Sunday, February 7, 2016

L3VPN task #7. Inter-AS L3VPN - part 2.

Topology:



Use configuration from L3VPN task #6 as initial configuration for this task.

Requirements: 

1. Service Providers X and Y are expecting a large amount of L3VPN customers to be connected in the future, similar to Customer A (Inter-AS L3VPN). Change the solution to improve the scalability and reduce the provisioning overhead. 
2. Customer's traffic should be labeled "end-to-end". 
3. Service Providers has agreed to coordinate the route-target values. For Customer A, use route-target 10:10. 
4. In order to reduce downtime, configuration change shall affect the minimal number of devices. 


Solution:

Highlight the text below to reveal the solution.

This task requires understanding of Inter-AS L3VPN configuration Options 10B and 10C.
Requirements #1, 2 and 3 can be satisfied with either option 10B or option 10C configuration. Both options 10B and 10C improve the scalability and reduce the configuration overhead, since there is no need to configure a dedicated connection on ASBR for each VFR that requires Inter-AS service. Both results in "end-to-end" LSP for customers traffic.

Requirement #4 - implementing option 10B only requires to update the configuration on ASBR routers, and change the route-target value on R6. option 10C would require also to alter the configuration of Route-reflector routers R2 and R5.

Note: 
* In IOS,  there are two options to implement the Option 10B configuration on ASBR. 
First option is to use "next-hop-self" on VPNv4 iBGP sessions. 
Second option is to configure "redistribute connected" into the IGP. This will result in allocating a label for VPNv4 eBGP peer, because host route to the peer is automatically created once session is established. This solution uses the second option. 
* In IOS-XR, the only option is to configure "next-hop-self" on VPNv4 iBGP sessions. In addition, on ASBR, you must configure a static host route towards the neighbor eBGP peer address. 


R3:


!
router static
 address-family ipv4 unicast
  19.0.34.4/32 GigabitEthernet0/0/0/2
 !
!
router bgp 19
 address-family vpnv4 unicast
  retain route-target all
 !
 neighbor 19.0.2.2
  remote-as 19
  update-source Loopback0
  address-family vpnv4 unicast
   next-hop-self
  !
 !
 neighbor 19.0.34.4
  remote-as 20
  address-family vpnv4 unicast
   route-policy ANY in
   route-policy ANY out
  !
 !
!


R4:

router static
 address-family ipv4 unicast
  19.0.34.3/32 GigabitEthernet0/0/0/2
 !
!
router bgp 20
 address-family vpnv4 unicast
  retain route-target all
 !
 neighbor 20.0.5.5
  remote-as 20
  update-source Loopback0
  address-family vpnv4 unicast
   route-policy HIGH_LP out
   next-hop-self
  !
 !
 neighbor 19.0.34.3
  remote-as 19
  address-family vpnv4 unicast
   route-policy ANY in
   route-policy ANY out
  !
 !
!


R7:


!
router isis AS20
 mpls ldp autoconfig
 net 49.0020.0000.0000.0007.00
 is-type level-2-only
 redistribute connected
!
router bgp 20
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 no bgp default route-target filter
 neighbor 20.0.5.5 remote-as 20
 neighbor 20.0.5.5 update-source Loopback0
 neighbor 20.0.79.9 remote-as 19
 !
 address-family ipv4
 exit-address-family
 !
 address-family vpnv4
  neighbor 20.0.5.5 activate
  neighbor 20.0.5.5 send-community both
  neighbor 20.0.79.9 activate
  neighbor 20.0.79.9 send-community both
 exit-address-family
!

R9:




!
router ospf 1
 mpls ldp autoconfig
 router-id 19.0.9.9
 redistribute connected subnets
!
router bgp 19
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 no bgp default route-target filter
 neighbor 19.0.2.2 remote-as 19
 neighbor 19.0.2.2 update-source Loopback0
 neighbor 20.0.79.7 remote-as 20
 !
 address-family ipv4
 exit-address-family
 !
 address-family vpnv4
  neighbor 19.0.2.2 activate
  neighbor 19.0.2.2 send-community both
  neighbor 19.0.2.2 route-map HIGH_LP out
  neighbor 20.0.79.7 activate
  neighbor 20.0.79.7 send-community both
 exit-address-family
!


