Fig:OSPF Virtual-Link Topology
OSPF Virtual link configuration for mikrotik router video
R1 Configuration:
[admin@Microtik-R1] > ip address add address=10.10.10.10/32 interface=loopback0
[admin@ Microtik -R1] > ip address add address=192.168.20.1/30 interface=ether1
[admin@ Microtik -R1] > ip address add address=192.168.10.1/24 interface=ether2
[admin@ Microtik -R1] > routing ospf instance set router-id=10.10.10.10 name=default disabled=no numbers=0
[admin@ Microtik -R1] > routing ospf area set backbone disabled=no area-id=0.0.0.0
[admin@ Microtik -R1] > routing ospf network add network=192.168.20.0/30 area=backbone
[admin@ Microtik -R1] > routing ospf network add network=192.168.10.0/24 area=backbone
R2 Configuration:
[admin@Microtik-R2] > ip address add address=9.9.9.9/32 interface=loopback0
[admin@Microtik-R2] > ip address add address=192.168.20.2/30 interface=ether1
[admin@Microtik-R2] > ip address add address=192.168.50.2/30 interface=ether2
[[admin@Microtik-R2] > routing ospf instance set router-id=9.9.9.9 name=default disabled=no numbers=0
[admin@Microtik-R2] > routing ospf area set backbone disabled=no area-id=0.0.0.0
[admin@Microtik-R2] > routing ospf area add name=Area1 area-id=0.0.0.1 disabled=no
[admin@Microtik-R2] > routing ospf network add network=192.168.20.0/30 area=backbone
[admin@Microtik-R2] > routing ospf network add network=192.168.50.0/30 area=Area1
[admin@Microtik-R2] > routing ospf virtual-link add neighbor-id=7.7.7.7 transit-area=Area1 disabled=no
R3 Configuration:
[admin@Microtik-R3] > ip address add address=7.7.7.7/32 interface=loopback0
[admin@Microtik-R3] > ip address add address=192.168.40.1/24 interface=ether2
[admin@Microtik-R3] > ip address add address=192.168.50.1/30 interface=ether1
[admin@Microtik-R3] > routing ospf instance set router-id=7.7.7.7 name=default disabled=no numbers=0
[admin@Microtik-R3] > routing ospf area set backbone disabled=no area-id=0.0.0.0
[admin@Microtik-R3] > routing ospf area add name=Area1 area-id=0.0.0.1 disabled=no
[admin@Microtik-R3] > routing ospf network add network=192.168.40.0/24 area=backbone
[admin@Microtik-R3] > routing ospf network add network=192.168.50.0/30 area=Area1
[admin@Microtik-R3] > routing ospf virtual-link add neighbor-id=9.9.9.9 transit-area=Area1 disabled=no
R1 Verification:
[admin@Mikrotik-R1] > routing ospf neighbor print
0 instance=default router-id=9.9.9.9 address=192.168.20.2 interface=ether1
priority=1 dr-address=192.168.20.1 backup-dr-address=192.168.20.2
state=”Full” state-changes=9 ls-retransmits=0 ls-requests=0 db-summaries=0
adjacency=22m17s
[admin@Mikrotik-R1] > routing ospf lsa print
AREA TYPE ID ORIGINATOR SEQUENCE-NUMBER AGE
backbone router 7.7.7.7 7.7.7.7 0x8000000E 1364
backbone router 9.9.9.9 9.9.9.9 0x80000015 1358
backbone router 10.10.10.10 10.10.10.10 0x8000000B 1368
backbone network 192.168.20.1 10.10.10.10 0x80000001 1368
backbone summary-n… 192.168.50.0 7.7.7.7 0x80000002 30
backbone summary-n… 192.168.50.0 9.9.9.9 0x80000004 1362
[admin@Mikrotik-R1] > routing ospf route print
# DST-ADDRESS STATE COST GATEWAY INTERFACE
0 192.168.10.0/24 intra-area 10 0.0.0.0 ether2
1 192.168.20.0/30 intra-area 10 0.0.0.0 ether1
2 192.168.40.0/24 intra-area 30 192.168.20.2 ether1
3 192.168.50.0/30 inter-area 20 192.168.20.2 ether1
[admin@Mikrotik-R1] > ip route print
Flags: X – disabled, A – active, D – dynamic, C – connect, S – static, r – rip, b – bgp, o – ospf, m – mme,
B – blackhole, U – unreachable, P – prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 ADC 10.10.10.10/32 10.10.10.10 loopback0 0
1 ADC 192.168.10.0/24 192.168.10.1 ether2 0
2 ADC 192.168.20.0/30 192.168.20.1 ether1 0
3 ADo 192.168.40.0/24 192.168.20.2 110
4 ADo 192.168.50.0/30 192.168.20.2 110
R2 Verification:
[admin@Mikrotik-R2] > routing ospf neighbor print
