Configureer VRF-lekken op IOS XE

Inleiding

Dit document beschrijft en biedt voorbeeldconfiguraties voor veelgebruikte methoden voor het lekken van VRF-routes (Virtual Routing and Forwarding).

Voorwaarden

Vereisten

Cisco raadt kennis van de volgende onderwerpen aan:

• Border Gateway Protocol (BGP)
• herverdeling van routeringsprotocollen
• VRF
• Cisco IOS® XE-software

Voor meer informatie over deze onderwerpen, zie:

Routeringsprotocollen herverdelen

Wederzijdse herverdeling tussen EIGRP en BGP Configuratie Voorbeeld

Herverdeling van OSPF-routes naar BGP begrijpen

Gebruikte componenten

De informatie in dit document is gebaseerd op Routers met Cisco IOS® XE-versies 16.12.X en 17.X

De informatie in dit document is gebaseerd op de apparaten in een specifieke laboratoriumomgeving. Alle apparaten die in dit document worden beschreven, hadden een opgeschoonde (standaard)configuratie. Als uw netwerk live is, moet u zorgen dat u de potentiële impact van elke opdracht begrijpt.

Achtergrondinformatie

Met VRF kan een router afzonderlijke routeringstabellen voor verschillende virtuele netwerken onderhouden. Wanneer uitzonderingen nodig zijn, kan via het lekken van de VRF-route een deel van het verkeer tussen de VRF's worden geleid zonder gebruik te maken van statische routes.

Scenario 1 - Lek in VRF-route tussen BGP en IGP ( EIGRP )

Scenario 1 geeft een voorbeeld van een VRF-route die lekt tussen BGP en EIGRP. Deze methode kan worden gebruikt voor andere IGP's.

Netwerkdiagram

Het netwerkdiagram zoals te zien in afbeelding 1 toont de laag 3-topologie waar routelekkage nodig is.


Afbeelding 1. Route lekkende topologie voor scenario 1

Router LEAK heeft een BGP-buurt voor een buur in VRF A en een EIGRP-buur in de wereldwijde VRF. Apparaat 192.168.11.11 moet verbinding kunnen maken met apparaat 172.16.10.10 in het hele netwerk.

Router LEAK kan niet routeren tussen de twee omdat de routes in verschillende VRF's zijn.  Deze routeringstabellen tonen de huidige routes per VRF en geven aan welke routes moeten worden gelekt tussen de wereldwijde VRF en VRF A.

LEK routeringstabellen:

LEAK#show ip route 
Codes: L - local, 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, m - OMP
n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA
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
H - NHRP, G - NHRP registered, g - NHRP registration summary
o - ODR, P - periodic downloaded static route, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, GigabitEthernet2
L 192.168.1.1/32 is directly connected, GigabitEthernet2
192.168.11.0/32 is subnetted, 1 subnets
D 192.168.11.11 [90/130816] via 192.168.1.2, 02:30:29, GigabitEthernet2 >> Route to be exchange to the VRF A routing table. 

LEAK#show ip route vrf A

Routing Table: A
Codes: L - local, 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, m - OMP
n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA
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
H - NHRP, G - NHRP registered, g - NHRP registration summary
o - ODR, P - periodic downloaded static route, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/30 is directly connected, GigabitEthernet1
L 10.0.0.1/32 is directly connected, GigabitEthernet1
172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [200/0] via 10.0.0.2, 01:47:58 >> Route to be exchange to the global routing table.

Configureren

Voltooi de procedures om het lek tussen de twee routeringstabellen te maken:

Step 1.
Create route-maps to filter the routes to be injected in both routing tables.

