Examplethere can be one label for routing the packet to an egress point and another. Need for easier configuration of sitetosite wan connectivity. In a layer 2 vpn, l2 frames usually ethernet are transported between locations. Rather, it simply maps incoming layer 2 traffic onto the appropriate pointto. An indepth view of mpls vpns can be gained by reading sections4and5. Commonly known scheme for building layer 2 circuits over mpls. Layer 2 vpn is not supported on the ex9200 virtual chassis. In this document i will be covering how to configure l2 mpls vpn over service provider cloud. Virtual private networking vpn traffic engineering te quality of service qos. Multiprotocol label switching multiprotocol label switching mpls is a layer2 switching technology. Mpls emulates some properties of a circuitswitched network over a packetswitched network since it allows most packets to be forwarded at the layer 2 data link layer level rather than at layer 3 network layer.
Virtual private networks washington university in st. Layer 2 mpls vpns often called martini vpns after the primary author of the ietf draft allow service providers to deliver to their customers secure, layer 2 connections over mpls core networks. Multiprotocol label switching mpls converts routed network to something closer to a switched network and offers information transfer speeds that are not available in a. Bgpmpls vpn architecture overview vpn routing and forwarding vrf. Ldp is typically used by mpls vpn data transport services. To support an mplsbased layer 2 vpn, you need to add components to the configuration of the two provider edge pe routing devices. The basic components of a layer 3 vpn are the p, pe and ce routers.
Mpls layer 2 vpn is similar in function and configuration as l2tpv3 layer 2 tunnel protocol version 3. In the more general case, its similar to a cable connecting two switches in separate buildings. Part 2 will cover the following tasks and topics on how to share routing information between difference customers or vrf in an mpls vpn network. This is the reason why it is commonly referred to as. Mpls for dummies north american network operators group. I take a high level overview of the different pieces of mpls vpns and how they all work together. Internet service providers isps would like to replace their frame relay fr or asyn. Cisco layer 2 vpns l2vpn training workbook for network. Multiprotocol label switching mpls label switching.
From providers perspective client is asking for layer 2 vpn connection between their 2 sites as well as they wants their 2 sites router will discover one another by layer 2 such as cdp. Configure static routes between two vrfs custb and global routing table customer c. This lesson is the foundation lesson for the mpls vpn curriculum. Mpls layer 2 devices run a layer 3 routing protocol and establish virtual circuits dynamically based on layer 3 information. Some benefits of a layer 2 vpn are that it is private, secure, and flexible. On ex9200 switches, graceful routing engine switchover gres, nonstop active routing nsr, and logical systems are not supported on layer 2 vpn configurations. Implementing mpls layer 2 vpns this module provides the conceptual and configuration information for mpls layer 2 virtual private networks vpns on cisco ios xr software. Cisco ios xr virtual private network configuration guide for the cisco crs router ol2466901. For other layer 2 types such as ethernet and ppp the label is added to the data packet in an mpls shim header, which is placed between the layer 2 and layer 3 headers. The only manual configurations required are at the. It can be configure in two ways, one way to use l2 vpn over ip cloud with the help of l2tpv3 and another way is to use over mpls backbone by using encapsulation mpls. L2mtu layer 2 and layer 3, save space of data l2mtu. Rfc 2547 is an ietf informational document only and rfc 2547bis is an internet draft. Configuring layer 2 mpls vpn mplsvpn moving towards sdn.
Lsps are a sequence of labels at each and every node along the path from the source to the. Please check out the new mpls l3 vpn video series link below. The first part of the session covers the drivers, the. Mpls solution, a modular suite of network and service management applications, is a network management system that defines and monitors virtual private network vpn. An mpls vpn is a virtual private network built on top of a service providers mpls network to deliver connectivity between enterprise locations. Vpls qinq or portbased l2tpv3 using static tunnels mpls vpn ospf and eigrp routing. The result is that a single packet could be propagated with three l2 hops but instead requires 7 hops. For example, a label could correspond to an atm vpivci, a frame relay dlci, or a dwdm wavelength for optical networking. In the last article, we discussed the basic configuration of mpls layer 3 vpn. Mpls layer 2 vpn functions in the same way but is used in the mpls environment. Mpls l2l3 virtual private networks vpns an ipmpls forum sponsored tutorial dave christophe ipmpls forum education wg.
P routers do not participate in mpls vpn routing and do not carry vpn routes. The layer2 vpn solution is a simple and low maintenance solution, and that is a considerable strength, but tutprial has a weakness. For this reason, mpls has been referred to as operating at layer 2. It is a method that internet service providers use to segregate their network for their customers, to allow them to transmit data over an ip network. Florin balus, nortel mike loomis, nortel this tutorial discusses the l2 vpnovermpls solutions being standardized in the ietf. These two protocols provide a pseudowire service, which means that. Mpls uses a 32bit label field that is inserted between layer 2 and layer 3 headers framemode mpls. Atm, and framerelay layer2 protocols in mpls, data transmission occurs on labelswitched paths lsps. For the functionality of mpls vpns over ip tunnels, see implementing mpls vpns over ip tunnels in cisco ios xr virtual private network configuration guide. Designing and implementing ipmplsbased ethernet layer 2. A layer 2 mpls vpn is a term in computer networking.
