Various Alternatives to achieve SDN Dhruv Dhody, Sr. System Architect, Huawei Technologies
Who? India R&D Huawei Dhruv Dhody • A multinational • First and biggest R&D • 11+ years in Huawei networking and center outside of China. (Bangalore, Beijing, telecommunications Santa Clara) • High end equipment and services communication • Network OS dept with company headquartered software specialization in Traffic in Shenzhen. platforms/components/ Engineering and Path • We are the largest applications. Computation telecommunications • Over 2600 engineers. • Lead a Research, equipment maker in the Standards & Prototypes world. team • Over 140,000 • 3 RFC / 8 WG employees and 21 R&D documents / 13 Patents institutes.
SDN, Lets Recap!
Why SDN? Computing Trends are Driving Network Change The Changing traffic The rise of cloud “Big data” means “ consumerization patterns services more bandwidth of IT” (BYOD) Limit Lim itation of of Curr rrent Networks Complexity that leads to Inability to scale Vendor dependence stasis • Add/Move devices • Link oversubscription to • Lengthy vendor equipment provision scalability product cycles • Implementing network wide policy • Lack of standard, open interfaces • Time consuming & Manual • Prone to errors
Software-defined networking (SDN) is an approach to computer networking that allows network administrators to manage network services through abstraction of lower-level functionality.
Dynamic SDN - Definition Manageable The physical separation of the network control Cost Effective plane from the forwarding plane, and where a Adaptable control plane controls several devices. Open standards- based and vendor- Programmatically neutral : When Centrally configured : SDN implemented Directly Agile : Abstracting managed : lets network through open programmable : control from Network standards, SDN managers Network control is forwarding lets intelligence is configure, simplifies network directly administrators (logically) manage, secure, design and centralized in programmable dynamically adjust and optimize operation because because it is network-wide software-based network resources instructions are decoupled from traffic flow to SDN controllers very quickly via provided by SDN forwarding meet changing that maintain a dynamic, controllers instead functions. needs. global view of the automated SDN of multiple, network. programs. vendor-specific devices and protocols.
SDN Applications • Programmatically SDN @ ONF communicate via NBI SDN Controller • Abstract view of network • Controlling SDN Datapaths SDN Datapath • Network Device SDN CDPI • Programmatic Control • Capability and reporting • Events SDN NBIs • Provide abstract network views • Direct expression of network behavior (intent)
Multi-Layer SDN SDN's logically centralized network Ex. If bandwidth at a particular layer Today, a service is typically intelligence and ability to leverage is exhausted in some portion of the transported at a single layer. With cloud computing for almost network, multi-layer SDN can multi-layer SDN, a network can unlimited compute power enables evaluate options and dynamically transport services over the most it to evaluate all layers of the add bandwidth from a lower layer efficient technology, not just the network concurrently to determine or reroute traffic from upper layers predefined transport technology. where best to send traffic.. around the point of congestion.
E2E SDN Orchestration of E2E service delivery across all network domains Distributed control planes with multiple cooperating controllers • ƒ EWBI (east-west) for controller to controller communications across domains • Enhanced SBI for support of specific network technologies and types • Enhanced NBI for support of customer/network applications Network virtualization and control capability Cross layer coordination (e.g., IP routing + Optical Transport)
SDN – Alternatives (looking beyond OpenFlow) PCE ALTO I2RS ACTN SR
PCE – Path Computation Element PCE is an entity that is capable of computing a network path or route based on a network graph and applying computational constraints Specializes in complex path computation across various domains on behalf of its path computation client (PCC) with enhanced scalability. Stateless PCE provides mechanisms to perform path computations in response to PCC requests. • It utilize only the TE link information database to do this computation (TEDB). Stateful PCE: Along with network state (TEDB), it also stores the state of all the computed paths or LSPs and their resources (LSPDB). • Enhanced algorithms at stateful PCE PCE-Initiated : Setup, maintenance and teardown of PCE-initiated LSPs from a central PCE server.
