv6. O ambiente contará com cinco roteadores principais, cada um pertencente a um sistema autônomo (ASN) distinto, representando diferentes provedores (ISPs). Atuaremos como o ASN 64320, que hospedará o roteador e o servidor que responderá por um endereço IPv6 anycast.

O roteador do ASN 64320 será conectado a um switch dentro de cada um dos quatro ASNs simulados. Em cada caso, receberemos um endereço IPv6 do respectivo provedor para estabelecer uma sessão BGP com aquele ASN. A partir dessas conexões, anunciaremos o prefixo do nosso ASN e cada ISP será responsável por redistribuí-lo, permitindo que o endereço anycast seja acessado de diferentes pontos da rede.

A seguir, apresentamos a tabela com os prefixos e blocos utilizados por cada roteador no cenário:

Roteador	ASN	Prefixo Base	Subrede Loopback	Loopback IP	Rede LAN	Router Network Interface
Router1	65001	2001:db8:1::/48	2001:db8:1:1::/64	2001:db8:1:1::1/128	2001:db8:1:10::/64	2001:db8:1:17::/64
Router2	65002	2001:db8:2::/48	2001:db8:2:1::/64	2001:db8:2:1::2/128	2001:db8:2:10::/64	2001:db8:2:17::/64
Router3	65003	2001:db8:3::/48	2001:db8:3:1::/64	2001:db8:3:1::3/128	2001:db8:3:10::/64	2001:db8:3:17::/64
Router4	65004	2001:db8:4::/48	2001:db8:4:1::/64	2001:db8:4:1::4/128	2001:db8:4:10::/64	2001:db8:4:17::/64
Router5	65005	2001:db8:5::/48	2001:db8:5:1::/64	2001:db8:5:1::5/128	2001:db8:5:10::/64	2001:db8:5:17::/64
Router anycast	64320	2001:db8:ffff::/64	2001:db8:ffff::/64	2001:db8:ffff::9/128	—	—
Servidor anycast	(n/a)	(usa do roteador acima)	—	2001:db8:ffff::100/128	—	—

Abaixo, deixo as conexões ponto a ponto entre os roteadores, especificando as interfaces utilizadas, os endereços IP configurados e os roteadores vizinhos. Essa tabela é essencial para visualizar a topologia e verificar as sessões BGP.

Roteador	Interface	IP Local	Conectado a	IP Remoto
router1_65001	Gig0/0	2001:db8:1:18::1/64	router5_65005	2001:db8:1:18::5/64
router1_65001	Gig0/1	2001:db8:1:17::1/64	router2_65002	2001:db8:1:17::2/64

Roteador	Interface	IP Local	Conectado a	IP Remoto
router2_65002	Gig0/0	2001:db8:2:17::2/64	router3_65003	2001:db8:2:17::3/64
router2_65002	Gig0/1	2001:db8:1:17::2/64	router1_65001	2001:db8:1:17::1/64

Roteador	Interface	IP Local	Conectado a	IP Remoto
router3_65003	Gig0/0	2001:db8:3:17::3/64	router4_65004	2001:db8:3:17::4/64
router3_65003	Gig0/1	2001:db8:2:17::3/64	router2_65002	2001:db8:2:17::2/64

Roteador	Interface	IP Local	Conectado a	IP Remoto
router4_65004	Gig0/0	2001:db8:4:17::4/64	router5_65005	2001:db8:4:17::5/64
router4_65004	Gig0/1	2001:db8:3:17::4/64	router3_65003	2001:db8:3:17::3/64

Roteador	Interface	IP Local	Conectado a	IP Remoto
router5_65005	Gig0/0	2001:db8:1:18::5/64	router1_65001	2001:db8:1:18::1/64
router5_65005	Gig0/1	2001:db8:4:17::5/64	router4_65004	2001:db8:4:17::4/64

ipv4_mapeado

A imagem acima ilustra a topologia da rede utilizada neste exemplo..

