TCP/IP Tutorial and Technical Overview - IBM Redbooks

► The effort can provide a single architecture, allowing an LSP to traverse a mix
of router and OXC devices. This positions the network to provide real
bandwidth on demand facilities.
► The effort positions IP routers for the eventual incorporation of high-capacity
dense wave division multiplexing (DWDM) capabilities.
► It provides new services such as Optical Virtual Private Network or Optical
VPN, and Differentiated Circuit with service-level assurance.
► It enhances bandwidth brokering with instant bandwidth on demand
capability.
► It also standardizes ways to handle connections through automatic
provisioning.
► GMPLS extends the MPLS protocol so that it can control not only routers, but
also:
– Dense wavelength division multiplexing (DWDM) systems
– Add drop multiplexers
– Optical cross-connects
– Optical switches
A.4.2 MPLS and GMPLS comparison in OTN environment
The extension of MPLS functions into optical network is based on a number of
similarities between the two types of networks:
► In MPLS, an LSP describes the point-to-point path traversed by a set of
labeled packets. In GMPLS, an optical channel trail is used to describe the
point-to-point optical connection between two access points.
► In an MPLS network, an LSR establishes a relationship between an tuple and tuple. Similarly, in an
optical transport network, an OXC establishes a relationship between an
tuple and tuple. When established, these relationships cannot be altered by
the contents of any data packet.
► In an MPLS network, an LSR discovers, distributes, and maintains state
information associated with the network. An OXC is responsible for these
same functions in an OTN.
► In an MPLS network, an LSR is responsible for creating and maintaining
LSPs associated with existing traffic engineering policies. An OXC is
responsible for the same functions in an OTN.
► In an MPLS network, an LSP is unidirectional. In an OTN, an optical channel
trail is also unidirectional.
942 TCP/IP Tutorial and Technical Overview