# CEF Polarization **URL:** https://forum.networklessons.com/t/cef-polarization/1850 **Category:** Lessons Discussion **Created:** [June 26, 2017, 1:34pm UTC](https://forum.networklessons.com/t/cef-polarization/1850 "2017-06-26T13:34:43Z") **Posts on this page:** 1 **Showing post:** 3
### Author: ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar) #### Post date: [July 6, 2017, 6:28pm UTC](https://forum.networklessons.com/t/cef-polarization/1850/3 "2017-07-06T18:28:38Z")
Hi Zaman, What I mean by this is that for a single flow, the router always selects the same interface no matter the hash algorithm you use. The advantage of using a hash algorithm that uses more parameters is that you will have better load balancing since different flows will use different interfaces. For example, if you use a hashing algorithm that only includes source and destination IP address then it’s likely that the following flows will all get the same result and use the same outbound interface. Here’s a quick example, let’s say we have these flows: 192.168.1.1 \> 192.168.2.2 192.168.1.2 \> 192.168.2.2 192.168.1.3 \> 192.168.2.2 192.168.1.4 \> 192.168.2.2 192.168.1.5 \> 192.168.2.2 192.168.1.7 \> 192.168.2.2 192.168.1.9 \> 192.168.2.2 If we had two outgoing interfaces, it would be nice to see 4 flows on each interface so that we have some load sharing. However in reality, it’s likely that the flows get mapped like this: INTERFACE 1: 192.168.1.1 \> 192.168.2.2 192.168.1.3 \> 192.168.2.2 192.168.1.5 \> 192.168.2.2 192.168.1.7 \> 192.168.2.2 192.168.1.9 \> 192.168.2.2 INTERFACE 2: 192.168.1.2 \> 192.168.2.2 192.168.1.4 \> 192.168.2.2 In this case, interface 1 gets the most flows. By using a hashing algorithm with more parameters, the chance that each interface gets 50% of the flows increases. Still, this doesn’t consider how much traffic each flow has so it’s more like “flow” balancing than load balancing 🙂 Per packet load balancing does evenly share the load, even though the packets belong to the same flow yes. --- _[View the full topic](https://forum.networklessons.com/t/cef-polarization/1850)._