Switches

Vamos começar configurando os switches de cada ISP, todos possuem as mesmas portas em uso, para simplificar, a porta G0/0 que terá um Roteador conectado, vou deixar a descrição apenas como router, assim podemos reutilizar a mesma configuração (isso vale para o nome do switch).

# Para a maioria dos Switches:
enable 
conf t
!
hostname switch
!
interface GigabitEthernet0/0
 description router
 switchport mode access
 no shut
!
interface GigabitEthernet0/1
 description router anycast
 switchport mode access
 no shut
!
interface GigabitEthernet0/2
 description client
 switchport mode access
 no shut
!
end
!
wr




# Para ao Switch do Router3:
enable 
conf t
!
hostname switch
!
interface GigabitEthernet0/0
 description router
 switchport mode access
 no shut
!
interface GigabitEthernet0/2
 description client
 switchport mode access
 no shut
!
end
!
wr

Router 1

Vamos configurar o router1.

enable 
conf t
!
hostname router1_65001
!
ipv6 unicast-routing
!
! Vamos anunciar o /48 que nao esta em nenhuma interface:
ipv6 route 2001:db8:1::/48 Null0
!
interface Loopback0
 ipv6 address 2001:db8:1:1::1/128

interface GigabitEthernet0/0
 description BGP com router5_65005
 ipv6 address 2001:db8:1:18::1/64
 ipv6 enable
 no shut

interface GigabitEthernet0/1
 description BGP com router2_65002
 ipv6 address 2001:db8:1:17::1/64
 ipv6 enable
 no shut

interface GigabitEthernet0/2
 description LAN
 ipv6 address 2001:db8:1:10::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:1:10::/64 1800 1800
 ipv6 nd prefix default
 no shut

router bgp 65001
 bgp router-id 1.1.1.1
 no bgp default ipv4-unicast
 neighbor 2001:db8:1:17::2 remote-as 65002
 neighbor 2001:db8:1:18::5 remote-as 65005
 neighbor 2001:db8:1:10::100 remote-as 64320
 !
 address-family ipv6
  network 2001:db8:1::/48
  neighbor 2001:db8:1:17::2 activate
  neighbor 2001:db8:1:18::5 activate
  neighbor 2001:db8:1:10::100 activate
 exit-address-family
!
end
wr

Router 2

Vamos configurar o router2.

enable 
conf t
!
hostname router2_65002
!
ipv6 unicast-routing
!
! Vamos anunciar o /48 que nao esta em nenhuma interface:
ipv6 route 2001:db8:2::/48 Null0
!
interface Loopback0
 ipv6 address 2001:db8:2:1::2/128

interface GigabitEthernet0/0
 description BGP com router3_65003
 ipv6 address 2001:db8:2:17::2/64
 ipv6 enable
 no shut

interface GigabitEthernet0/1
 description BGP com router1_65001
 ipv6 address 2001:db8:1:17::2/64
 ipv6 enable
 no shut

interface GigabitEthernet0/2
 description LAN
 ipv6 address 2001:db8:2:10::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:2:10::/64 1800 1800
 ipv6 nd prefix default
 no shut

router bgp 65002
 bgp router-id 1.1.1.2
 no bgp default ipv4-unicast
 neighbor 2001:db8:1:17::1 remote-as 65001
 neighbor 2001:db8:2:17::3 remote-as 65003
 neighbor 2001:db8:2:10::100 remote-as 64320
 !
 address-family ipv6
  network 2001:db8:2::/48
  neighbor 2001:db8:1:17::1 activate
  neighbor 2001:db8:2:17::3 activate
  neighbor 2001:db8:2:10::100 activate
 exit-address-family
!
end
wr

Router 3

Vamos configurar o router3.

