© Copyright Lenovo 2016 Chapter 22: Edge Virtual Bridging 393Chapter 22. Edge Virtual BridgingThe 802.1Qbg/Edge Virtual Bridging (EVB) is an emerging IEEE standard forallowing networks to become virtual machine (VM)‐aware. EVB bridges the gapbetween physical and virtual network resources. The IEEE 802.1Qbg simplifiesnetwork management by providing a standards‐based protocol that defines howvirtual Ethernet bridges exchange configuration information. In EVBenvironments, physical end stations, containing multiple virtual end stations, use abridge to form a LAN. The virtual NIC (vNIC) configuration information of avirtual machine is available to these EVB devices. This information is generally notavailable to an 802.1Q bridge.Lenovo Enterprise Network Operating System EVB features are compliant withthe IEEE 802.1Qbg Authors Group Draft 0.2. For a list of documents on this feature,see: http://www.ieee802.org/1/pages/802.1bg.html.The Lenovo RackSwitch G8264 performs the role of a 802.1Qbg bridge in an EVBenvironment.Enterprise NOS implementation of EVB supports the following protocols: Virtual Ethernet Bridging (VEB) and Virtual Ethernet Port Aggregator (VEPA):VEB and VEPA are mechanisms for switching between VMs on the samehypervisor. VEB enables switching with the server, either in the software(vSwitch), or in the hardware (using single root I/O virtualization capable NICs).VEPA requires the edge switch to support “Reflective Relay”— an operationwhere the switch forwards a frame back to the port on which it arrived if thedestination MAC address is on the same port. Edge Control Protocol (ECP): ECP is a transport protocol that operates betweentwo peers over an IEEE 802 LAN. ECP provides reliable, in‐order delivery ofULP (Upper Layer Protocol) PDUs (Protocol Data Units). Virtual Station Interface (VSI) Discovery and Configuration Protocol (VDP):VDP allows hypervisors to advertise VSIs to the physical network. This protocolalso allows centralized configuration of network policies that will persist withthe VM, independent of its location. EVB Type‐Length‐Value (TLV): EVB TLV is a Link Layer Discovery protocol(LLDP)‐based TLV used to discover and configure VEPA, ECP, and VDP.
