Bi-directional flow stickiness in a network environment

摘要

An example method for bi-directional flow stickiness in a network environment is provided and includes receiving a packet of a flow from a source address in a network, and destined to a destination address outside the network, looking up a flow table for an entry corresponding to the flow, and caching a forward flow entry and a reverse flow entry in the flow table if the look up results in a miss, the forward flow entry indicating a routing lookup, and the reverse flow entry indicating a previous hop from which the packet was received to maintain a bi-directional flow stickiness. Some embodiments also include receiving another packet from the destination address outside the network destined to the source address in the network, and forwarding it to the previous hop listed in the reverse flow entry.

主权项

1. A method executed at a forwarder in a network, the method comprising:
receiving a packet of a forward flow from a service node in the network, wherein the forward flow is subject to a plurality of service functions performed at respective service nodes in the network between a source of the packet in the network and a destination of the packet outside the network, wherein the packet is processed at the service node according to a particular service function; looking up a flow table for an entry corresponding to the forward flow; and if the look up results in a miss, caching a forward flow entry in the flow table, the forward flow entry indicating an action comprising an instruction to look up a forwarding table if the forwarder is a designated forwarder, and another instruction to forward the packet to the designated forwarder if the forwarder is a non-designated forwarder, wherein the designated forwarder for the particular service function is the only forwarder that can forward packets of the forward flow to a different service function or to a gateway according to the forwarding table, wherein the non-designated forwarder for the particular service function can only forward packets of the forward flow to the designated forwarder; and generating a reverse flow entry in the flow table indicating another action to forward any packets in a reverse direction of the forward flow to a previous hop from which the packet was received, wherein the previous hop comprises the service node if the service node is directly connected to the forwarder, wherein the previous hop comprises the non-designated forwarder if the service node is not directly connected to the forwarder, wherein packets in the reverse direction of the forward flow traverse the respective service nodes in reverse direction, wherein the reverse flow entry facilitates maintaining a bi-directional flow stickiness with respect to the service nodes.