enable 
conf t
!
hostname router3_65003
!
ipv6 unicast-routing
!
! Vamos anunciar o /48 que nao esta em nenhuma interface:
ipv6 route 2001:db8:3::/48 Null0
!
interface Loopback0
 ipv6 address 2001:db8:3:1::3/128

interface GigabitEthernet0/0
 description BGP com router4_65004
 ipv6 address 2001:db8:3:17::3/64
 ipv6 enable
 no shut

interface GigabitEthernet0/1
 description BGP com router2_65002
 ipv6 address 2001:db8:2:17::3/64
 ipv6 enable
 no shut

interface GigabitEthernet0/2
 description LAN
 ipv6 address 2001:db8:3:10::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:3:10::/64 1800 1800
 ipv6 nd prefix default
 no shut

router bgp 65003
 bgp router-id 1.1.1.3
 no bgp default ipv4-unicast
 neighbor 2001:db8:2:17::2 remote-as 65002
 neighbor 2001:db8:3:17::4 remote-as 65004
 neighbor 2001:db8:3:10::100 remote-as 64320
 !
 address-family ipv6
  network 2001:db8:3::/48
  neighbor 2001:db8:2:17::2 activate
  neighbor 2001:db8:3:17::4 activate
  neighbor 2001:db8:3:10::100 activate
 exit-address-family
!
end
wr

Router 4

Vamos configurar o router4.

enable 
conf t
!
hostname router4_65004
!
ipv6 unicast-routing
!
! Vamos anunciar o /48 que nao esta em nenhuma interface:
ipv6 route 2001:db8:4::/48 Null0
!
interface Loopback0
 ipv6 address 2001:db8:4:1::4/128

interface GigabitEthernet0/0
 description BGP com router5_65005
 ipv6 address 2001:db8:4:17::4/64
 ipv6 enable
 no shut

interface GigabitEthernet0/1
 description BGP com router3_65003
 ipv6 address 2001:db8:3:17::4/64
 ipv6 enable
 no shut

interface GigabitEthernet0/2
 description LAN
 ipv6 address 2001:db8:4:10::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:4:10::/64 1800 1800
 ipv6 nd prefix default
 no shut

router bgp 65004
 bgp router-id 1.1.1.4
 no bgp default ipv4-unicast
 neighbor 2001:db8:3:17::3 remote-as 65003
 neighbor 2001:db8:4:17::5 remote-as 65005
 neighbor 2001:db8:4:10::100 remote-as 64320
 !
 address-family ipv6
  network 2001:db8:4::/48
  neighbor 2001:db8:3:17::3 activate
  neighbor 2001:db8:4:17::5 activate
  neighbor 2001:db8:4:10::100 activate
 exit-address-family
!
end
wr

Router 5

Vamos configurar o router5.

enable 
conf t
!
hostname router5_65005
!
ipv6 unicast-routing
!
! Vamos anunciar o /48 que nao esta em nenhuma interface:
ipv6 route 2001:db8:5::/48 Null0
!
interface Loopback0
 ipv6 address 2001:db8:5:1::5/128

interface GigabitEthernet0/0
 description BGP com router1_65001
 ipv6 address 2001:db8:1:18::5/64
 ipv6 enable
 no shut

interface GigabitEthernet0/1
 description BGP com router4_65004
 ipv6 address 2001:db8:4:17::5/64
 ipv6 enable
 no shut

interface GigabitEthernet0/2
 description LAN
 ipv6 address 2001:db8:5:10::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:5:10::/64 1800 1800
 ipv6 nd prefix default
 no shut

router bgp 65005
 bgp router-id 1.1.1.5
 no bgp default ipv4-unicast
 neighbor 2001:db8:1:18::1 remote-as 65001
 neighbor 2001:db8:4:17::4 remote-as 65004
 neighbor 2001:db8:5:10::100 remote-as 64320
 !
 address-family ipv6
  network 2001:db8:5::/48
  neighbor 2001:db8:1:18::1 activate
  neighbor 2001:db8:4:17::4 activate
  neighbor 2001:db8:5:10::100 activate
 exit-address-family
!
end
wr

Verificando status do BGP

Nesse momento podemos ver as sessões BGP em cada Router. A sessão com nosso AS 64320 está como idle porque ainda não configuramos ele.

