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GMPLS-Based Control Plane for Optical Networks. June-Hyun, Moon Computer Communications LAB., Kawangwoon University imp@kw.ac.kr. Introduction to Generalized MPLS. IP/MPLS-based distributed control plane Automatic service provisioning
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GMPLS-Based Control Plane for Optical Networks June-Hyun, Moon Computer Communications LAB., Kawangwoon University imp@kw.ac.kr
Introduction to Generalized MPLS • IP/MPLS-based distributed control plane • Automatic service provisioning • Dynamic network topology and resource availability dissemination • Neighbor dsicovery and link management • Applicable to multiple network technologies with different capabilities • Packet-switch capable interfaces (e.g. routers) • TDM capable interface (e.g. SONET/SDH) • Lambda-switch capable interface (e.g. optical cross-connects) • Fiber-switch capable interface (e.g. photonic switches)
GMPLS Motivation • Interoperability • Across multi-vendor transport network as well as their clients • Provides integrated control plane for multiple types of equipment • High scalability for large, dynamic network with many connections/LSPs • Simplifies end-to-end provisioning • Facilitates unified traffic engineering • Peer-to-peer • Overlay • Allows de-coupling control and data channels
Standardization Activities • IETF • Extends MPLS/IP protocols based on generalized interface requirements • Signaling (RSVP-TE and CR-LDP with GMPLS extensions) • Routing (OSPF-TE and IS-IS with GMPLS extensions) • Neighbor discovery and link managements (LMP) • OIF • Focuses on application of IETF protocols in an overlay model • Generates implementation agreements • UNI 1.0 (approved in October 2001) • NNI (in progress) • ITU • Automatic Switched Optical Network (ASON) • UNI and NNI interfaces
GMPLS Application – GMPLS manager • Coodinates the functions of all GMPLS control plane modules • Communicates with EMS/NMS or external management systems • Creates and deletes signaling and routing interfaces • Performs admission control • Executes connection setup and teardown requests • Provides the interface between the control plane and the actual data plane • Set up and teardown cross connects
GMPLS Manager • State Machine • Manages LSP operation • Facilitates multitasking and error handing • Database • Maintains allocated and ready-to-use resource information • Tracks the state of existing connections • Two Sub-modules • GMPLS controller • Performs control functions • GMPLS adapter • Provides an interface to the routing and signaling components
Routing • Disseminates network topology and resource availability • Manages the link state database and routing tables • Provides the routing information to the routing component users • Access the routing information • Make routing decision • Obtain explicit route • OSPF GMPLS extensions • Support traffic engineering over different types of links • Link bundling • Aggregates and abstracts the attributes of the links with similar characteristics between a pair of nodes • Advertised as a single link bundle or TE link • Reduces the amount of information handled by routing component • Improves routing scalability • Aggregation leads to information loss
Path Computation • Explicit route for the requested LSP computed at the ingress node • Takes into account a set of constraints • Resource availability • Bandwidth requirements • Protection/restoration (e.g. 1+1, shared mesh) • Traffic engineering constraints • Not subject to standardization
Signaling • Extablishes and deletes signaling sessions with neigbor signaling peers • Processes LSP-related requests the GMPLS manager • Generates appropriate control messages • Sends them along the path • Receives and decodes incoming messages • Passes the appropriate notifications to the GMPLS manager for action • Callback functions • LSP setup • Label request • Resource reservation and allocation • LSP deletion • Label and resource release
Signaling (cont.) • RSVP-TE with GMPLS extensions • Generalized label request and generalized label • Suggested label • Label set • Explicit label control • Bidirectional LSP • Notification on error • Protection information • Administrative status information • Control channel separation and fault handling
Neighbor Discovery and Link Management • Establishes and maintains control channel connectivity between neighbors • Configuration message • Keep-alive • Discovers and correlates the physical properties of data links • Test message • Link summary message • Verifies the data link connectivity • Localizes and handles link failure • Link fault management • Leads to local span or end-to-end recovery