LEAK(config)#Route-map VRF_TO_EIGRP
LEAK(config-route-map)#match ip address prefix-list VRF_TO_EIGRP
LEAK(config-route-map)#exit
!
Prefix-list created to match the host that is attached to the previous route-map configured.
!
ip prefix-list VRF_TO_EIGRP permit 172.16.10.10/32

or

LEAK(config)#Route-map VRF_TO_EIGRP
LEAK(config-route-map)# match ip address 10 
LEAK(config-route-map)#exit
!
ACL created to match the host that is attached to the previous route-map.
!
LEAK#show ip access-lists 10 
10 permit 172.16.10.10

LEAK(config)#Route-map EIGRP_TO_VRF
LEAK(config-route-map)#match ip address prefix-list EIGRP_TO_VRF 
LEAK(config-route-map)#exit
LEAK(config)#
!
Prefix-list created to match the host that is attached to the previous route-map configured.
!
ip  prefix-list EIGRP_TO_VRF  permit 192.168.11.11/32

or

LEAK(config)#Route-map EIGRP_TO_VRF
LEAK(config-route-map)#match ip address 20 
LEAK(config-route-map)#exit
LEAK(config)#
!
ACL created to match the host that is attached to the previous route-map.
!
LEAK#show ip access-list 20
10 permit 192.168.11.11


Step 2.
Define the import/export maps and add the route-map names.

LEAK(config)#vrf definition A 
LEAK(config-vrf)#address-family ipv4 
LEAK(config-vrf-af)#import ipv4 unicast map EIGRP_TO_VRF >> Import the global routing table routes at the VRF routing table.
LEAK(config-vrf-af)#export ipv4 unicast map VRF_TO_EIGRP >> Export the VRF routes to the Global Routing Table.
LEAK(config-vrf-af)#end

Step 3. 
Proceed with the dual redistribution.

Redistribute EIGRP 

LEAK(config)#router bgp 1
LEAK(config-router)#redistribute eigrp 1 
LEAK(config-router)#end

Redistribution BGP

LEAK(config)#router eigrp 1
LEAK(config-router)#redistribute bgp 1 metric 100 1 255 1 1500 
LEAK(config-router)#end

Verifiëren

Routing table from VRF A 

LEAK#show ip route vrf A

Routing Table: A

< Snip for resume >

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/30 is directly connected, GigabitEthernet1
L 10.0.0.1/32 is directly connected, GigabitEthernet1
172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [200/0] via 10.0.0.2, 00:58:53
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
B 192.168.1.0/24 is directly connected, 00:01:00, GigabitEthernet2
L 192.168.1.1/32 is directly connected, GigabitEthernet2
192.168.11.0/32 is subnetted, 1 subnets 
B 192.168.11.11 [20/130816] via 192.168.1.2, 00:01:00, GigabitEthernet2 >> Route from global routing table at VRF A routing table.

Global Routing Table (EIGRP)

LEAK#show ip route 

< snip for resume >

Gateway of last resort is not set

172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [200/0] via 10.0.0.2 (A), 00:04:47  >> Route from VRF A at global routing table.
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, GigabitEthernet2
L 192.168.1.1/32 is directly connected, GigabitEthernet2
192.168.11.0/32 is subnetted, 1 subnets
D 192.168.11.11 [90/130816] via 192.168.1.2, 01:03:35, GigabitEthernet2
LEAK#

Scenario 2 - VRF-lekken tussen VRF A en VRF B

Scenario 2 beschrijft het lek tussen twee verschillende VRF’s.

Netwerkdiagram

In dit document wordt deze netwerkconfiguratie gebruikt:

Afbeelding 2. Route Lekkende Topologie voor Scenario 2

Router LEAK heeft een BGP-buurt met een buurman in VRF A en een OSPF-buurman in de VRF B. Apparaat 192.168.11.11 moet verbinding maken met apparaat 172.16.10.10 in het hele netwerk.

Router LEAK kan niet routeren tussen de twee omdat de routes in verschillende VRF's zijn. Deze routeringstabellen geven de huidige routes per VRF weer en geven aan welke routes tussen de VRF A en VRF B moeten worden gelekt.

LEAK Routing Table:

LEAK#show ip route vrf A

Routing Table: A
Codes: L - local, 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, m - OMP
n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA
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
H - NHRP, G - NHRP registered, g - NHRP registration summary
o - ODR, P - periodic downloaded static route, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/30 is directly connected, Ethernet0/0
L 10.0.0.2/32 is directly connected, Ethernet0/0
172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [200/0] via 10.0.0.1, 00:03:08 >> Route to be exchange to routing table VRF B.  