##################
### No Router1 ###
##################

router1_65001#show bgp ipv6 unicast summary
BGP router identifier 1.1.1.1, local AS number 65001
BGP table version is 6, main routing table version 6
5 network entries using 840 bytes of memory
6 path entries using 648 bytes of memory
6/5 BGP path/bestpath attribute entries using 960 bytes of memory
5 BGP AS-PATH entries using 120 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2568 total bytes of memory
BGP activity 5/0 prefixes, 6/0 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2001:DB8:1:10::100
                4        64320       0       0        1    0    0 never    Active
2001:DB8:1:17::2
                4        65002      29      29        6    0    0 00:21:51        2
2001:DB8:1:18::5
                4        65005      28      28        6    0    0 00:20:53        3



router1_65001#show bgp ipv6 unicast
BGP table version is 6, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
              t secondary path, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>   2001:DB8:1::/48  ::                       0         32768 i
 *>   2001:DB8:2::/48  2001:DB8:1:17::2
                                                0             0 65002 i
 *    2001:DB8:3::/48  2001:DB8:1:18::5
                                                              0 65005 65004 65003 i
 *>                    2001:DB8:1:17::2
                                                              0 65002 65003 i
 *    2001:DB8:4::/48  2001:DB8:1:17::2
                                                              0 65002 65003 65004 i
 *>                    2001:DB8:1:18::5
                                                              0 65005 65004 i
 *>   2001:DB8:5::/48  2001:DB8:1:18::5
     Network          Next Hop            Metric LocPrf Weight Path
                                                0             0 65005 i



router1_65001#show ipv6 route bgp 
IPv6 Routing Table - default - 13 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
       B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
       H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea
       IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       RL - RPL, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
       OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       la - LISP alt, lr - LISP site-registrations, ld - LISP dyn-eid
       lA - LISP away, a - Application
B   2001:DB8:2::/48 [20/0]
     via FE80::5200:FF:FE02:1, GigabitEthernet0/1
B   2001:DB8:3::/48 [20/0]
     via FE80::5200:FF:FE02:1, GigabitEthernet0/1
B   2001:DB8:4::/48 [20/0]
     via FE80::5200:FF:FE05:0, GigabitEthernet0/0
B   2001:DB8:5::/48 [20/0]
     via FE80::5200:FF:FE05:0, GigabitEthernet0/0



##################
### No Router2 ###
##################

router2_65002#show bgp ipv6 unicast summary
BGP router identifier 1.1.1.2, local AS number 65002
BGP table version is 7, main routing table version 7
5 network entries using 840 bytes of memory
7 path entries using 756 bytes of memory
7/5 BGP path/bestpath attribute entries using 1120 bytes of memory
6 BGP AS-PATH entries using 144 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2860 total bytes of memory
BGP activity 5/0 prefixes, 7/0 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2001:DB8:1:17::1
                4        65001      32      33        7    0    0 00:25:00        3
2001:DB8:2:10::100
                4        64320       0       0        1    0    0 never    Idle
2001:DB8:2:17::3
                4        65003      31      33        7    0    0 00:24:39        3



router2_65002#show bgp ipv6 unicast
BGP table version is 7, local router ID is 1.1.1.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
              t secondary path, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>   2001:DB8:1::/48  2001:DB8:1:17::1
                                                0             0 65001 i
 *>   2001:DB8:2::/48  ::                       0         32768 i
 *>   2001:DB8:3::/48  2001:DB8:2:17::3
                                                0             0 65003 i
 *>   2001:DB8:4::/48  2001:DB8:2:17::3
                                                              0 65003 65004 i
 *                     2001:DB8:1:17::1
                                                              0 65001 65005 65004 i
 *    2001:DB8:5::/48  2001:DB8:2:17::3
                                                              0 65003 65004 65005 i
     Network          Next Hop            Metric LocPrf Weight Path
 *>                    2001:DB8:1:17::1
                                                              0 65001 65005 i



