mpls layer 2 la gi

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Logical View of a Layer 2 MPLS VPN.

A Layer 2 MPLS VPN is a term in computer networking. It is a method that Internet service providers use to tát segregate their network for their customers, to tát allow them to tát transmit data over an IP network. This is often sold as a service to tát businesses.

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Layer 2 VPNs are a type of Virtual Private Network (VPN) that uses MPLS labels to tát transport data. The communication occurs between routers that are known as Provider Edge routers (PEs), as they sit on the edge of the provider's network, next to tát the customer's network.

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Internet providers who have an existing Layer 2 network (such as ATM or Frame Relay) may choose to tát use these VPNs instead of the other common MPLS VPN, Layer 3. There is no one IETF standard for Layer 2 MPLS VPNs. Instead, two methodologies may be used. Both methods use a standard MPLS header to tát encapsulate data. However, they differ in their signaling protocols.

Types of Layer 2 MPLS VPNs[edit]

BGP-based[edit]

The BGP-based type is based on a draft specification by Kireeti Kompella, from Juniper Networks. It uses the Border Gateway Protocol (BGP) as the mechanism for PE routers to tát communicate with each other about their customer connections. Each router connects to tát a central cloud, using BGP. This means that when new customers are added (usually to tát new routers), the existing routers will communicate with each other, via BGP, and automatically add the new customers to tát the service.[1]

LDP-based[edit]

The second type is based on a draft specification by Chandan Mishra from Cisco Systems. This method is also known as a Layer 2 circuit. It uses the Label Distribution Protocol (LDP) to tát communicate between PE routers. In this case, every LDP-speaking router will exchange FECs (forwarding equivalence classes) and establish LSPs with every other LDP-speaking router on the network (or just the other PE router, in the case when LDP is tunnelled over RSVP-TE), which differs from the BGP-based methodology. The LDP-based style of layer 2 VPN defines new TLVs and parameters for LDP to tát aid in the signaling of the VPNs.[2]

Vendor implementations[edit]

  • Alcatel-Lucent: LDP based
  • Foundry Networks: LDP-based (NetIron XMR Series, NetIron MLX Series)
  • Juniper Networks: BGP-based (MX/M/T/J-series)
  • Juniper Networks: LDP-based (MX/M/T/J/E-series)
  • Cisco Systems: LDP-based (IOS)
  • Cisco Systems: LDP-based and BGP-based (IOS XR)
  • Cisco Systems: LDP-Based [BGP-DISC][1]
  • MRV communications [2]: LDP-based
  • Lucent Technologies (formerly Riverstone Networks): LDP-based
  • Ericsson (formerly Redback Networks): LDP-based
  • Huawei Technologies: LDP-based & BGP-based (NE/S-series)
  • ZTE:LDP-based & BGP-based (ZXCTN6000/9000 series, ZXR10 series)

References[edit]