How to do Failover??

[vinayak]

Hello Everyone,

Currently i am having one router to which we are having 3 ISP connections. each having diffrent WAN ips.

Means Office A --- connected to ISP1

Office B ---- Connected to ISP2

Office C --- connected to ISP3

Internet Links ISP 1 & ISP 2 are from same service provider (Lets Say ABC)

& ISP 3  is from Diffrent Service Provider (Say XYZ)

my question is if ISP 1 & ISP 2 gose down at a time Then Can i run the whole network of 3 Officies (A,B & C) on single ISP (i.e ISP 3) ???

is this possible ???

[boopathi.manickam]

You have to apply the HSRP configuration on R1.

ISP1 & ISP 2 --- One Virtual IP address - HSRP Group1

ISP2 & ISP 3 --- Other Virtual IP address- HSRP Group1

R1:

Router 1 :

Serial 0:

standby 1 ip 171.16.6.100----Virtual IP for ISP 1 & ISP2

standby 1 priority 105

standby 1 preempt delay minimum 10

standby 1 track Serial0

Serial 1

standby 1 ip 171.16.6.100----Virtual IP for ISP 1 & ISP2

standby 1 priority 100

standby 1 preempt delay minimum 10

standby 1 track Serial1

Serial 3:

standby 1 ip 171.16.6.100----Virtual IP for ISP 2 & ISP3

standby 1 priority 95

standby 1 preempt delay minimum 10

standby 1 track Serial3

[vinayak]

Hello,

If i done the above config. & my ISP 1 & ISP 2 gose down at a time. Then can i use ISP 3 to run my network of 3 Offices ???

[boopathi.manickam]

This is for example. Before implementing the HSRP config  you have to do the testing using GNS3 simulator or Boson

[Mahesh Gohil]

Hi vinayak,

There is one more option of redundancy via. BGP. I mean if you are running BGP with your ISP then below is the solution and

it is already tested. This is like is ISP1 goes down then ISP2 will take over and if both goes down ISP3 will take over all traffic

1- Please put local preference of 200 for ISP1 for outgoing traffic and leave path prepend as it is

   route-map LP permit 10

   set local-preference 200

   router bgp xxxx

   neighbor x.x.x.x route-map LP in

2- Put local preference of 150 for ISP2 and set as-path prepending with 2

   route-map LP permit 10

   set local-preference 150

  route-map AS-PATH permit 10

   set as-path-prepend xxxx xxxx (xxxx is your AS number)

   router bgp xxxx

   neighbor x.x.x.x route-map LP in

   neighbor x.x.x.x route-map AS-PATH out

3- Leave local-preference to default and set as-path-prepend to 3

  route-map AS-PATH permit 10

   set as-path-prepend xxxx xxxx xxxx (xxxx is your AS number)

and make sure you advertise your IP to all the ISP. (This is possible if you have your own IP taken from routing registry because IP given by ISP1 will not be allowed by ISP2..what I assume)

Please feel free to put any further query

Regards

Mahesh