sábado, 4 de setembro de 2010

Traffic Engineering - ISIS com Forward Adjacency


1        Cenário

1.1           Objetivo

Sete roteadores (R1, R2, R3, R4, R5, R6 e R7) são conectados fisicamente conforme a topologia abaixo via interfaces Fast Ethernet. Pede-se as configurações abaixo:
         Deverá ser usado o encaminhamento via MPLS entre todos os roteadores;
         O Router-ID do MPLS deve ser o IP da loopback 0 de cada roteador;
         Um túnel MPLS deverá ser criado no R2 para o R7 usando Traffic Engineer para encaminhamento de tráfego.
         Um túnel MPLS deverá ser criado no R5 para o R7 usando Traffic Engineer para encaminhamento de tráfego.
         O R7 deverá ter 2 túneis, um para R2 e outro para R5 com encaminhamento de tráfego.
         OS túneis deverão ser dinâmicos.
         O protocolo de roteamento deverá ser o ISIS somente no level-2 na área 49.9999.

1.2           Topologia


Figure-01:              Topologia

1.3           IOS utilizados

         R1, R2, R3, R4, R5, R6 e R7 – c7200-k91p-mz.122-25.S15.bin

1.4           Configuração dos Roteadores

1.4.1      Configurações do ISIS

Em todos os roteadores configura-se o roteamento ISIS adicionando o endereçamento NET de acordo com a área designada e endereçamento de loopback. Dentro das interfaces que farão parte do ISIS, adiciona-se o comando “ip router isis” para habilitar o ISIS na interface. Por padrão, todos os roteadores farão vizinhança L1/L2, para alterar, usa-se o comando “is-type level-2-only”.

1.4.2      Configurações do MPLS

Antes de qualquer configuração, o Cisco Express forwarding deve ser habilitado com o comando “ip cef”. Para habilitar o MPLS no modo LDP, usa-se o comando global “mpls label protocol ldp”, para que seja habilitado nas interfaces, usa-se esse comando dentro da interface.
O Router-ID usado no MPLS pode ser configurado com o comando “mpls ldp router-id ”. A configuração do escopo dos labels que serão usados pelo roteador no MPLS é feita com o comando “mpls label range .

1.4.3      Configurações do Túnel de TE com ISIS entre Levels

Para configurar um túnel MPLS TE inicialmente cria-se a interface túnel com o comando “interface tunnel ”, dentro da interface adiciona-se um endereçamento IP, geralmente usa-se um endereço da loopback com o comando “ip unnumbered Loopback0”. Em seguida configura-se o IP do roteador de destino para o fechamento do túnel com o comando “tunnel destination ”. Aplica-se então o modo de túnel como MPLS com TE com o comando “tunnel mode mpls traffic-eng”, e após, habilita-se o caminho pelo túnel com o comando “tunnel mpls traffic-eng path-option dynamic”, onde o “dynamic” pode também ser “explict” que define um caminho específico.
Para o uso do MPLS TE aplica-se globalmente o comando “mpls traffic-eng tunnels”, em todas as interfaces, adiciona-se o comando “mpls traffic-eng tunnels”, esse comando permite a sinalização de TE nas interfaces.
Dentro do protocolo ISIS deve ser adicionada a loopback do router-ID para Traffic-Engineer com o comando “mpls traffic-eng router-id Loopback0” e habilitar o TE para o level de roteamento ISIS “mpls traffic-eng level-2, configura-se os dois levels no traffic-eng caso o roteador seja L1/L2.

1.4.4      Encaminhamento pelo Túnel (Forward Adjacency)

Para habilitar o túnel para encaminhar tráfego originados em outro roteador usa-se o comando “tunnel mpls traffic-eng forwarding-adjacency” dentro da interface túnel.

1.5           Observações e Bugs

Documentação:

1.6           Comandos Importantes de Verificação

R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     34.0.0.0/24 is subnetted, 1 subnets
i L2    34.34.34.0 [115/30] via 12.12.12.2, FastEthernet0/0
     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback0
     2.0.0.0/32 is subnetted, 1 subnets
i L2    2.2.2.2 [115/20] via 12.12.12.2, FastEthernet0/0
     3.0.0.0/32 is subnetted, 1 subnets
i L2    3.3.3.3 [115/30] via 12.12.12.2, FastEthernet0/0
     4.0.0.0/32 is subnetted, 1 subnets
i L2    4.4.4.4 [115/40] via 15.15.15.5, FastEthernet1/0
                [115/40] via 12.12.12.2, FastEthernet0/0
     5.0.0.0/32 is subnetted, 1 subnets
i L2    5.5.5.5 [115/20] via 15.15.15.5, FastEthernet1/0
     6.0.0.0/32 is subnetted, 1 subnets
i L2    6.6.6.6 [115/30] via 15.15.15.5, FastEthernet1/0
     23.0.0.0/24 is subnetted, 1 subnets
i L2    23.23.23.0 [115/20] via 12.12.12.2, FastEthernet0/0
     67.0.0.0/24 is subnetted, 1 subnets
i L2    67.67.67.0 [115/30] via 15.15.15.5, FastEthernet1/0
                   [115/30] via 12.12.12.2, FastEthernet0/0
     7.0.0.0/32 is subnetted, 1 subnets
i L2    7.7.7.7 [115/30] via 15.15.15.5, FastEthernet1/0
                [115/30] via 12.12.12.2, FastEthernet0/0
     56.0.0.0/24 is subnetted, 1 subnets
i L2    56.56.56.0 [115/20] via 15.15.15.5, FastEthernet1/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, FastEthernet0/0
     47.0.0.0/24 is subnetted, 1 subnets
i L2    47.47.47.0 [115/30] via 15.15.15.5, FastEthernet1/0
                   [115/30] via 12.12.12.2, FastEthernet0/0
     15.0.0.0/24 is subnetted, 1 subnets
C       15.15.15.0 is directly connected, FastEthernet1/0