LEAK#show ip route vrf B

Routing Table: B
Codes: L - local, 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, m - OMP
n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA
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
H - NHRP, G - NHRP registered, g - NHRP registration summary
o - ODR, P - periodic downloaded static route, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, Ethernet0/1
L 192.168.1.2/32 is directly connected, Ethernet0/1
192.168.11.0/32 is subnetted, 1 subnets
O 192.168.11.11 [110/11] via 192.168.1.1, 00:58:45, Ethernet0/1 >> Route to be exchange to routing table VRF A.

Configureren

Voltooi deze procedures om het lek tussen de twee routeringstabellen te maken:

Step 1.
Create route-maps to filter the routes to be injected in both routing tables.

LEAK(config)#Route-map VRFA_TO_VRFB 
LEAK(config-route-map)#match ip address prefix-list VRFA_TO_VRFB 
LEAK(config-route-map)#exit
!
Prefix-list created to match the host and IP segment that is attached to the previous route-map configured.
!
ip prefix-list VRFA_TO_VRFB permit 172.16.10.10/32
ip prefix-list VRFA_TO_VRFB permit 10.0.0.0/30

or

LEAK(config)#Route-map VRFA_TO_VRFB 
LEAK(config-route-map)#match ip address 10 
LEAK(config-route-map)#exit
!
ACL created to match the host and IP segment that is attached to the previous route-map.
!
LEAK#show ip access-lists 10
10 permit 172.16.10.10
20 permit 10.0.0.0


LEAK(config)#Route-map VRFB_TO_VRFA 
LEAK(config-route-map)#match ip address prefix-list VRFB_TO_VRFA 
LEAK(config-route-map)#exit
!
Prefix-list created to match the host and IP segment that is attached to the previous route-map configured.
!
ip prefix-list VRFB_TO_VRFA permit 192.168.11.11/32
ip prefix-list VRFB_TO_VRFA permit 192.168.1.0/24

or

LEAK(config)#Route-map VRFB_TO_VRFA 
LEAK(config-route-map)#match ip address 20 
LEAK(config-route-map)#exit
!
ACL created to match the host and IP segment that is attached to the previous route-map configured.
!
LEAK#show ip access-lists 20 
10 permit 192.168.11.11
20 permit 192.168.1.0

Step 2.
At the VRFs configure the import/export map, use the route-map names to leak the routes.

LEAK(config)#vrf definition A 
LEAK(config-vrf)#address-family ipv4 
LEAK(config-vrf-af)#export map VRFA_TO_VRFB 
LEAK(config-vrf-af)#import map VRFB_TO_VRFA 


LEAK(config)#vrf definition B 
LEAK(config-vrf)#address-family ipv4 
LEAK(config-vrf-af)#export map VRFB_TO_VRFA 
LEAK(config-vrf-af)#import map VRFA_TO_VRFB 

Step 3.
Add the route-target to import and export the route distinguisher from both VRFs.

! --- Current configuration for VRF A

vrf definition A
rd 1:2
!
address-family ipv4
route-target export 1:2 
route-target import 1:1 
exit-address-family

! --- Current configuration from VRF B

vrf definition B
rd 2:2
!
address-family ipv4
exit-address-family

! --- Import the routes from VRF  B into VRF A

LEAK(config)#vrf definition A 
LEAK(config-vrf)#address-family ipv4 
LEAK(config-vrf-af)#route-target import 2:2  

! --- Import routes from VRF A to VRF B and export routes from VRF B

LEAK(config-vrf-af)#vrf definition B 
LEAK(config-vrf)#address-family ipv4 
LEAK(config-vrf-af)#route-target import 1:2 
LEAK(config-vrf-af)#route-target export 2:2 

Verifiëren

Check the Routing Tables 

VRF A Routing Table 

LEAK#show ip route vrf A

Routing Table: A

< Snip for resume >

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/30 is directly connected, Ethernet0/0
L 10.0.0.2/32 is directly connected, Ethernet0/0
172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [200/0] via 10.0.0.1, 00:07:20
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
B 192.168.1.0/24 is directly connected, 00:00:10, Ethernet0/1
L 192.168.1.2/32 is directly connected, Ethernet0/1
192.168.11.0/32 is subnetted, 1 subnets
B 192.168.11.11 [20/11] via 192.168.1.1 (B), 00:00:10, Ethernet0/1 >> Route from VRF B routing table at VRF A. 

