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saimbt
Beginner

remove-private-AS

Please find attached scenario and let me know whether this will work.

I have a single router and 2 ISP's from the same provider. In the attached scenario, can i achieve auto-redundancy and inbound and outbound load-sharing.

-Sai.

10 REPLIES 10
s.arunkumar
Participant

If u want load sharing u need to give "maximum-path 2" command.

Even a better configuration i suggest is creat a loopback address on both and form the ebgp session across it(use update source and ebgp-multihop command).Give two static route entry for on each router for the loopback address with nexthop as the other two interfaces IP,also give maximum-path cmd at both end.

try out this

arun

going a bit further.

1) Can i used local preference on R1 for outbound load sharing.

2) Can I used MED for incoming load sharing.

Will the partial config sent in the vsd work?

Danilo Dy
Collaborator

Hi,

Can you post your diagram in JPG format? Not all NetPro have privilege to use Visio everywhere/anywhere/anytime - and license.

If both links terminate in the same router (your router and ISP router). Use Arun's recommendation of using loopback (both routers), route statically the loopback IP Address, configure eBGP multihop of 2 using loopback IP Address, configure BGP multipath 2.

Check this link http://www.cisco.com/warp/public/459/40.html

Regards,

Dandy

Hi Dandy,

here is the diagram in JPG format.

Hi,

Arun's solution is really good if u want single neighbor relationship.

You can do load sharing for inbound traffic with MED and as-path as well.

Outbound traffic load sharing can be done by many ways.

Here is config for inbound traffice load sharing using med.

router bgp X

neigh 1.1.1.1 route-map MED out

neigh 2.2.2.2 route-map MED1 out

!

route-map MED permit 10

match ip address 10

set med 100

!

route-map MED permit 20

set med 200

!

route-map MED1 permit 10

match ip address 10

set med 200

!

route-map MED permit 20

set med 100

!

access-list 10 x.x.x.x x.x.x.x

HTH.

Cheers,

Nikhil E.

Hi Gurus,

instead of using maximum-paths 2, if i set the local preference on both the links equal, can I achieve load sharing?

-sai.

Hi sai,

Now what nikhil said is correct for incoming traffic .

Yes u can adjust local preference for outgoing traffic without using maximum-path.

Say you have x and y network at remote end.

If u want to use link 1 for traffic going to X and link 2 for traffic towards Y you can do so by making the local prefernce of X more for updates are coming from link 1 than 2 and similarly for Y at link 2.

Hence traffic towards X would use a link 1 and Y link 2,hence the load sharing u desire.. ;)

arun

if i am learning default routes from the service provider and for the ISP's AS, if i set a route map and set the local preference as 100, will I achieve load sharing?

-Sai.

hi sai,

Since you dont have a specific routes towards destination (ie,only default route)i think working out with local prefernce will not help.

In this case i think the method i suggested on my first post is better..

lets hear for any comments 4rm experts.. ;)

arun

I guessed it as much. If there is a tie on the local pref attribute, BGP would consider the next attribute and select the best path.

-Sai.