SharePoint Internal Load Balancing and Network load balancing

SharePoint Internal Load Balancing -  SharePoint internally manages service request load by its inbuilt "Application Discovery and Load Balancer Service". By default it works with Round Robin algorithm but can be customized as needed.

Network load balancing -
Also servers in the farm can be load balanced with pair of backup servers. In this case, if any of the server in SharePoint farm goes down the backup server will fill that up.

Came across few interesting links -

http://blogs.technet.com/b/meamcs/archive/2012/05/29/prepare-sharepoint-farm-part-3-prepare-nlb-for-sharepoint-web-front-end-wfe-servers.aspx

http://community.bamboosolutions.com/blogs/sharepoint-2013/archive/2014/01/10/network-load-balancing-for-sharepoint-2013-part-one-how-to-display-network-load-balancing-manager-in-windows-server-2008.aspx

https://www.martinhatch.com/2014/05/sharepoint-2013-reference-sheet-services-on-server.html