VRF B Routing Table 

LEAK#show ip route vrf B
Routing Table: B

< Snip for resume >

10.0.0.0/30 is subnetted, 1 subnets
B 10.0.0.0 [200/0] via 10.0.0.1 (A), 00:00:15
172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [200/0] via 10.0.0.1 (A), 00:00:15 >> Route from VRF A routing table at VRF B. 
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, Ethernet0/1
L 192.168.1.2/32 is directly connected, Ethernet0/1
192.168.11.0/32 is subnetted, 1 subnets
O 192.168.11.11 [110/11] via 192.168.1.1, 01:05:12, Ethernet0/1 

Scenario 3 - VRF-lekken tussen OSPF (VRF) en EIGRP (wereldwijd) met BGP (optioneel)

Scenario 3 beschrijft het routelek tussen twee IGP’s (VRF B en Global VRF).

Netwerkdiagram

Het netwerk in dit document is als volgt opgebouwd:

Afbeelding 3. Route Lekkende Topologie voor Scenario 3

Router LEAK heeft een OSPF-buurt voor een buur in VRF B en een EIGRP-buur in de wereldwijde VRF. Apparaat 172.16.10.10 moet verbinding kunnen maken met apparaat 192.168.11.11 in het hele netwerk.

Router LEAK kan deze twee hosts niet verbinden. Deze routeringstabellen tonen de huidige routes per VRF en geven aan welke routes moeten worden gelekt tussen de VRF B en Global VRF.

LEAK Routing Table:

LEAK#show ip route 
Codes: L - local, 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, m - OMP
n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA
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
H - NHRP, G - NHRP registered, g - NHRP registration summary
o - ODR, P - periodic downloaded static route, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, Ethernet0/1
L 192.168.1.1/32 is directly connected, Ethernet0/1
192.168.11.0/32 is subnetted, 1 subnets
D 192.168.11.11 [90/1024640] via 192.168.1.2, 01:08:38, Ethernet0/1 >> Route to be exchange from global routing table at VRF B routing table.

LEAK#show ip route vrf B

Routing Table: B
Codes: L - local, 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, m - OMP
n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA
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
H - NHRP, G - NHRP registered, g - NHRP registration summary
o - ODR, P - periodic downloaded static route, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/30 is directly connected, Ethernet0/0
L 10.0.0.2/32 is directly connected, Ethernet0/0
172.16.0.0/32 is subnetted, 1 subnets
O 172.16.10.10 [110/11] via 10.0.0.1, 01:43:45, Ethernet0/0 >> Route to be exchange from routing table VRF B at global routing table.

Configureren

Voltooi deze procedures om het lek tussen de twee routeringstabellen te maken:

Step 1.
Create route-maps for import and export to be injected in both routing tables.

LEAK(config)#Route-map OSPF_TO_EIGRP
LEAK(config-route-map)#match ip address prefix-list OSPF_TO_EIGRP 
LEAK(config-route-map)#exit
!
Prefix-list created to match the host that is attached to the previous route-map configured.
!
ip prefix-list OSPF_TO_EIGRP permit 172.16.10.10/32
ip prefix-list OSPF_TO_EIGRP permit 10.0.0.0/30

or

LEAK(config)#Route-map OSPF_TO_EIGRP 
LEAK(config-route-map)#match ip address 10 
LEAK(config-route-map)#exit
!
ACL created to match the host that is attached to the previous route-map.
!
LEAK#show ip access-lists 10 
10 permit 172.16.10.10
20 permit 10.0.0.0

LEAK(config)#Route-map EIGRP_TO_OSPF 
LEAK(config-route-map)#match ip address prefix-list EIGRP_TO_OSPF 
LEAK(config-route-map)#exit
!
Prefix-list created to match the host that is attached to the previous route-map configured.
!
ip prefix-list EIGRP_TO_OSPF permit 192.168.11.11/32
ip prefix-list EIGRP_TO_OSPF permit 192.168.1.0/24

or

LEAK(config)#Route-map EIGRP_TO_OSPF 
LEAK(config-route-map)#match ip address 20
LEAK(config-route-map)#exit
!
ACL created to match the host that is attached to the previous route-map.
!
LEAK#show ip access-lists 20
10 permit 192.168.11.11
20 permit 192.168.1.0/24

Step 2.
Add the import/export maps in order to match the route-map names.

