Scenarios, Niches, Architectures Special Topic: Software Defined Networks Rudra Dutta Computer Science, NCSU

SDN Picture A new(-ish) paradigm, a general technique: Create open, standardized, remote access interfaces to settings that did not previously have such interfaces Can use software (agile) to access these interfaces Forwarding engine can perform standard forwarding functionality efficiently (perhaps hardware) Separation of policy and mechanism (into boxes) For achieving goals and characteristics: Apply network-level (e.g. routing) policies at fine-grain Mixing-and-matching forwarding elements, policy elements, other service elements (e.g. monitoring) Isolate and provide predictable performance for fine-grain customer traffic elements Do all of the above in agile, non-disruptive manner Copyright Rudra Dutta, NCSU, Spring 2017

Architecture, Common or Not To realize above visions, may be necessary to create standardized interfaces So that separate architectural entities can be separate And be mixed-and-matched Conversely, absence of architectural interfaces defined / standardized can discourage open interchangeable / interoperable elements Essentially fragments architecture, creates multiple competing architectural silos Copyright Rudra Dutta, NCSU, Spring 2017

Entity Aggregation Entities represent roles that different stakeholders (with different interests) can play Inter-entity interactions requires interface that both (all) agree on  standardized protocol / open interface If one entity performs multiple (standardized) roles, it must realize every standardized interface at “external” edges, but may ignore standardized interfaces at “internal” edges Copyright Spring 2017, Rudra Dutta, NCSU

Entity Aggregation Entities represent roles that different stakeholders (with different interests) can play Inter-entity interactions requires interface that both (all) agree on  standardized protocol / open interface If one entity performs multiple (standardized) roles, it must realize every standardized interface at “external” edges, but may ignore standardized interfaces at “internal” edges Copyright Spring 2017, Rudra Dutta, NCSU

Open Interfaces vs. Closed Silos An entity may attempt to maintain external standard interfaces, while speaking proprietary value-added interfaces Faster/better growth of efficient proprietary interfaces  silo’d solutions Common architecture allows mixing-and-matching, but requires (larger number of) standardized interfaces Copyright Spring 2017, Rudra Dutta, NCSU

Open Interfaces vs. Closed Silos An entity may attempt to maintain external standard interfaces, while speaking proprietary value-added interfaces Faster/better growth of efficient proprietary interfaces  silo’d solutions Common architecture allows mixing-and-matching, but requires (larger number of) standardized interfaces Copyright Spring 2017, Rudra Dutta, NCSU

Open Interfaces vs. Closed Silos An entity may attempt to maintain external standard interfaces, while speaking proprietary value-added interfaces Faster/better growth of efficient proprietary interfaces  silo’d solutions Common architecture allows mixing-and-matching, but requires (larger number of) standardized interfaces Copyright Spring 2017, Rudra Dutta, NCSU

Architectural Requirement Open management interfaces Not just a question of an open standard protocol for NE  NMS communication Requires a “language” or at least “vocabulary” SNMP Adopts ASN.1 (subset) Talking about network concepts of importance Another component of architecture Question: What should a common, inclusive architecture for SDN look like? Components? Entities? Interactions? No broadly accepted “reference architecture” Form follows function  examine usecases Copyright Rudra Dutta, NCSU, Spring 2017

Characterizing Usecases / Solutions Variety of achievable network-level policies Variety/heterogeneity of NE capabilities integrated Efficiency of forwarding Independent usefulness of coordinated elements Multiple strength dimensions Different usecases/solutions require/offer different mix Architecture should enable all Copyright Rudra Dutta, NCSU, Spring 2017