Service control plane messaging in service data plane

Some embodiments provide novel methods for performing services for machines operating in one or more datacenters. For instance, for a group of related guest machines (e.g., a group of tenant machines), some embodiments define two different forwarding planes: (1) a guest forwarding plane and (2) a service forwarding plane. The guest forwarding plane connects to the machines in the group and performs L2 and/or L3 forwarding for these machines. The service forwarding plane (1) connects to the service nodes that perform services on data messages sent to and from these machines, and (2) forwards these data messages to the service nodes. In some embodiments, the guest machines do not connect directly with the service forwarding plane. For instance, in some embodiments, each forwarding plane connects to a machine or service node through a port that receives data messages from, or supplies data messages to, the machine or service node. In such embodiments, the service forwarding plane does not have a port that directly receives data messages from, or supplies data messages to, any guest machine. Instead, in some such embodiments, data associated with a guest machine is routed to a port proxy module executing on the same host computer, and this other module has a service plane port. This port proxy module in some embodiments indirectly can connect more than one guest machine on the same host to the service plane (i.e., can serve as the port proxy module for more than one guest machine on the same host).