Current configuration
!
vrf definition B
rd 1:2 
!
address-family ipv4 
exit-address-family
!
!
LEAK(config-vrf)#vrf definition B 
LEAK(config-vrf)#address-family ipv4 
LEAK(config-vrf-af)#import ipv4 unicast map EIGRP_TO_OSPF
LEAK(config-vrf-af)#export ipv4 unicast map OSPF_TO_EIGRP

Step 3.
To perform the leak is necessary to create a BGP process, in order to redistribute 
the IGPs protocols.

router bgp 1
bgp log-neighbor-changes
! 
address-family ipv4 vrf B >> Include the address-family to inject VRF B routing table (OSPF)
!
exit-address-family

Opmerking: zorg ervoor dat de VRF een routeverdeler heeft geconfigureerd om de fout te voorkomen:
"%vrf B does not have rd configured, configure "rd" before configuring import route-map"

Step 4.
Create a Dual Redistribution.

IGPs redistribution.

LEAK(config-router)#router bgp 1 
LEAK(config-router)#redistribute eigrp 1
!
LEAK(config-router)#address-family ipv4 vrf B 
LEAK(config-router-af)#redistribute ospf 1 match internal external 1 external 2 
LEAK(config-router-af)#end

BGP Redistribution

LEAK(config)#router ospf 1 vrf B 
LEAK(config-router)#redistribute bgp 1
!
LEAK(config-router)#router eigrp TAC
LEAK(config-router)# 
LEAK(config-router)# address-family ipv4 unicast autonomous-system 1
LEAK(config-router-af)# 
LEAK(config-router-af)# topology base
LEAK(config-router-af-topology)#redistribute bgp 1 metric 100 1 255 1 1500

Verifiëren

Controleer de routeringstabellen

LEAK#show ip route

< Snip for resume >

172.16.0.0/32 is subnetted, 1 subnets
B 172.16.10.10 [20/11] via 10.0.0.1, 00:14:48, Ethernet0/0 >> Route from VRF B routing table at global routing table ( EIGRP ). 
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, Ethernet0/1
L 192.168.1.1/32 is directly connected, Ethernet0/1
192.168.11.0/32 is subnetted, 1 subnets
D 192.168.11.11 [90/1024640] via 192.168.1.2, 02:16:51, Ethernet0/1

LEAK#show ip route vrf B
Routing Table: B

< Snip for resume >

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/30 is directly connected, Ethernet0/0
L 10.0.0.2/32 is directly connected, Ethernet0/0
172.16.0.0/32 is subnetted, 1 subnets
O 172.16.10.10 [110/11] via 10.0.0.1, 00:34:25, Ethernet0/0
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
B 192.168.1.0/24 is directly connected, 00:08:51, Ethernet0/1
L 192.168.1.1/32 is directly connected, Ethernet0/1
192.168.11.0/32 is subnetted, 1 subnets
B 192.168.11.11 [20/1024640] via 192.168.1.2, 00:08:51, Ethernet0/1 >> Route from global routing table ( EIGRP ) at VRF B routing table.

Scenario 4 - VRF Default Route Leak van OSPF naar BGP

Scenario 4 geeft een voorbeeld van VRF standaard route lekken van OSPF naar BGP.

Netwerkdiagram

Het netwerkdiagram zoals te zien in afbeelding 4 toont de laag 3-topologie waar standaard routelekans nodig is.

Afbeelding 4. Route lekkende topologie voor scenario 4

Het OSPF- en BGP-proces worden uitgevoerd in verschillende VRF op Router LEAK. De standaardroute is aanwezig in Router OSPF. Router LEAK heeft een BGP-wijk in VRF A met Router BGP en een OSPF-wijk in VRF B met Router OSPF. 

Standaard routelek van OSPF naar BGP op Router LEAK wordt hieronder weergegeven.

Configureren

Step 1
Check if a static default route is present in Router OSPF.