router2_65002#show ipv6 route bgp
IPv6 Routing Table - default - 13 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
       B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
       H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea
       IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       RL - RPL, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
       OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       la - LISP alt, lr - LISP site-registrations, ld - LISP dyn-eid
       lA - LISP away, a - Application
B   2001:DB8:1::/48 [20/0]
     via FE80::5200:FF:FE01:1, GigabitEthernet0/1
B   2001:DB8:3::/48 [20/0]
     via FE80::5200:FF:FE04:1, GigabitEthernet0/0
B   2001:DB8:4::/48 [20/0]
     via FE80::5200:FF:FE04:1, GigabitEthernet0/0
B   2001:DB8:5::/48 [20/0]
     via FE80::5200:FF:FE01:1, GigabitEthernet0/1



##################
### No Router3 ###
##################

router3_65003#show bgp ipv6 unicast summary
BGP router identifier 1.1.1.3, local AS number 65003
BGP table version is 6, main routing table version 6
5 network entries using 840 bytes of memory
7 path entries using 756 bytes of memory
7/5 BGP path/bestpath attribute entries using 1120 bytes of memory
6 BGP AS-PATH entries using 144 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2860 total bytes of memory
BGP activity 5/0 prefixes, 8/1 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2001:DB8:2:17::2
                4        65002      34      33        6    0    0 00:25:45        3
2001:DB8:3:10::100
                4        64320       0       0        1    0    0 never    Idle
2001:DB8:3:17::4
                4        65004      33      33        6    0    0 00:25:24        3



router3_65003#show bgp ipv6 unicast
BGP table version is 6, local router ID is 1.1.1.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
              t secondary path, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *    2001:DB8:1::/48  2001:DB8:3:17::4
                                                              0 65004 65005 65001 i
 *>                    2001:DB8:2:17::2
                                                              0 65002 65001 i
 *>   2001:DB8:2::/48  2001:DB8:2:17::2
                                                0             0 65002 i
 *>   2001:DB8:3::/48  ::                       0         32768 i
 *>   2001:DB8:4::/48  2001:DB8:3:17::4
                                                0             0 65004 i
 *    2001:DB8:5::/48  2001:DB8:2:17::2
                                                              0 65002 65001 65005 i
     Network          Next Hop            Metric LocPrf Weight Path
 *>                    2001:DB8:3:17::4
                                                              0 65004 65005 i



router3_65003#show ipv6 route bgp
IPv6 Routing Table - default - 13 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
       B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
       H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea
       IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       RL - RPL, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
       OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       la - LISP alt, lr - LISP site-registrations, ld - LISP dyn-eid
       lA - LISP away, a - Application
B   2001:DB8:1::/48 [20/0]
     via FE80::5200:FF:FE02:0, GigabitEthernet0/1
B   2001:DB8:2::/48 [20/0]
     via FE80::5200:FF:FE02:0, GigabitEthernet0/1
B   2001:DB8:4::/48 [20/0]
     via FE80::5200:FF:FE06:1, GigabitEthernet0/0
B   2001:DB8:5::/48 [20/0]
     via FE80::5200:FF:FE06:1, GigabitEthernet0/0



##################
### No Router4 ###
##################

router4_65004#show bgp ipv6 unicast summary
BGP router identifier 1.1.1.4, local AS number 65004
BGP table version is 6, main routing table version 6
5 network entries using 840 bytes of memory
7 path entries using 756 bytes of memory
7/5 BGP path/bestpath attribute entries using 1120 bytes of memory
6 BGP AS-PATH entries using 144 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2860 total bytes of memory
BGP activity 5/0 prefixes, 7/0 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2001:DB8:3:17::3
                4        65003      34      34        6    0    0 00:26:34        3
2001:DB8:4:10::100
                4        64320       0       0        1    0    0 never    Active
2001:DB8:4:17::5
                4        65005      34      34        6    0    0 00:26:15        3



