IPv6 - 6PE

1. Introduction

Le lab suivant présente rapidement le fonctionnement de 6PE.
En prérequis, un coeur de réseau IPv4 MPLS constitue le backbone de l'opérateur.
Sur les équipements P (P1 dans le schéma ci-dessous), IPv6 n'est pas activé (ipv6 unicast-routing).
2. Configuration du coeur MPLS IPv4
6PE1:

!
hostname 6PE1
!
interface Loopback0
ip address 10.0.0.2 255.255.255.255
no clns route-cache
!
interface Serial1/1
description ## R2-R3 ##
ip address 192.168.23.2 255.255.255.0
ip router isis
mpls ip
serial restart-delay 0
!
router isis
net 49.0000.0000.0002.00
passive-interface Loopback0
!

6PE2:

!
hostname 6PE2
!
interface Loopback0
ip address 10.0.0.4 255.255.255.255
no clns route-cache
!
interface Serial1/3
description ## R4-R3 ##
ip address 192.168.34.4 255.255.255.0
ip router isis
mpls ip
serial restart-delay 0
!
router isis
net 49.0000.0000.0004.00
passive-interface Loopback0
!

P1:

!
hostname P1
!
interface Loopback0
ip address 10.0.0.3 255.255.255.255
no clns route-cache
!
interface Serial1/1
description ## R2-R3 ##
ip address 192.168.23.3 255.255.255.0
ip router isis
mpls ip
serial restart-delay 0
!
interface Serial1/2
description ## R3-R4 ##
ip address 192.168.34.3 255.255.255.0
ip router isis
mpls ip
serial restart-delay 0
!
router isis
net 49.0000.0000.0002.00
passive-interface Loopback0
!

3. Connexion des CE IPv6 aux 6PE:

6PE1:

!
ipv6 unicast-routing
ipv6 cef
!
interface Serial1/0
no ip address
ipv6 address 3FFE:B00:FFFF::2/48
no fair-queue
serial restart-delay 0
no clns route-cache
!

CE1:

!
ipv6 unicast-routing
ipv6 cef
!
interface Serial1/0
no ip address
ipv6 address 3FFE:B00:FFFF::1/48
no fair-queue
serial restart-delay 0
no clns route-cache
!
ipv6 route ::/0 Serial1/0 3FFE:B00:FFFF::2
!

6PE2:

!
ipv6 unicast-routing
ipv6 cef
!
interface Serial1/3
no ip address
ipv6 address 3FFE:B00:DDDD::2/48
no fair-queue
serial restart-delay 0
no clns route-cache
!

CE2:

!
ipv6 unicast-routing
ipv6 cef
!
interface Serial1/3
no ip address
ipv6 address 3FFE:B00:DDDD::1/48
no fair-queue
serial restart-delay 0
no clns route-cache
!
ipv6 route ::/0 Serial1/0 3FFE:B00:DDDD::2
!

4. Configuration des 6PE pour l'échange des préfixes

Le cœur n'est pas configuré pour IPv6, on se sert des labels.
Une session MP-iBGP est configurée entre les deux '6PE':

6PE1:

!
router bgp 10
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 10.0.0.4 remote-as 10
neighbor 10.0.0.4 update-source Loopback0
!
address-family ipv6
neighbor 10.0.0.4 activate
neighbor 10.0.0.4 send-label
network 3FFE:B00:FFFF::/48
exit-address-family
!

6PE2:

!
router bgp 10
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 10.0.0.2 remote-as 10
neighbor 10.0.0.2 update-source Loopback0
!
address-family ipv6
neighbor 10.0.0.2 activate
neighbor 10.0.0.2 send-label
network 3FFE:B00:DDDD::/48
exit-address-family
!

5. Résultats et interprétations

Les networks IPv6 vers les CE1 et CE2 sont annoncés par leur PE respectifs.
Le next hop est de la forme ::FFFF:10.0.0.2, 10.0.0.2 est l'interface update source de la session MP-BGP vers 6PE1:

6PE2#show ip bgp ipv6 unicast
BGP table version is 7, local router ID is 10.0.0.4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete


Network Next Hop Metric LocPrf Weight Path
*> 3FFE:B00:DDDD::/48 :: 0 32768 i
*>i3FFE:B00:FFFF::/48 ::FFFF:10.0.0.2 0 100 0 i
6PE2#

Le prefixe vers CE2 est présent dans la RIB IPv6:

6PE2#show ipv6 route
IPv6 Routing Table - 5 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, IS - ISIS summary
O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
C 3FFE:B00:DDDD::/48 [0/0]
via ::, Serial1/3
L 3FFE:B00:DDDD::2/128 [0/0]
via ::, Serial1/3
B 3FFE:B00:FFFF::/48 [200/0]
via ::FFFF:10.0.0.2
L FE80::/10 [0/0]
via ::, Null0
L FF00::/8 [0/0]
via ::, Null0
6PE2#

Le process BGP de 6PE2 génère un label pour le prefixe qu'il annonce, et le remonte dans la LFIB:

6PE2#show mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or VC or Tunnel Id Switched interface
16 16 10.0.0.2/32 0 Se1/2 point2point
17 Pop Label 10.0.0.3/32 0 Se1/2 point2point
18 Pop Label 192.168.23.0/24 0 Se1/2 point2point
19 Aggregate 101.101.101.4/32[V] \
0 CustIPv4
20 No Label 3FFE:B00:DDDD::/48 \
2080 Se1/3 point2point
6PE2#

Le next-hop annoncé par la session MP-iBGP est 10.0.0.2, ldp annonce le label 16 pour ce préfixe.

6PE2#show ipv6 cef 3FFE:B00:FFFF::/48
3FFE:B00:FFFF::/48
nexthop 192.168.34.3 Serial1/2 label 16 20
6PE2#

Pour le second PE, le principe est identique:

6PE1#show ip bgp ipv6 unicast
BGP table version is 7, local router ID is 10.0.0.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*>i3FFE:B00:DDDD::/48
::FFFF:10.0.0.4 0 100 0 i
*> 3FFE:B00:FFFF::/48
:: 0 32768 i
6PE1#

6PE1#show ipv6 route
IPv6 Routing Table - 5 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, IS - ISIS summary
O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
B 3FFE:B00:DDDD::/48 [200/0]
via ::FFFF:10.0.0.4
C 3FFE:B00:FFFF::/48 [0/0]
via ::, Serial1/0
L 3FFE:B00:FFFF::2/128 [0/0]
via ::, Serial1/0
L FE80::/10 [0/0]
via ::, Null0
L FF00::/8 [0/0]
via ::, Null0
6PE1#

6PE1#show mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or VC or Tunnel Id Switched interface
16 Pop Label 10.0.0.3/32 0 Se1/1 point2point
17 17 10.0.0.4/32 0 Se1/1 point2point
18 Pop Label 192.168.34.0/24 0 Se1/1 point2point
20 Aggregate 3FFE:B00:FFFF::/48 \
0
6PE1#

6PE1#sh ipv6 cef
3FFE:B00:DDDD::/48
nexthop 192.168.23.3 Serial1/1 label 17 20
3FFE:B00:FFFF::/48
attached to Serial1/0
3FFE:B00:FFFF::2/128
receive
FE80::/10
receive
FF00::/8
receive
6PE1#