Netgear XCM8806 Chassis User Manual - Page 780

30. vMAN (PBN) 30 This chapter includes the following sections: • Overview on page 780 • Configuration on page 784 • Displaying vMAN Information on page 788 • Configuration Examples on page 788 Overview The virtual metropolitan area network (vMAN) features allow you to scale a Layer 2 network and avoid some of the management and bandwidth overhead required by Layer 3 networks. The following sections provide more information on these features: • vMANs (PBNs) on page 780 • vMAN Configuration Options and Features on page 782 Note: If a failover from MSM A to MSM B occurs, vMAN operation is not interrupted. The system has hitless failover-network traffic is not interrupted during a failover. vMANs (PBNs) The vMAN feature, which is also called the PBN feature, is defined by the IEEE 802.1ad standard, which is an amendment to the IEEE 802.1Q VLAN standard. Metropolitan area network (MAN) service providers can use a vMAN to carry VLAN traffic from multiple customers across a common Ethernet network. The vMAN uses Provider Bridges (PBs) to create a Layer 2 network that supports vMAN traffic. The vMAN technology is sometimes referred to as VLAN stacking or Q-in-Q. Figure 96 shows a vMAN, which spans the switches in a MAN. 780