router4_65004#show bgp ipv6 unicast          
BGP table version is 6, local router ID is 1.1.1.4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
              t secondary path, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *    2001:DB8:1::/48  2001:DB8:3:17::3
                                                              0 65003 65002 65001 i
 *>                    2001:DB8:4:17::5
                                                              0 65005 65001 i
 *    2001:DB8:2::/48  2001:DB8:4:17::5
                                                              0 65005 65001 65002 i
 *>                    2001:DB8:3:17::3
                                                              0 65003 65002 i
 *>   2001:DB8:3::/48  2001:DB8:3:17::3
                                                0             0 65003 i
 *>   2001:DB8:4::/48  ::                       0         32768 i
 *>   2001:DB8:5::/48  2001:DB8:4:17::5
                                                0             0 65005 i



router4_65004#show ipv6 route bgp
IPv6 Routing Table - default - 13 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
       B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
       H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea
       IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       RL - RPL, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
       OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       la - LISP alt, lr - LISP site-registrations, ld - LISP dyn-eid
       lA - LISP away, a - Application
B   2001:DB8:1::/48 [20/0]
     via FE80::5200:FF:FE05:1, GigabitEthernet0/0
B   2001:DB8:2::/48 [20/0]
     via FE80::5200:FF:FE04:0, GigabitEthernet0/1
B   2001:DB8:3::/48 [20/0]
     via FE80::5200:FF:FE04:0, GigabitEthernet0/1
B   2001:DB8:5::/48 [20/0]
     via FE80::5200:FF:FE05:1, GigabitEthernet0/0



##################
### No Router5 ###
##################

router5_65005#show bgp ipv6 unicast summary
BGP router identifier 1.1.1.5, local AS number 65005
BGP table version is 6, main routing table version 6
5 network entries using 840 bytes of memory
7 path entries using 756 bytes of memory
7/5 BGP path/bestpath attribute entries using 1120 bytes of memory
6 BGP AS-PATH entries using 144 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2860 total bytes of memory
BGP activity 5/0 prefixes, 7/0 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2001:DB8:1:18::1
                4        65001      37      37        6    0    0 00:29:36        3
2001:DB8:4:17::4
                4        65004      38      37        6    0    0 00:29:35        3
2001:DB8:5:10::100
                4        64320       0       0        1    0    0 never    Idle



router5_65005#show bgp ipv6 unicast
BGP table version is 6, local router ID is 1.1.1.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
              x best-external, a additional-path, c RIB-compressed, 
              t secondary path, 
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>   2001:DB8:1::/48  2001:DB8:1:18::1
                                                0             0 65001 i
 *    2001:DB8:2::/48  2001:DB8:4:17::4
                                                              0 65004 65003 65002 i
 *>                    2001:DB8:1:18::1
                                                              0 65001 65002 i
 *    2001:DB8:3::/48  2001:DB8:1:18::1
                                                              0 65001 65002 65003 i
 *>                    2001:DB8:4:17::4
                                                              0 65004 65003 i
 *>   2001:DB8:4::/48  2001:DB8:4:17::4
                                                0             0 65004 i
 *>   2001:DB8:5::/48  ::                       0         32768 i



router5_65005#show ipv6 route bgp
IPv6 Routing Table - default - 13 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
       B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
       H - NHRP, I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea
       IS - ISIS summary, D - EIGRP, EX - EIGRP external, NM - NEMO
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       RL - RPL, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
       OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       la - LISP alt, lr - LISP site-registrations, ld - LISP dyn-eid
       lA - LISP away, a - Application
B   2001:DB8:1::/48 [20/0]
     via FE80::5200:FF:FE01:0, GigabitEthernet0/0
B   2001:DB8:2::/48 [20/0]
     via FE80::5200:FF:FE01:0, GigabitEthernet0/0
B   2001:DB8:3::/48 [20/0]
     via FE80::5200:FF:FE06:0, GigabitEthernet0/1
B   2001:DB8:4::/48 [20/0]
     via FE80::5200:FF:FE06:0, GigabitEthernet0/1

Configurando nosso AS 64320

Agora vamos configurar nosso roteador que está dentro das redes dos provedores.