Stateful PCE Abstraction & Algorithms over Stateful PCE Stateful PCE Server Stateful PCE as evolutionary approach to SDN . PCEP In SP network with existing investment in Protocol IP/MPLS devices, active stateful PCE can offer centralized control over the LSPs as a simple evolutionary approach for SDN. PCC PCC
Stateful PCE OF-Based Stateful SDN PCE Only software update for New protocol - OF edge router (PCC). Continue to use existing New hardware might be signaling mechanism (RSVP) needed or use segment routing (SR) Opens up the control of data PCE Server acts as the SDN flows to customizable controller. software. PCE capable to compute, Controlling devices using a initiate, control and central orchestrator maintain the LSP.
ALTO – Application-Layer Traffic Optimization Extension to ALTO are proposed for Protocol provides Abstract simple mechanism Application can network to provide basic, topology graph make use of this abstract but useful information to use network network efficiently. Traffic information to Engineering applications. Service aware Usecases parameters This protocol • Peer to Peer File sharing developed on top • CDN of existing HTTP Calendering • Real-time (REST-ful) using Communication JSON • Live media streaming …
Application Stratum PCE+ALTO for Data DC 2 DC 4 DC 5 DC 1 DC 3 Centre Interconnect NET Arbiter + PCE ALTO Cross Stratum Optimization (CSO) - APP Arbiter Arbitration Optimization of Datacenter and Network Layer resources - which can only be achieved via PCEP joint effort & information exchange - to cross optimize between stratums. Network Stratum • Application DC resources Optimization • Network resource Optimization ALTO • Joint optimized DC application • Net-Arbiter uses stateful resources along with network PCE to query and obtain the resources. network status • Initially for P2P file sharing (torrents) • DC Migration, Schedule Backup, DC & CDN to get simple network cost & Network Events map • HTTP/Restful/JSON • ALTO extensions to support DC and PCE CSO network costs and events
Abstract Graph Abstract Application Controller Topology Network Controller Abstracted graph Access to an Abstract network topology, could allow an Application HYD to understand (User region) network in a much better way – find bottleneck, make dynamic decision with network BOM conditions in mind… DLI BLR (Data Center)
I2RS: Interface to Routing System SDN focuses on programming the data plane • Switch programming (cross-connects) • Forwarding (FIB) There are many functions and features not covered • Control of routers • Control of routing protocols •Management of the “routing system” Existing techniques are non-standard • Using CLI to achieve these functions is very frustrating • Expensive, time-consuming, error-prone, risky Need for a standard approach • Strong desire for a simple and standard approach
I2RS Usecases for I2RS Programming and managing the RIB BGP use cases Traffic steering and classification DDoS mitigation Topology reading, monitoring, and control I2RS to use Netconf/Restconf/Yang as the Service chaining base…
Netconf / Restconf / Yang Netconf Yang • Network • Data Model Management • Explicit precise Protocol structure, syntax • Remote primitives and semantics of to the (externally view/manipulate visible) data data • Think MIB Restconf • Encoding data as • Configuration data per the data model as well as state • A REST protocol over HTTP • Think SNMP • Also events • accessing data defined in YANG using • Transaction based datastores defined in NETCONF. (network wide) Netconf/Restconf/Yang as a base to manipulate state on the device!! (I2RS)
ACTN - Abstraction & Control of Transport Networks • Multi-layered multi-domain Network • Technology, administrative or vendor islands • Interoperability for dealing with different domains is a perpetual problem for operators. • New service introduction with connections that traverse multiple domains • Need significant planning • Manual operations to interface different vendor equipment and technology across IP and Optical layers. • Facilitate virtual network operations • Creation of a virtualized environment allowing operators to view and control multi-subnet multi-technology networks into a single virtualized network. • Accelerate rapid service deployment of new services • including more dynamic and elastic services • improve overall network operations and scaling of existing services. • Hierarchy of controllers
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