load sharing between two ISP's

[BGP65111]

Dears,

i have two different ISP's connected to two different ISR routers and connected to Internet Access Switch(3850) then connected to my internal network.

my questions is there any protocol i can configure either on access switch or routers to do load sharing for outgoing traffic to the internet ?

in different word a protocol will do  sense for my two up links to internet and make division to the outgoing traffic .

[Jose Lucas]

You need to configure a routemap with policy routing to separate outgoing traffic and based on the destination port to take it out through your second gateway to the internet, missing data to give you a more concrete answer.

[Moses Fernandes]

You may consider First Hop Redundancy Protocol (FHRP) GLBP...
(GLBP OverView) https://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html.

(GLBP allows packet load sharing between a group of redundant routers)
Other options...
(VRRP OverView)https://www.cisco.com/c/en_intl/support/docs/security/vpn-3000-series-concentrators/7210-vrrp.html
(HSRP OverView ) https://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9234-hsrpguidetoc.html
This should do the trick (easy to configure).

Regards,
Moses.

[Joseph W. Doherty]

Yes, there are several ways to accomplish that. Which is best depends on you topology, for both L2 and L3, and also the nature of your traffic.

Most methods split L2 or L3 "statically", i.e. they send half the traffic flows on one path and half the traffic flows on the other.

Some of these methods, can be tweaked, manually, to proportionally send more flows on one path vs. the other.

The trouble with the above, if generally divides flows not knowing how bandwidth intense any flow is.

Cisco has a technology, PfR, that can also do dynamic load balancing. This technology can do more. For example, given your two ISPs, it can actually also determine which path provides the best performance to destinations and direct flows accordingly.

[Richard Burts]

The question from the original poster is quite complex - how to load share when you have two ISP. There are multiple options but before we consider those options there are some things that we need to know from the original poster:

1) are you running a dynamic routing protocol with the ISPs or is your Internet access based on static routing?

2) do you have your own IP address space that is assigned to you or are you using address space from your providers?

3) how big is your address space?

There have been suggestions about using Policy Based Routing and about using PfR. I would suggest another alternative which is to have one ISP advertise a set of addresses to you and to have the second ISP to advertise a different set of addresses which would result in load sharing.

I will observe that all of these suggestions deal with how to share outbound traffic. There is also a question of how to share inbound traffic. This is actually more complex than sharing outbound traffic and the alternatives for this mostly depend on things we do not know yet (do you have provider independent address space, how big is your address space, do you do dynamic routing with providers).

HTH

Rick