BROCADE IP PRIMER

Chapter 12: Multi Protocol Label Switching (MPLS)Summary• In an MPLS network, data packets are assigned labels, and the packetforwardingdecisions are based solely on the contents of this label.• MPLS works by prefixing packets with an MPLS header, containing one ormore “labels.” Each label stack entry contains the following four fields:— A 20-bit label value— A 3-bit Class of Service and Explicit Congestion Notification (ECN)— A 1-bit end of stack— A 8-bit time to live field• MPLS requires a Layer 3 topology to operate. Brocade utilizes OSPF toprovide routing in the MPLS cloud.• MPLS VLL is a method of providing point-to-point Ethernet /VLAN connectivityover an MPLS domain.• VPLS enhances the point-to-point (VLL) connectivity by specifying amethod for Virtual Circuits (VC) to provide point-to-multipoint connectivityin the MPLS domain.• In the MPLS VPN backbone, the label stack is used to forward VPNpackets.• A route-target extended community, or route target, is a type of BGPextended community that you use to define VPN membership.There are no review questions and answers for this chapter.270 Brocade IP Primer