###################################
### Roteador na rede do Router1 ###
###################################
enable
!
terminal length 0
!
conf t
!
hostname router1_anycast_64320
!
ipv6 unicast-routing
!
interface GigabitEthernet0/0
 description servidor anycast
 ipv6 address 2001:db8:ffff::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:ffff::/64 1800 1800
 ipv6 nd prefix default
 no shut
!
interface GigabitEthernet0/1
 description Rede do ISP
 ipv6 address 2001:db8:1:10::100/64
 ipv6 enable
 no shut
!
router bgp 64320
 bgp router-id 100.100.100.100
 no bgp default ipv4-unicast
 neighbor 2001:db8:1:10::1 remote-as 65001
 !
 address-family ipv6
  network 2001:db8:ffff::/64
  neighbor 2001:db8:1:10::1 activate
 exit-address-family
!
end
wr



###################################
### Roteador na rede do Router2 ###
###################################
enable
!
terminal length 0
!
conf t
!
hostname router2_anycast_64320
!
ipv6 unicast-routing
!
interface GigabitEthernet0/0
 description servidor anycast
 ipv6 address 2001:db8:ffff::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:ffff::/64 1800 1800
 ipv6 nd prefix default
 no shut
!
interface GigabitEthernet0/1
 description Rede do ISP
 ipv6 address 2001:db8:2:10::100/64
 ipv6 enable
 no shut
!
router bgp 64320
 bgp router-id 100.100.100.100
 no bgp default ipv4-unicast
 neighbor 2001:db8:2:10::1 remote-as 65002
 !
 address-family ipv6
  network 2001:db8:ffff::/64
  neighbor 2001:db8:2:10::1 activate
 exit-address-family
!
end
wr



###################################
### Roteador na rede do Router4 ###
###################################
enable
!
terminal length 0
!
conf t
!
hostname router4_anycast_64320
!
ipv6 unicast-routing
!
interface GigabitEthernet0/0
 description servidor anycast
 ipv6 address 2001:db8:ffff::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:ffff::/64 1800 1800
 ipv6 nd prefix default
 no shut
!
interface GigabitEthernet0/1
 description Rede do ISP
 ipv6 address 2001:db8:4:10::100/64
 ipv6 enable
 no shut
!
router bgp 64320
 bgp router-id 100.100.100.100
 no bgp default ipv4-unicast
 neighbor 2001:db8:4:10::1 remote-as 65004
 !
 address-family ipv6
  network 2001:db8:ffff::/64
  neighbor 2001:db8:4:10::1 activate
 exit-address-family
!
end
wr



###################################
### Roteador na rede do Router5 ###
###################################
enable
!
terminal length 0
!
conf t
!
hostname router5_anycast_64320
!
ipv6 unicast-routing
!
interface GigabitEthernet0/0
 description servidor anycast
 ipv6 address 2001:db8:ffff::1/64
 ipv6 enable
 ipv6 nd ra interval 30
 ipv6 nd prefix 2001:db8:ffff::/64 1800 1800
 ipv6 nd prefix default
 no shut
!
interface GigabitEthernet0/1
 description Rede do ISP
 ipv6 address 2001:db8:5:10::100/64
 ipv6 enable
 no shut
!
router bgp 64320
 bgp router-id 100.100.100.100
 no bgp default ipv4-unicast
 neighbor 2001:db8:5:10::1 remote-as 65005
 !
 address-family ipv6
  network 2001:db8:ffff::/64
  neighbor 2001:db8:5:10::1 activate
 exit-address-family
!
end
wr

