--- /dev/null
+# Alternatives for underlay network management from OSM #
+
+## Proposer ##
+**EUAG**
+
+## Type ##
+**Feature**
+
+## Target MDG/TF ##
+RO, UI
+
+## Description ##
+Most common VIMs (Openstack, VMware, AWS) do not provide management of native L2
+underlay connections (E-Line, E-LAN) suitable for EPA. In the case of Openstack,
+there are proprietary solutions based on neutron ML2 plugins for the
+connectivity of SR-IOV interfaces. However, those solutions are not suitable for
+all use cases:
+
+* It is not possible to connect PT (pass-through) NIC interfaces (there are no
+neutron ports associated to PT interfaces).
+* It is also impossible to connect multitenant VNFs (using VLAN tags per tenant)
+with single tenant VNFs, where the VLAN tag must be automatically removed/added
+by the network.
+
+The proposal is to enable OSM to manage underlay networks directly through an
+SDN controller (SDNC) whenever that feature is not provided by the VIM. In those
+cases, the VIM would only in charge of the creation of VM instances and the
+creation of overlay networks, while the SDNC, governed by OSM (the RO, in this
+case), would be in charge of the creation and deletion of underlay networks.
+
+It is devised that OSM should get from the VIM the physical allocation of the
+interfaces (SRIOV, PT) once the VM is deployed, and it will command the SDNC to
+connect these interfaces in E-Line or E-LAN networks. Common SDNCs that are
+expected to be supported should be ODL and ONOS.
+
+## Demo or definition of done ##
+N/A