R7#show mpls forwarding-table
Local  Outgoing      Prefix            Bytes Label   Outgoing   Next Hop   
Label  Label or VC   or Tunnel Id      Switched      interface             
16     Pop Label     4.4.4.4/32        0             Fa0/0      47.47.47.4 
17     16            3.3.3.3/32        0             Fa0/0      47.47.47.4 
18     Pop Label     34.34.34.0/24     0             Fa0/0      47.47.47.4 
19     No Label  [T] 23.23.23.0/24     0             Tu27       point2point
20     Pop Label     6.6.6.6/32        0             Fa1/0      67.67.67.6 
21     Pop Label [T] 5.5.5.5/32        0             Tu57       point2point
22     No Label  [T] 1.1.1.1/32        0             Tu27       point2point
23     Pop Label [T] 2.2.2.2/32        0             Tu27       point2point
24     Pop Label     56.56.56.0/24     0             Fa1/0      67.67.67.6 
25     No Label  [T] 15.15.15.0/24     0             Tu57       point2point
26     No Label  [T] 12.12.12.0/24     0             Tu27       point2point

[T]     Forwarding through a TSP tunnel.
        View additional labelling info with the 'detail' option

2        Configuração

2.1           R1

!
ip cef
!
mpls label protocol ldp
mpls ldp router-id Loopback0
mpls traffic-eng tunnels
!
!
interface Loopback0
 ip address 1.1.1.1 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 12.12.12.1 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 15.15.15.1 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0001.00
 is-type level-2-only
 metric-style wide
!

2.2           R2

ip cef
!
mpls label protocol ldp
!
mpls traffic-eng tunnels
mpls ldp router-id Loopback0
!
interface Tunnel27
 ip unnumbered Loopback0
 tunnel destination 7.7.7.7
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng forwarding-adjacency
 tunnel mpls traffic-eng path-option 1 dynamic
!
interface Loopback0
 ip address 2.2.2.2 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 12.12.12.2 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 23.23.23.2 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0002.00
 is-type level-2-only
 metric-style wide
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
!

2.3           R3

!
ip cef
!
mpls traffic-eng tunnels
mpls label protocol ldp
mpls ldp router-id Loopback0
!
interface Loopback0
 ip address 3.3.3.3 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 23.23.23.3 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 34.34.34.3 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0003.00
 is-type level-2-only
 metric-style wide
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
!

2.4           R4

!
ip cef
!
mpls label protocol ldp
mpls traffic-eng tunnels
mpls ldp router-id Loopback0
!
interface Loopback0
 ip address 4.4.4.4 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 34.34.34.4 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 47.47.47.4 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0004.00
 is-type level-2-only
 metric-style transition
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
!

2.5           R5

!
ip cef
!
mpls label protocol ldp
mpls traffic-eng tunnels
mpls ldp router-id Loopback0
!
interface Tunnel57
 ip unnumbered Loopback0
 tunnel destination 7.7.7.7
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng forwarding-adjacency
 tunnel mpls traffic-eng path-option 1 dynamic
!
interface Loopback0
 ip address 5.5.5.5 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 15.15.15.5 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 56.56.56.5 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0005.00
 is-type level-2-only
 metric-style wide
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
!

2.6           R6

!
ip cef
!
mpls label protocol ldp
mpls traffic-eng tunnels
mpls ldp router-id Loopback0
!
interface Loopback0
 ip address 6.6.6.6 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 67.67.67.6 255.255.255.0
 ip router isis
 duplex full
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 56.56.56.6 255.255.255.0
 ip router isis
 duplex full
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0006.00
 is-type level-2-only
 metric-style transition
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
!

2.7           R7

!
ip cef
!
mpls label protocol ldp
mpls traffic-eng tunnels
mpls ldp router-id Loopback0
!
interface Tunnel27
 ip unnumbered Loopback0
 tunnel destination 2.2.2.2
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng forwarding-adjacency
 tunnel mpls traffic-eng path-option 1 dynamic
 no clns route-cache
!
interface Tunnel57
 ip unnumbered Loopback0
 tunnel destination 5.5.5.5
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng forwarding-adjacency
 tunnel mpls traffic-eng path-option 1 dynamic
 no clns route-cache
!
interface Loopback0
 ip address 7.7.7.7 255.255.255.255
 ip router isis
!
interface FastEthernet0/0
 ip address 47.47.47.7 255.255.255.0
 ip router isis
 mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
interface FastEthernet1/0
 ip address 67.67.67.7 255.255.255.0
 ip router isis
  mpls traffic-eng tunnels
 mpls ip
 ip rsvp bandwidth
!
router isis
 net 49.9999.0000.0000.0007.00
 is-type level-2-only
 metric-style wide
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
!

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