Verificando o prefixo do anycast

Vamos ver o anuncio da rede do anycast em todos os routers:

##################
### No Router1 ###
##################

router1_65001#show bgp ipv6 unicast 2001:db8:ffff::/64 longer-prefixes | begin Network
     Network          Next Hop            Metric LocPrf Weight Path
 *    2001:DB8:FFFF::/64
                       2001:DB8:1:17::2
                                                              0 65002 64320 i
 *                     2001:DB8:1:18::5
                                                              0 65005 64320 i
 *>                    2001:DB8:1:10::100
                                                0             0 64320 i



##################
### No Router2 ###
##################

router2_65002#show bgp ipv6 unicast 2001:db8:ffff::/64 longer-prefixes | begin Network
     Network          Next Hop            Metric LocPrf Weight Path
 *>   2001:DB8:FFFF::/64
                       2001:DB8:2:10::100
                                                0             0 64320 i
 *                     2001:DB8:2:17::3
                                                              0 65003 65004 64320 i
 *                     2001:DB8:1:17::1
                                                              0 65001 64320 i




##################
### No Router3 ###
##################

router3_65003#show bgp ipv6 unicast 2001:db8:ffff::/64 longer-prefixes | begin Network
     Network          Next Hop            Metric LocPrf Weight Path
 *>   2001:DB8:FFFF::/64
                       2001:DB8:3:17::4
                                                              0 65004 64320 i
 *                     2001:DB8:2:17::2
                                                              0 65002 64320 i



##################
### No Router4 ###
##################

router4_65004#show bgp ipv6 unicast 2001:db8:ffff::/64 longer-prefixes | begin Network
     Network          Next Hop            Metric LocPrf Weight Path
 *>   2001:DB8:FFFF::/64
                       2001:DB8:4:10::100
                                                0             0 64320 i
 *                     2001:DB8:4:17::5
                                                              0 65005 64320 i



##################
### No Router5 ###
##################

router5_65005#show bgp ipv6 unicast 2001:db8:ffff::/64 longer-prefixes | begin Network
     Network          Next Hop            Metric LocPrf Weight Path
 *    2001:DB8:FFFF::/64
                       2001:DB8:4:17::4
                                                              0 65004 64320 i
 *>                    2001:DB8:5:10::100
                                                0             0 64320 i
 *                     2001:DB8:1:18::1
                                                              0 65001 64320 i

Configurando o servidor Ubuntu

Todos os servidores Ubuntu localizados no ASN 64320 devem ser configurados com a seguinte configuração de rede, utilizando Netplan (porque é um Ubuntu):

cat << 'EOF' > /etc/netplan/50-cloud-init.yaml
network:
  version: 2
  ethernets:
    eth0:
      addresses:
        - 2001:db8:ffff::100/128
      routes:
        - to: ::/0
          via: 2001:db8:ffff::1
          on-link: true
          scope: link
      accept-ra: no
EOF

netplan apply

Essa configuração atribui ao servidor o IP 2001:db8:ffff::100/128 e define uma rota default via o gateway 2001:db8:ffff::1, que é o roteador local no ASN 64320. O parâmetro on-link: true é essencial para permitir o uso de um endereço de gateway que pertence à mesma sub-rede sem depender de descoberta de vizinhança. Além disso, accept-ra: no desabilita o recebimento de anúncios de rota via RA, garantindo controle total da configuração estática.

Podemos realizar um teste com mtr a partir de um cliente localizado atrás do roteador3_65003, com destino ao IP anycast do servidor:

ipv4_mapeado

A imagem acima mostra o caminho percorrido até o servidor anycast, confirmando que a topologia está roteando corretamente os pacotes para o ASN mais próximo.

Introdução​

Switches​

Router 1​

Router 2​

Router 3​

Router 4​

Router 5​

Verificando status do BGP​

Configurando nosso AS 64320​

Verificando o prefixo do anycast​

Configurando o servidor Ubuntu​