Innovation challenges in core networks

1. New challenges on optical control plane standardization Juan Pedro Fernandez-Palacios, Telefonica I+D (Spain)

2. Innovation challenges in core networks • IP Network End to End MPLS network E2EMPLS – gluing segments to simplify operation and provisioning Separated provisioning and OAM in different segments (IP & Aggregation). End-to-end MPLS solutions to lower OPEX IP/MPLS core MAN MAN • Multilayer coordination Resource optimization through multilayer planning. OPEX savings from coordinated planes. Photonic Control Plane Multilayer Coordination to optimize resources Photonic Control Plane GMPLS + PCE Allowing cost efficient Multivendor network Multi-vendor interoperability Algorithms for Efficient use of available resources ROADM Photonic Transport Transmission Fiber link Cost efficient high speed transmission up to 1 Tbps- Flexible Grid. Pure optical subwavelength switching. ROADM Cost Efficient Photonic Transport Network 100 Gbps+ Variable rate transponder ROADM ROADM Flexible Grid

3. Automated Network Creation by multilayer interworking Current Network CreationProcess Hours/Days Hours/Days Hours Hours • Very costly • Time • Money • Human dependent

4. Automated Network Creation by multilayer interworking Automated Network CreationProcess < 1 second < 1 second Seconds

5. Multi-layer target architecture Current Isolated layers Manual Coordination Automated Coordination Integration? • The target multi-layer control plane to enable automatic operation and coordinated protection is based on: • Hierarchical LSPs and Forwarding Adjacencies  Scalability. • Extended UNI interface: • UNI enables automatic transport connection set-up. • Extended UNI allows multi-layer information dissemination (TE-link, SRLGs, etc.), simplifying operation and resource utilization. • Multi-layer PCE  Enable scalable resource optimization and interconnection. • Configuration mechanisms enabling automated IP routers configuration according to the new physical topology IP/MPLS Layer IP/MPLS Layer IP/MPLS Layer IP/MPLS + Transport PCE UNI Ext. UNI Photonic Transport Layer Photonic Transport Layer Photonic Transport Layer Interoperability Lack of Standardization • Inefficient resource utilization • Manual operation (IP and transport) • Duplicated protection • Improved resource utilization • Automated operation (MPLS and transport) • Coordinated protection • Automated operation (only at transport level) • Optimum resource utilization

6. Key elements enabling multilayer interworking • Current core networks are based on several layers. • Mid-term scenario: IP/MPLS network over reconfigurable wavelength switched optical network (WSON). • Three key elements to help in the management and coordination of such multi-layer architectures: • User to Network Interface (UNI) • Path Computation Element (PCE) • Virtual Network Topology Manager (VNTM). • UNI standard method to allow resource request between layers acting as server and client • PCE aim is to calculate the route between endpoints, especially in complex scenarios • VNTM is in charge of maintaining the topology of the upper layer by connections in the lower layer.

7. Multilayer Interworking: UNI • UNI: standard method to allow resource request between layers acting as server and client. • E.g. can be used to establishment of a new adjacency on demand between two IP/MPLS routers through a transport network • Current state of the art UNI is focused on signalling • No exchange of routing information • No exchange of SRLG information • Extensions to the UNI to send reachability information from the server layer to the client layer are being proposed

8. Multi-DomainInterworking: H-PCE • Two alternatives were considered at Telefonica: • Multidomain OSPF over E-NNI preferred option • Hierarchical PCE: PCEs exchange information about their network topologies PCE ROADM ROADM ROADM ROADM OSPF OSPF PCE PCE E-NNI OSPF PCE E-NNI ROADM ROADM ROADM ROADM ROADM ROADM ROADM ROADM ROADM ROADM ROADM Subwavelength domain. Vendor A Subwavelength domain. Vendor C OTN/WSON domain. Vendor B Hierarchical PCE: This option reduces OSPF traffic, supports different routing protocol implementations in each domain (e.g OSPF proprietary extensions) and allows networks operators to select the optimum e2e algorithm for their networks

9. Multi-DomainInterworking: H-PCE • Hierarchical PCE • Parent PCE with visibility of inter-domain topology and Child PCEs • No need to know sequence of domains in advance • Better scalability and results 4-I chose candidate inter-domain links and ask all other PCEs 7-Use received information to compute best route TOP PCE 5-Give me the path from I to O and the path from N to O 3-Best path to “O”? 6-The paths are A-B-C and A-G-H 2-Outside my Domain 5-Give me a path from A to C and a path from A to H. C B 8-Best path is A-G-H-N-O 6-The paths s are I-J-K-O and N-O PCE2 A 9- Use G-H-N-O PCE1 D F I J 1-Path to “O”? G H K O M L N 8

10. Multi-DomainInterworking: H-PCE Architecture in the Distributed Multi-Platform Control Plane Testbed

11. Flexgrid Control Plane • ITU-T SG-15 is extending the standard G.694.1 to include the concept of flexible grid • Goal: allow an efficient and flexible allocation and configuration of optical spectral bandwidth for high bit-rate systems. • Currenlty ITU-T is extending the architecture of the optical transport networks (G.782) to add the flexi-grid layer (also referred to as the media layer) as the server layer of the optical channels. • IETF is starting to look at the definition of the GMPLS based control of the flexible grid networks • Several frameworks and solutions from different companies were presented • In the 84th IETF meeting in Vancouver, the Framework for GMPLS based control of Flexi-grid DWDM networks joining for the first time all the efforts of the industry, led by FP7 STRONGEST partners (Telefonica and CTTC), draft-ogrcetal-ccamp-flexi-grid-fwk-00 was presented. • All the control plane extensions (signalling, routing, path computation) need to be done… still a lot of work ahead…

12. Subwavelength Switching Control Plane • Photonic sub-wavelength technologies are being developed by multiple vendors as a suitable solution for Metro Area Networks (MAN) • Many Optical packet switching (OPS) and optical burst switching (OBS) technologies and architectures have been proposed to support sub-wavelength services • However, photonic sub-wavelength standardization is just starting

13. ITU-T Terminology for Sub-Lambda Photonically Switched Network (SLPSN) • SLPSN definition: SLPSN is a switching technology which handles, at the data plane level and in a photonic way, temporal slices of individual or multiple wavelengths. SLPSN incorporates the optical time domain in addition to the wavelength/frequency and space domains. • SLPSU definition: a sub-lambda photonic switching unit (SLPSU) is an optically sliced unit of a wavelength in time domain, such as an optical time slot, an optical burst, or an optical packet.

14. GMPLS extensions for SLPSN: MAINS approach

15. Conclusions • Mulilayercoordination • The current standards need to be extended to suggest new configurations (e.g. new TE-Links) to the VNTM. • UNI is currently being extended • Multilayer PCE, VNTM and UNI can cooperate together • They have proven to be feasible elements for the automatic operation of an overlay MPLS over WSON network. • PCEP is a suitable protocol to communicate to the VNTM. • Multidomainopticalnetworks • Hierarchical PCE is a goodcandidatetoenablemulti-domaininterworking. • Standardization of H-PCE isontheway. • Subwavelegths • Commomtermionolgy is being standardized at ITU-T • GMPLS extensions to be proposed at IETF • Flexgrid • ITU is standardizing the date plane • Frawework has just started in IETF… GMPLS/PCE extensions to be done.

16. Acknowledgement • The research leading to these results has received funding from the European Union's Seventh Framework Programme ([FP7/2007-2013] [FP7/2007-2011]), STRONGEST, MAINS, ONE.