0 instance=default router-id=7.7.7.7 address=192.168.50.1
interface=virtual-link priority=1 dr-address=0.0.0.0
backup-dr-address=0.0.0.0 state=”Full” state-changes=4 ls-retransmits=0
ls-requests=0 db-summaries=0 adjacency=33m29s
1 instance=default router-id=10.10.10.10 address=192.168.20.1 interface=ether1
priority=1 dr-address=192.168.20.1 backup-dr-address=192.168.20.2
state=”Full” state-changes=6 ls-retransmits=0 ls-requests=0 db-summaries=0
adjacency=33m36s
2 instance=default router-id=7.7.7.7 address=192.168.50.1 interface=ether2
priority=1 dr-address=192.168.50.1 backup-dr-address=192.168.50.2
state=”Full” state-changes=5 ls-retransmits=0 ls-requests=0 db-summaries=0
adjacency=33m37s
[admin@Mikrotik-R2] > routing ospf lsa print
AREA TYPE ID ORIGINATOR SEQUENCE-NU… AGE
backbone router 7.7.7.7 7.7.7.7 0x8000000F 236
backbone router 9.9.9.9 9.9.9.9 0x80000016 230
backbone router 10.10.10.10 10.10.10.10 0x8000000C 248
backbone network 192.168.20.1 10.10.10.10 0x80000002 248
backbone summary-n… 192.168.50.0 7.7.7.7 0x80000002 706
backbone summary-n… 192.168.50.0 9.9.9.9 0x80000005 233
Area1 router 7.7.7.7 7.7.7.7 0x80000017 236
Area1 router 9.9.9.9 9.9.9.9 0x80000016 231
Area1 network 192.168.50.1 7.7.7.7 0x80000002 243
Area1 summary-n… 192.168.10.0 9.9.9.9 0x80000002 229
Area1 summary-n… 192.168.20.0 9.9.9.9 0x80000002 244
Area1 summary-n… 192.168.40.0 7.7.7.7 0x80000004 700
[admin@Mikrotik-R2] > routing ospf area-border-router print
# AREA ROUTERID STATE GATEWAY COST
0 backbone 7.7.7.7 intra-area 10
1 backbone 9.9.9.9 intra-area 0
2 Area1 7.7.7.7 intra-area 192.168.50.1 10
3 Area1 9.9.9.9 intra-area 0
[admin@Mikrotik-R2] > routing ospf route print
# DST-ADDRESS STATE COST GATEWAY INTERFACE
0 192.168.10.0/24 intra-area 20 192.168.20.1 ether1
1 192.168.20.0/30 intra-area 10 0.0.0.0 ether1
2 192.168.40.0/24 intra-area 20 192.168.50.1 ether2
3 192.168.50.0/30 intra-area 10 0.0.0.0 ether2
[admin@Mikrotik-R2] > ip route print
Flags: X – disabled, A – active, D – dynamic, C – connect, S – static, r – rip, b – bgp, o – ospf, m – mme,
B – blackhole, U – unreachable, P – prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 ADC 9.9.9.9/32 9.9.9.9 loopback0 0
1 ADo 192.168.10.0/24 192.168.20.1 110
2 ADC 192.168.20.0/30 192.168.20.2 ether1 0
3 ADo 192.168.40.0/24 192.168.50.1 110
4 ADC 192.168.50.0/30 192.168.50.2 ether2 0
R3 Verification :
[admin@MikroTik-3] > routing ospf neighbor print
0 instance=default router-id=9.9.9.9 address=192.168.50.2
interface=virtual-link priority=1 dr-address=0.0.0.0
backup-dr-address=0.0.0.0 state=”Full” state-changes=5 ls-retransmits=0
ls-requests=0 db-summaries=0 adjacency=47m12s
1 instance=default router-id=9.9.9.9 address=192.168.50.2 interface=ether1
priority=1 dr-address=192.168.50.1 backup-dr-address=192.168.50.2
state=”Full” state-changes=11 ls-retransmits=0 ls-requests=0
db-summaries=0 adjacency=47m19s
[admin@MikroTik-3] > routing ospf area-border-router print
# AREA ROUTERID STATE GATEWAY COST
0 backbone 7.7.7.7 intra-area 0
1 backbone 9.9.9.9 intra-area 10
2 Area1 7.7.7.7 intra-area 0
3 Area1 9.9.9.9 intra-area 192.168.50.2 10
[admin@MikroTik-3] > routing ospf route print
# DST-ADDRESS STATE COST GATEWAY INTERFACE
0 192.168.10.0/24 intra-area 30 192.168.50.2 ether1
1 192.168.20.0/30 intra-area 20 192.168.50.2 ether1
2 192.168.40.0/24 intra-area 10 0.0.0.0 ether2
3 192.168.50.0/30 intra-area 10 0.0.0.0 ether1
[admin@MikroTik-3] > ip route print
Flags: X – disabled, A – active, D – dynamic,
C – connect, S – static, r – rip, b – bgp, o – ospf, m – mme,
B – blackhole, U – unreachable, P – prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 ADC 7.7.7.7/32 7.7.7.7 loopback0 0
1 ADo 192.168.10.0/24 192.168.50.2 110
2 ADo 192.168.20.0/30 192.168.50.2 110
3 ADC 192.168.40.0/24 192.168.40.1 ether2 0
4 ADC 192.168.50.0/30 192.168.50.1 ether1 0