Mpls tutorial jonpaul herron abilene noc jointtechs columbus july 18, 2004. It operates at a layer that is generally considered to lie between traditional definitions. Mpls layer 2 vpns functional and performance testing. This figure illustrates a worstcase scenario where layer 2 l2 and layer 3 l3 topologies do not overlap. Multiprotocol label switching mpls is a versatile solution to address the. A layer 2 only ethernet switch which does exact matching may be 14th the cost and 4x the. Understanding layer 2 vpns techlibrary juniper networks. Mpls solution provisioning and operations guide doc7812189 1 introduction to cisco mpls vpn technology technology overview the cisco vpn solutions center. The communication occurs between routers that are known as provider edge routers pes, as they sit on the edge of the providers network, next to the customers network. Mpls can provide the required tunneling mechanism mpls can be used to provide traffic engineered pepe tunnels an additional mpls label can also used to associate packets with a vpn layer 3 mplsbased vpns bgpmpls vpns rfc 2547bis layer 2 mplsbased vpns. Mpls configuration step by step cisco mpls tutorial. Hi reader today i am going to explain you, how mpls works in this mpls tutorial.
Layer 2 vpns layer 2 mpls vpns provide a virtual layer 2 connection overlay across an mpls network. It is for layer 2 connectivity only, layer 3 is transparent to mpls core. Multi protocol label switching mpls is an efficient encapsulation mechanism uses labels appended to packets ip packets, aal5 frames for transport of data mpls packets can run on other layer 2 technologies such as atm, fr, ppp, pos, ethernet other layer 2 technologies can be run over an mpls network. If you are looking for an mpls tutorial or step by step mpls configuration examples, this basic mpls vpn configuration example will guide you from configuring the first router to a 3 router mpls core with 2 external sites.
Layer 2 vpn emulates the behavior of a local area network lan across an internet protocol ip or mplsenabled ip network allowing ethernet devices to communicate with each other as if they were connected to a common lan segment. Mpls is multiprotocol label switching is mostly found in service provider networks. Vpn allows secure communication on the internet three types. Mpls based virtual private network services mpls vpn tutorial.
Layer 2 covers protocols like ethernet and sonet, which can carry ip packets, but only over simple lans or pointtopoint wans. Layer 3 covers internetwide addressing and routing using ip protocols. Available in layer 2 or layer 3 options, the vpn leverages the multiprotocol and labeling capabilities of mpls to deliver a flat, peertopeer network to link. In a layer 2 mpls vpn, the pe router is not a peer to the ce router and does not maintain separate routing tables. Mpls reduces cpuusage on routers, by allowing routers to make. Mplsenabled routers apply numerical labels to packets, and can make forwarding decisions based on these labels. Vpls virtual private lan service is a service that uses mpls and vpn virtual private networking to securely and seamlessly connect multiple lans over the internet, making. The 1st mpls tag exists only to enable mpls forwarding plane operations. A layer 2 vpn provides complete separation between the providers network and the customers networkthat is, the pe devices and the ce devices do not exchange routing information. Mpls allows qos, security strict traffic rules mpls vpns operate at layer 2 or layer 3 corporate routers dont need to support mpls. Mpls layer 2 vpns functional and performance testing sample test plans. Layer 3 mpls vpns are based on rfc 2547 and 2547bis. Mpls layer 2 vpn can anyone help me to understand the issue.
Home ccie mpls mpls configuration tutorial step by step. This is the most basic feature of mpls so it is used in all mpls networks even if there is no vpn overlay. With igp reachability, simple edge configuration is the only thing required. L2tpv3 is used to tunnel layer 2 over ip networks and is widely used on the internet. You do not need to change the configuration of the provider devices. A virtual private network vpn allows the provisioning of private network services for an. Destination unicast address traffic engineering vpn qos. Layer 2 vpns are a type of virtual private network vpn that uses mpls labels to transport data. Multi protocol label switching mpls is a datacarrying mechanism in packetswitched networks. Mpls concepts unlike ip, classificationlabel can be based on. Mpls lspsan lsp is a path via label switch routers lsr in an mpls network. In the past the old days we have layer 2 virtual circuits provided courtesy of our service provider a virtual circuit would be an overlay normally from side a to side b.
1465 1340 880 1475 755 495 128 722 267 546 886 250 347 610 720 905 524 785 274 797 1213 895 832 393 1032 138 946 700 1320 1252 213 1151 938 137 1106 552 1024 709 1207 660 490 1117 1393 1163 571 146 1176