IBM L2VPN Services
In a Layer 2 service, Tata Communications provides a point-to-point EoMPLS tunnel with Dot1Q tagging (ERS/EVPL, VLAN non-transparent), and you manage IP addressing and BGP directly with IBM. Two BGP sessions (primary and secondary) are established by default for redundancy, and failover is yours to manage.
How Layer 2 delivery works
For a Layer 2 service, Tata Communications configures an EoMPLS tunnel from your terminating MPLS PE router to the IBM-interconnect MPLS PE router. IBM supports Dot1Q (C-tag), so Tata Communications applies Dot1Q tagging to hand your traffic off to IBM. The Tata Communications network acts purely as a Layer 2 tunnel (L2VPN on ERS/EVPL): you configure IP addressing on your CPE and in IBM, and BGP peering runs between your CPE and IBM, managed by you. Your last mile must support Dot1Q, and Tata Communications assigns a different VLAN for each of the primary and secondary services.
Resiliency on Layer 2
Two BGP sessions (primary and secondary) are established by default to match IBM’s standard resiliency. Traffic failover is managed by you, using routing between your CPE and IBM.
Layer 2 limitations
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Two VLANs/VCs are created where you subscribe to a redundant (dual-link) service.
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VLAN transparency is not supported – the EoMPLS tunnel runs in ERS/EVPL mode.
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Single-tag 802.1Q only – QinQ (EWS mode) is not supported on the direct Layer 2 service.
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Multi-site Layer 2 (VPLS) is not supported.
Layer 2 over the partner-routed path
Where the Layer 2 service is delivered over the partner-routed path, the EoMPLS tunnel runs to the partner-connected MPLS PE, with the interconnection partner using QinQ as the transit. The customer-managed IP and BGP model is otherwise the same.