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Author Topic: OSPF Balancing through two ISP  (Read 594 times)

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Offline luismaportillo

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  • Posts: 3
OSPF Balancing through two ISP
« on: February 10, 2017, 11:27:30 AM »
Dear Mr McNamara,  Hope youre ok.

I´m  writing because  i´m  litle bit confusing about  OSPF Balancing, the escenario that i have is the following:

I have a Branch Office   which has conection  to the HQ through two differents ISP , in that office  i just have one router  which receive the two ISP Links ,  also in the HQ  i just have a Main Router  for the Links.

In the office´s Router   i have made an OSPF configuration  to allow conectivity to the HQ,  below the OSPF detailed:


interface Tunnel0
 ip address 10.10.8.2 255.255.255.252
 ip tcp adjust-mss 1400
 ip ospf cost 10
 keepalive 15 3
 tunnel source GigabitEthernet0/0
 tunnel destination 10.8.19.130


interface GigabitEthernet0/0
 description ***WAN ISP_1***
 bandwidth 5000
 ip address 172.31.8.2 255.255.255.252
 ip flow ingress
 ip flow egress
 no ip route-cache cef
 ip tcp adjust-mss 1400
 ip ospf priority 250
 ip ospf cost 10
 load-interval 60
 duplex auto
 speed auto
 service-policy output WANQoS


interface GigabitEthernet0/0/0
 description ***WAN ISP_2***
 switchport access vlan 2467
 bandwidth 5000
 no ip address
 load-interval 60
 duplex full
 speed 100

interface Vlan2467
 bandwidth 5000
 ip address 172.16.8.2 255.255.255.252
 ip nbar protocol-discovery ipv4
 ip flow ingress
 ip flow egress
 ip ospf priority 150
 ip ospf cost 15
 load-interval 60
 service-policy output WANQoS-Telecarrier


router ospf 8
 passive-interface GigabitEthernet0/1
 network 10.10.8.0 0.0.0.3 area 0
 network 172.16.8.0 0.0.0.3 area 0
 network 172.31.8.0 0.0.0.3 area 0
 network 192.168.8.0 0.0.0.255 area 0


Right now the Office´s Router has two adjacencies with the same router on HQ,

R2901_LosPueblos#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
10.159.0.1      150   FULL/BDR        00:00:34    172.16.8.1      Vlan2467
10.159.0.1        0   FULL/  -        00:00:35    10.10.8.1       Tunnel0
R2901_LosPueblos#



The Question is  if i  need to send some traffic through the ISP_1  and other through ISP_2  who could i fix that, because rigth now the whole traffic is  leaving from the office through ISP_2, i dont undestarnd why,  if ISP_2 has a highest cost than ISP1,  also i have noticed that the  the OSPF network type for ISP_1 is Point to Point and for ISP_2 is Broadcast,  that  cause a faster convergencie time for ISP1 but i dont know if that influency on the network routing.


Will appreciate if you can help me with my doubt.


Best Regards.