Verification:


R10#traceroute 10.10.11.11 source lo0
Type escape sequence to abort.
Tracing the route to 10.10.11.11
VRF info: (vrf in name/id, vrf out name/id)
  1 19.0.10.1 6 msec 4 msec 4 msec
  2 19.0.12.2 [MPLS: Labels 20/22 Exp 0] 2 msec 2 msec 1 msec
  3 19.0.29.9 [MPLS: Labels 23/22 Exp 0] 1 msec 1 msec 1 msec
  4 20.0.79.7 [MPLS: Label 22 Exp 0] 1 msec 1 msec 1 msec
  5 20.0.57.5 [MPLS: Labels 17/21 Exp 0] 2 msec 2 msec 1 msec
  6 20.0.11.6 [MPLS: Label 21 Exp 0] 1 msec 2 msec 2 msec
  7 20.0.11.11 1 msec 2 msec 2 msec


R11#traceroute 10.10.10.10 source lo0
Type escape sequence to abort.
Tracing the route to 10.10.10.10
VRF info: (vrf in name/id, vrf out name/id)
  1 20.0.11.6 5 msec 5 msec 4 msec
  2 20.0.56.5 [MPLS: Labels 16/16008 Exp 0] 2 msec 2 msec 2 msec
  3 20.0.45.4 [MPLS: Label 16008 Exp 0] 2 msec 2 msec 1 msec
  4 19.0.34.3 [MPLS: Label 16008 Exp 0] 1 msec 2 msec 1 msec
  5 19.0.23.2 [MPLS: Labels 18/21 Exp 0] 2 msec 2 msec 1 msec
  6 19.0.10.1 [MPLS: Label 21 Exp 0] 1 msec 2 msec 1 msec
  7 19.0.10.10 2 msec 2 msec 1 msec


R1#show mpls forwarding-table
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
16         16         19.0.9.9/32      0             Et0/0      19.0.12.2
17         17         19.0.3.3/32      0             Et0/0      19.0.12.2
18         Pop Label  19.0.2.2/32      0             Et0/0      19.0.12.2
19         Pop Label  19.0.29.0/24     0             Et0/0      19.0.12.2
20         Pop Label  19.0.23.0/24     0             Et0/0      19.0.12.2
21         No Label   10.10.10.0/24[V] 365400        Et1/0      19.0.10.10
22         No Label   19.0.10.0/24[V]  231436        aggregate/CUST_A
23         19         20.0.79.0/24     0             Et0/0      19.0.12.2
24         20         20.0.79.7/32     0             Et0/0      19.0.12.2
25         21         19.0.34.0/24     0             Et0/0      19.0.12.2

R9#       show mpls forwarding-table
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
16         17         19.0.3.3/32      0             Et0/0      19.0.29.2
17         Pop Label  19.0.2.2/32      0             Et0/0      19.0.29.2
18         Pop Label  19.0.23.0/24     0             Et0/0      19.0.29.2
19         Pop Label  19.0.12.0/24     0             Et0/0      19.0.29.2
20         18         19.0.1.1/32      0             Et0/0      19.0.29.2
21         21         10:10:10.10.10.0/24   \
                                       43654         Et0/0      19.0.29.2
22         22         10:10:19.0.10.0/24   \
                                       194886        Et0/0      19.0.29.2
23         Pop Label  20.0.79.7/32     29624         Et1/0.11   20.0.79.7
24         22         10:10:10.10.11.0/24   \
                                       24618         Et1/0.11   20.0.79.7
25         23         10:10:20.0.11.0/24   \
                                       0             Et1/0.11   20.0.79.7
26         21         19.0.34.0/24     0             Et0/0      19.0.29.2



R7#              show mpls forwarding-table
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
16         Pop Label  20.0.5.5/32      0             Et0/0      20.0.57.5
17         17         20.0.6.6/32      0             Et0/0      20.0.57.5
18         Pop Label  20.0.45.0/24     0             Et0/0      20.0.57.5
19         Pop Label  20.0.56.0/24     0             Et0/0      20.0.57.5
20         16         20.0.4.4/32      0             Et0/0      20.0.57.5
21         Pop Label  20.0.79.9/32     38546         Et1/0.11   20.0.79.9
22         21         10:10:10.10.11.0/24   \
                                       58762         Et0/0      20.0.57.5
23         22         10:10:20.0.11.0/24   \
                                       0             Et0/0      20.0.57.5
24         16008      10:10:10.10.10.0/24   \
                                       0             Et0/0      20.0.57.5
25         16010      10:10:19.0.10.0/24   \
                                       0             Et0/0      20.0.57.5
26         21         19.0.34.0/24     0             Et0/0      20.0.57.5

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