Using Layer 3 nPath routing, you can load balance traffic over a routed topology in your data center. In this deployment, the server sends its responses directly back to the client, even when the servers, and any intermediate routers, are on different networks. This routing method uses IP encapsulation to create a uni-directional outbound tunnel from the server pool to the server.
You can also override the encapsulation for a specified pool member, and either remove that pool member from any encapsulation or specify a different encapsulation protocol. The available encapsulation protocols are IPIP and GRE.
This illustration shows the path of a packet in a deployment that uses Layer 3 nPath routing through a tunnel.
The following illustration shows one example of an L3 nPath routing configuration in a network.
The following examples show the configuration code that supports the illustration.
Linux DSR server configuration:# modprobe ipip # ifconfig tunl0 10.102.4.10 netmask 255.255.255.0 up # ifconfig lo:0 10.102.3.202 netmask 255.255.255.255 -arp up # echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore # echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce # echo 0 >/proc/sys/net/ipv4/conf/tunl0/rp_filter