A method comprising: creating, by a Software Defined Network,SDN, controller of a network system, a service chain comprising a plurality of Physical Network Functions,PNFs, (210A, 210B) including a first PNF and a second PNF, the service chain between a first logical router and a second logical router of the network system; creating, for each of the first PNF and the second PNF, a corresponding first routing instance (208A, 208C) and a corresponding second routing instance (208B, 208D); configuring, for each of the first PNF and the second PNF, the corresponding first routing instance with a first label comprising a first Virtual eXtensible Local Area Network VXLAN, Identifier,VNID, of a first virtual network associated with the first logical router and the second routing instance with a second label comprising a second VNID of a second virtual network associated with the second logical router; creating a first route between a first device on the first virtual network towards a second device on the second virtual network through the service chain, the first route specifying, in a first switch between the first device and the first PNF, the first VNID of the first routing instance of the first PNF as a first label for a next hop from the first switch to the first PNF, and specifying, in a second switch between the first PNF and the second PNF, the first VNID of the first routing instance of the second PNF as a second label for a next hop from the second switch to the second PNF; and pushing the first route to at least one of a plurality of switches (106A, 106B, 106C) communicatively coupled to one or more of the plurality of PNFs, the plurality of switches including the first switch and the second switch. creating, by a Software Defined Network,SDN, controller of a network system, a service chain comprising a plurality of Physical Network Functions,PNFs, (210A, 210B) including a first PNF and a second PNF, the service chain between a first logical router and a second logical router of the network system; creating, for each of the first PNF and the second PNF, a corresponding first routing instance (208A, 208C) and a corresponding second routing instance (208B, 208D); configuring, for each of the first PNF and the second PNF, the corresponding first routing instance with a first label comprising a first Virtual eXtensible Local Area Network VXLAN, Identifier,VNID, of a first virtual network associated with the first logical router and the second routing instance with a second label comprising a second VNID of a second virtual network associated with the second logical router; creating a first route between a first device on the first virtual network towards a second device on the second virtual network through the service chain, the first route specifying, in a first switch between the first device and the first PNF, the first VNID of the first routing instance of the first PNF as a first label for a next hop from the first switch to the first PNF, and specifying, in a second switch between the first PNF and the second PNF, the first VNID of the first routing instance of the second PNF as a second label for a next hop from the second switch to the second PNF; and pushing the first route to at least one of a plurality of switches (106A, 106B, 106C) communicatively coupled to one or more of the plurality of PNFs, the plurality of switches including the first switch and the second switch.