Addressing And End-To-End Glsp Architecture - Alcatel-Lucent 7450 Manual

Addressing and End-to-End gLSP Architecture

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Although the architecture figure shows a single 7x50 connected to a single UNI-N (1830 PSS), it
is possible to multi-home a 7x50 into more than one (usually two) UNI-Ns at the edge of the
optical network. In this case, a separate IPCC, set of data bearers, and set of TE links, is required
between the 7x50 and each UNI-N.

Addressing and End-to-End gLSP Architecture

The GMPLS UNI assumed a flat addressing scheme between the UNI-C nodes and the optical
network. In this model, a common addressing scheme is used between the UNI-C (IP router) and
UNI-N (optical edge). The UNI-C and UNI-N must be in the same subnet. Also, none of the UNI-
C addresses can overlap or clash with any of the GMPLS-aware nodes in the optical network. This
does not mandate that the whole IP network share a common address space with the optical
network, as a separate loopback address can be used for the GMPLS UNI on the UNI-C.
ERO Expansion (RFC 5151) model is assumed for the GMPLS LSPs. The UNI-C is not exposed
to the full ERO between the UNI-N nodes. Instead, the full ERO is inserted at the UNI-N. This
model limits the sharing of SRLG information between the UNI-N and UNI-C.
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gLSP — The GMPLS LSP. At the UNI-C, this is a control plane object representing the
TE-Link in the RSVP-TE control plane. Although this is an LSP, there is no explicit
MPLS label in the data path at the UNI-C; the gLSP maps to a data bearer of the TE link to
/ from the UNI-N. When a gLSP is signaled to a far-end UNI-C node, the optical network
establishes bidirectional connectivity between one of the data bearers in the TE link on the
UNI-N at the ingress to the optical network, and one of the data bearers on the TE link on
the egress UNI-N node connected to the far end UNI-C node.
Network Interface — When a gLSP is successfully established, a network interface can be
bound to the gLSP. The network interface then uses the data bearer associated with the
gLSP to forward traffic. This network interface can be used by any applicable protocol
associated with an overlying IP/MPLS network. The network interface is bound to the
gLSPs via a GMPLS tunnel group.
7450 ESS MPLS Guide