WB.15.15

are encapsulated, the path that the encapsulated packet traverses must be configured with a larger

MTU.

Up to 16 unique tunnel interfaces can be created to actively forward traffic.

NOTE: Tunnels are IPv4 only. IPv6 tunnels are not supported in the current version.

Tunnel Creation

Tunnels can be created using SNMP. The switch manages tunnels, with each tunnel being

represented by a unique interface index. First the application (such as the HP Network Protector

SDN Application) queries a switch to determine if it supports configuring tunnels. This is via an

SNMP object that returns the number of tunnel interfaces supported on the switch. Once it is

determined that tunnels can be configured, the controller can move on to creating the appropriate

interface.

The following sequence diagram explains the process of creation of a tunnel.

Figure 2 Tunnel Creation

Tunnels are not hitless. A switch management module failover results in tunnels being removed

from hardware and OpenFlow rules pointing to these tunnels will drop frames.

NOTE: Tunnel-related configuration information is non-volatile and cannot be restored after a

device reboot. The controller has to re-create the tunnel interface in the event that the switch reboots

and comes back up.

Tunnel Deletion

The application can delete the tunnel interface it created using SNMP. The switch does not check

if there are any active OpenFlow rules using that tunnel but goes ahead and deletes the interface.

If there are active flow rules that are using a tunnel, traffic matching those flow rules are dropped

because the tunnel has been deleted.

Once a tunnel interface has been deleted, the OpenFlow agent communicates the same to the

controller as a logical port removal notification. The agent doesn’t remove any flow rules that use

Hardware IP Tunnels 5