Centre Tecnològic de Telecomunicacions de Catalunya

ANNUAL REPORT 2013

ADRENALINE Test Bed ®

The ADRENALINE  testbed® is designed and developed by the CTTC Optical Networks and Systems Department for experimental research on high-performance and large-scale intelligent optical transport networks. It showcases a set of developed technologies:

  • SDN/OpenFlow controllers and agents: OpenFlow (OF), as a concrete implementation of Software Defined Networking (SDN), is an open standard (architecture and protocol) for a centralized control plane around the concept of an OF controller. This technology has been recently enabled in the ADRENALINE testbed, as a new centralized Control Plane solution for the Control and Management of packet and heterogeneous optical networks (e.g., fixed- and flexi-grid DWDM transport). The ADRENALINE testbed also includes a dedicated OpenFlow island for packet switched networks and an intra-data centre L2 OpenFlow Network An integrated PCE/OF controller with proprietary optical extensions has been developed, which communicates concurrently with each of the OF switches (i.e., OF agents) distributed along the network using the OF protocol and upon request.
  • Cloud Computing Datacentres: Several small scale datacentres with IT computing, storage and networking resources have been introduced in the ADRENALINE testbed. Also L2 OF switches have been deployed to provide intra-datacentre connectivity. The datacentres can be handled via proprietary tools and extensions upon OpenStack, which is an open source cloud computing solution.
  • OpenDaylight (ODL) proprietary extensions for Network Orchestration: ODL is the most important open source SDN controller, which can be used upon OF networks. ODL has been extended to support network orchestration towards different network control paradigms, such as GMPLS/PCE.  The introduced extensions allow ODL to support both intra-DC and inter-DC network connectivity.
  • Path Computation Element (PCE): ADRENALINE includes a PCE, which is a dedicated network entity responsible for doing advanced path computations. It combines, in a single system, a Path Computation Engine and a standard PCEP protocol interface to access Path Computation Services. The system is composed of a main PCE multi-threaded asynchronous process, running as a PCEP/TCP server in order to accept and process path computation requests from Path Computation Clients (PCC). The PCE serves requests from PCCs, and computes constrained explicit routes (EROs) over the topology that constitutes the optical transport layer. Different architectures can be deployed, including multi-domain path computation with Backwards Recursive Path Computation (BRPC) or with a hierarchical-PCE (H-PCE); multi-layer path computation in MPLS-TP over WSON networks, and stateful PCEs with instantiation capabilities. The PCE can also be used in an OpenFlow network and as a functional element in the scope of network virtualization, in order to virtualize data networks and services.
  • Wavelength Switched Optical Networks (WSON): an all-optical Dense Wavelength Division Multiplexing (DWDM) mesh network with two colourless Reconfigurable Optical Add-Drop Multiplexer (ROADM) nodes and two Optical Cross Connect (OXC) nodes provides high-bandwidth, reconfigurable (in space and in frequency) end-to-end lightpaths, transparent to the format and payload of the client signals (e.g., SONET/SDH, Gigabit Ethernet). The transport plane also includes non-intrusive Optical Performance Monitors and optical systems suitable to compensate the impact of physical impairments (e.g., All-Optical Wavelength Converter, Amplified Tunable Dispersion Compensator).
  • Network Virtualization (Virtualization): the network virtualization architecture of ADRENALINE is based on virtualizing both the GMPLS control and the WSON data planes. The virtualization of the GMPLS control plane allows creating virtual GMPLS connection controllers that can be used to deploy virtual networks with their own virtualized GMPLS control plane instance. The virtualization of the distributed GMPLS-based control plane relies on the usage of the GNU/Linux kernel KVM virtualization technology and the virtualization capabilities of the Intel ® CPUs (Intel VT). Once virtualized, the same physical machine hosts a configurable number of virtual guests, each replicating an OCC. With respect to the WSON data plane, the optical fiber switches and the controller cards of ROADM nodes support virtualization, being able to handle multiple TCP connections from virtualized OCCs. Finally, a new instance has been introduced so that the tunable transponders can also deal with several TCP connections from virtualized OCCs.
  • A GMPLS Unified Control Plane (GMPLS): Generalized Multiprotocol Label Switching (GMPLS) controllers have been designed and developed for implementing a distributed control plane, enabling the dynamic setup, management and release of data connections. This includes dedicated controllers for the WSON handling, dynamically and in real-time, the resources of the optical node in order to manage the automatic provisioning and survivability of lightpaths as well as an emulated network with up to 74 controllers for exhaustive performance evaluation. Each GMPLS controller executes several collaborative processes and the corresponding control plane protocols: the connection controller, executing the Resource Reservation Protocol–Traffic Engineering (RSVP-TE) signalling protocol, the routing controller, with the Open Shortest Path First–Traffic Engineering (OSPF-TE) routing protocol, the link management agent, with the Link Management Protocol (LMP) along with the Link Resource Manager (LRM) that manages the local resources, the hardware abstraction layers and drivers. The controllers are also manageable via the Simple Network Management Protocol (SNMP).
  • Carrier Ethernet Technologies (MPLS-TP/PWE3): ADRENALINE includes a connection-oriented IP/Ethernet Packet Transport Network (PTN), which is based on the Multiprotocol Label Switching–Transport Profile (MPLS-TP) and Pseudo-Wire emulation end-to-end (PWE3) architectures. The introduction of these technologies enabled the evolution of ADRENALINE from a single optical switching layer to dual-layer architecture. Three flexible GMPLS-controlled MPLS-TP/PWE3 nodes, implemented with the Click Modular Router software and with integrated 10Gb/s tunable DWDM transponders, have been deployed to enable flexible packet aggregation and grooming at 10/100/1000 Ethernet, allowing 10 GigE LAN traffic trunks.
  • Applications for testbed operation (Operation software): ADRENALINE Network Configurator (ADNETCONF) and ADRENALINE Network Generator (ADNETGEN) are advanced and adapted software applications and tools to allow the rapid operation and maintenance of the testbed, including common tasks such as the configuration and parameterization of the network topology, the generation of client requests modelling the behaviour of network customers, or the monitoring, data-mining and statistical processing of obtained results, allowing researchers to obtain numerical performance data and to perform experimental research and quantitative comparative analysis.
  • DSP-enabled software defined optical transmission (SDOT): digital signal processing (DSP) has been adopted as a key methodology to develop optical transceivers than can be dynamically adapted to different modulation formats and/or bandwidth occupancies. This technology is referred to as DSP-enabled SDOT. Within ADRENALINE framework, off-line DSP performed at both the transmitter and receiver subsystems is based on MATLAB software. The generated scripts contain the necessary functions in order to implement the different blocks involved: serialization/parallelization, generation of the desired modulation format, up/down conversion to an intermediate RF (e.g., for variable guard band generation), synchronization, equalization, demapping, etc. Because of SDOT reconfigurability, optimization techniques as non-uniform bit/power loading can also be implemented for the transceivers.
  • Optical OFDM systems (O-OFDM): Optical Orthogonal Frequency Division Multiplexing (O-OFDM) is a promising technology for future optical networks, thanks to its robustness against transmission impairments, its spectral efficiency and its unique flexibility and scalability to high-speed transmission. OFDM-based transceivers can be adapted to different modulation formats and bit/power loading schemes, while achieving subwavelength granularity. Among the different O-OFDM techniques, those based on intensity modulation and direct detection (IM/DD) constitute a cost-effective solution. Coherent (CO) OFDM schemes have been investigated (but not yet implemented) in order to enhance the spectral efficiency, the attainable distance, and to support higher bit rate (up to 100 Gb/s). In ADRENALINE, transceivers are implemented using either the fast Fourier transform (FFT) or the fast Hartley transform (FHT). In FHT-based O-OFDM systems, low-complex DSP is used, where only real algebra and M-PAM format are required.
  • Bandwidth variable transponders for Elastic Optical Networks (BVT): The bandwidth variable transponder (BVT) is a key element of an Elastic Optical Network (EON). The ability of generating elastic optical paths is enabled by its flexibility in terms of variable parameters/attributes, such as the modulation format, the data rate, the number of carriers and the bandwidth occupancy. Software-defined BVTs allow reconfiguring the transmission scheme with a suitable selection of these flexible parameters, for an optimal resource usage in a flexgrid network. ADRENALINE roadmap includes future developments of elastic and sliceable transponders (S-BVT), now under investigation. Recently, several devices and equipment have been acquired in order to start the implementation of these transponders (e.g., programmable optical filter based on LCoS technology).