OSPF#sh ip route

<output snipped>

Gateway of last resort is 192.168.10.2 to network 0.0.0.0 

S* 0.0.0.0/0 [1/0] via 192.168.10.2   >>> default route is present in the routing table.
C 192.168.0.0/24 is directly connected, GigabitEthernet2
L 192.168.0.2/32 is directly connected, GigabitEthernet2
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.10.0/24 is directly connected, GigabitEthernet1
L 192.168.10.1/32 is directly connected, GigabitEthernet1


Step 2
From the OSPF router, the default route needs to be advertised in OSPF to Router LEAK.

Use the command "default-information originate" on Router OSPF under OSPF process:( if there is static route in the OSPF router, routing table as verified in Step 1)


OSPF(config)#router ospf 1
OSPF(config-router)#default-information originate


If there is no static route in the Router OSPF routing table then we can generate and advertise a default route to the OSPF neighbour.


OSPF(config)#router ospf 1
OSPF(config-router)#default-information originate always

This forces the router to advertise a default route even if it doesn't have one in its routing table.


Step 3.1
Verify on Router LEAK, if an external OE2 route is installed in the VRF B routing table:

LEAK#sh ip route VRF B

Routing Table: B

<output snipped>

Gateway of last resort is 192.168.0.2 to network 0.0.0.0

O*E2 0.0.0.0/0 [110/1] via 192.168.0.2, 00:05:51, GigabitEthernet2 >>> OE2 route is installed in the VRF B routing table (This needs to be leaked in BGP)
192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.0.0/24 is directly connected, GigabitEthernet2
L 192.168.0.1/32 is directly connected, GigabitEthernet2

Step 3.2
Configure a prefix-list on Router LEAK

LEAK# conf t
LEAK(config)# ip prefix-list OSPF_TO_BGP seq 5 permit 0.0.0.0/0

Configure a route-map to match the prefix-list.

LEAK(config-route-map)#route-map OSPF_TO_BGP permit 10
LEAK(config-route-map)# match ip address prefix-list OSPF_TO_BGP
LEAK(config-route-map)#exit

Step 3.3
Verify on Router LEAK, that required VRFs , Route Distinguishers (RD) an Route Targets (RT) are configured.

LEAK(config)#vrf definition A
LEAK(config-vrf)#rd 1:1
LEAK(config-vrf)#address-family ipv4
LEAK(config-vrf-af)#route-target import 6500:1
LEAK(config-vrf-af)#exit-address-family
LEAK(config-vrf-af)#end
LEAK#

LEAK(config)#vrf definition B
LEAK(config-vrf)#rd 2:2
LEAK(config-vrf)#address-family ipv4
LEAK(config-vrf-af)#route-target export 6500:1
LEAK(config-vrf-af)#exit-address-family
LEAK(config-vrf-af)#end
LEAK#

Step 3.4
Configure import map in VRF A.

LEAK#conf t
LEAK(config)#vrf definition A
LEAK(config-vrf)#address-family ipv4
LEAK(config-vrf-af)#import map OSPF_TO_BGP
LEAK(config-vrf-af)#end
LEAK#


Step 3.5 
Create an address family VRF B in the BGP configuration and advertise “0.0.0.0”

LEAK#sh run | sec bgp
redistribute bgp 6501
router bgp 6501
bgp router-id 10.0.0.1
bgp log-neighbor-changes
!
address-family ipv4 vrf A
neighbor 10.0.0.2 remote-as 6500
neighbor 10.0.0.2 activate
exit-address-family
!
address-family ipv4 vrf B
network 0.0.0.0
exit-address-family

Opmerking: Het maken van een adresfamilie met VRF in de BGP werkt zelfs zonder een buurman te activeren. Alleen het paaien van het BGP-proces is nodig om de routes tussen de VRF te lekken.

Verifiëren

Verify the default route available in BGP.

LEAK#sh ip route vrf A

Routing Table: A

<output snipped>

Gateway of last resort is 192.168.0.2 to network 0.0.0.0

B* 0.0.0.0/0 [20/1] via 192.168.0.2 (B), 00:15:36, GigabitEthernet2 >>> Default route of VRF B routing table in VRF A routing table.
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/24 is directly connected, GigabitEthernet1
L 10.0.0.1/32 is directly connected, GigabitEthernet1

Aanvullende bronnen