Optimized distributed routing for stretched data center models through updating route advertisements based on changes to address resolution protocol(ARP)table

摘要

In a subnet of a network, port members of an Internet Protocol (IP) interface or Virtual Local Area Network (VLAN) are distinguished into Access Interfaces which only lead to hosts on the subnet and Trunk Interfaces which lead to other redundant routers on the subnet. A network route for the subnet is always advertised. A separate host route corresponding to an Internet Protocol (IP) address of each Address Resolution Protocol (ARP) table record that points to an Access Interface is also advertised. Another router trying to forward traffic to the host will find the host route first, and since this is based on whichever router is closest to the host, it eliminates the potential for sub optimal routing behaviour. Route advertisements are changed for a host in the subnet for tracked Access Interfaces. For example, when an ARP record ages out or changes to point to a Trunk Interface, the corresponding host route advertisement is withdrawn.