The right combination of the technologies above described, always within the framework of the ADRENALINE testbed, enables the flexible deployment of different demonstration platforms. For example, the Cloud Computing Platform of the ADRENALINE testbed includes a SDN IT and Network Orchestrator, several data-centre IT infrastructure servers, SDN controllers for intra-data centre networks and inter-DC connectivity through a GMPLS/PCE-controlled WSON.

A Control Plane Emulator uses a subset of GMPLS controllers form the pool of available servers to test advanced multi-domain and multi-layer scenarios, with in-house developed GMPLS and PCE protocol stacks. The platform includes a web based interface and enables the uploading of PCE algorithms using an open-API for remote (third-party) operation, and the interconnection with third-party is enabled by IPsec tunnels. Applications for testbed operation (Operation software) are exploited for dynamic configuration of networks and generation of user-defined traffic patterns and performance analysis.

The GMPLS-controlled WSON demonstrator deploys WSON, GMPLS, PCE and Operation software technologies for a data plane with a single layer, whereas the Multi-layer GMPLS-controlled MPLS-TP/WSON represents a dual layer transport network based on all technologies included in the platforms above mentioned, adding the MPLS-TP/PWE3 nodes. Considering also the Virtualization in both cases of single or dual layer data plane, these other platforms can be deployed: Virtual GMPLS-controlled WSON and Virtual GMPLS-controlled MPLS-TP over a shared WSON demonstrators. The OpenFlow-controlled WSON platform uses the OF controller instead of the GMPLS control plane.

The last example of platform that can be deployed so far is the Experimental Platform for Optical OFDM Systems (EOS). Up to now, the combination of SDOT, O-OFDM and (S)-BVT technologies enables the design and assessment of flexible, power-efficient and cost-effective DD transmission. Both an arbitrary waveform generator at the transmitter side and a real-time oscilloscope at the receiver incorporate SDOT technology for the generation/sampling/processing of the electrical signal. Several optoelectronic and electronic components (e.g., modulators, photo-detectors, amplifiers, fiber-optic spools, etc.) allow the conversion between electrical/optical domains, and the transmission performance testing. Finally, several components and equipment are being acquired in order to upgrade EOS platform with the implementation of CO schemes. The intensity modulator will be replaced by an IQ optical modulator, and the DD receiver of the optical test-bed will be substituted by a CO one (including local laser, optical hybrid and array of balanced detectors).