Load balancing with static route + IP SLA - is this right ?

[SJ K]

Hi all,

My router is connected to L2 switch and then to 2 gateway/CE mpls router.

As shown below

So I have 2 gateway (10.10.10.2, 10.10.10.3)  for my overseas office network  -> 192.168.30.0/24.

As I am inexperience, I want the setup to be as simple and straightforward as possible.

Can I do the following

Load Balancing

On the my "Office Router",  i have created 2 static route with same AD

ip route 192.168.30.0 255.255.255.0 10.10.10.2 track 1

ip route 192.168.30.0 255.255.255.0 10.10.10.3 track 2

ip cef

ip load-sharing per-packet (on each individual exit interface)

-- Assuming both links are of equal speed and latency etc..

IP SLA

Setup IP SLA that pings 10.10.10.2 or the WAN interface of the PE MPLS router

Setup IP SLA that pings 10.10.10.3 or the WAN interface of the PE MPLS router

======================

So that when both links are up, I will load balance per packet via the 2 links (assuming we can accept out-of-order packets) - for load-balance

and

Use IPSLA to detect if the link is dead or too slow and let the traffic flow through another route  -- for high availability

============================

q1) Is the above setup sound ?

q2) can load balancing occur among static route with equal AD/metric ?

Hope to hear more advises from gurus here.

Thanks.
Regards,
Noob

[Carlos Villagran · Accepted solution]

Hi!

The setup is correct, however, there is no point for the track object to be pinging the private interfaces, please track the WAN interface availability.

Also, take in mind that both link better be equal because if some delay happen in any of them you could start experiencing serious delay.

Hope it helps, let me know of any other concern. Best regards!

JC

[Mark Malone · Accepted solution]

Ye I agree with Carlos looks good but always track upstream route when you can in ISP

Also when you do per-packet you need to be aware packets can come out of order which can effect critically sensitive apps , re-ordering like that can effect TCP traffic and likes of voice traffic

TCP stack can try to resolve these out of order but it doesn't always work in reality

Another option if your connecting to MPLS network you can get BGP off provider as you can do great load balancing and manipulation of routes in multi homed networks , if that's possible

[SJ K]

Thanks Carlos and Mark for the wonderful reply.

Yeap. I realize i did have VOIP traffic across the MPLS link and thus, i have turn off  packet load balancing :X

I have also posted some related questions with regards to load balancing using ip cef at ->

https://supportforums.cisco.com/discussion/13016431/understanding-show-ip-route-asterix-and-load-balancing

Greatly appreciate if you have the time to take alook.

Hope to hear from you guys!

Thank you!

Regards,

Noob