SDN Overlays Possibilities and Implications

Transcription

1 SDN Overlays Possibilities and Implications Sharon Barkai Co-founder ConteXtream Santa Clara, CA USA April-May 2014

2 Agenda Coupling network services with bridging-routing, subnets-interfaces Complexity, fragmentation, and scale pressures created SDN decoupling and inline orchestration of network services Limitations of SDN without structure Mitigation by SDN overlay structure 3 use cases of inline flow orchestration 2

3 Coupling Functions and Routing Re-Aggregation, Rails of Permutations Fragmentation, Design for Peak Lots of Special hardware 3

4 SDN-OpenFlow.. A Start Innovative dynamic Control without compromising performance-density Subscriber Application Network Aware Services Decoupled from Subnets & Hardware Interfaces 4

5 Challenge 1: Non-Polynomial (NP) Hops Src > B > Switch <> F(x) > A > Dst = Best! But A might fail, best pre-prepare alt. But then so might B, or D Controller Add a Switch or Function? Xtrapolate DST A F(x) B SRC Xtrapolate D C 5

6 Challenge 2: Non Shared Fate (CAP) Distribution Controller???? DST <<Reachable Y/N <<Reachable Y/N <<Y/N Y/N >> Y/N >> <<Y/N F(x) <<Y/N Reachable Y/N >> << Reachable Y/N <<Y/N SRC?? P(topo inconsistent) >> 1 [Overlay!!!] Consistency, Availability, Partition (CAP) challenges Amplified by Loss of Autonomicity 6

7 Solution: Overlays Complete Virtualization Separate Control-Forwarding Separate Functions-Junctions Separate Identities-Locations Network Virtualization Overlays 7

8 Adding SDN Overlays Overlays Separate ID-Location and Scale By Underlay + Mapping Mapping by Hashing keys to IP/ Ethernet addresses EndPoint EndPoint (IP or Ethernet Addresses) IP or Ethernet Underlay EndPoint Landmark or Function (RTR, BGP,Firewall ) With Freedom of movement Autonomous Bridging & Routing is resorted in the underlay location network Underlay striped from apploication complexity orders of magnitude less addresses Local decision synced to local forwarding using global mapping awareness 8

9 Adding NVO Standards to SDN Location Identity Separation Protocol (RFC6830) Service Chains IP or Ethernet Additions in draft-lisp-sdn-nfv for LISP-NVO Support SDN: XTR mapping-caching based on Flows (5-Tuple), Mapping supports Pub-Sub using SMR Support NFV: Mapping is subscriber-affinity aware, flowhandlers protocol specific XTR, MANO- Mapping 9

10 Use Case 1: Collapsed Packet Core Mobile access traffic is aggregated using an IP network into data-centers for network function processing Processing can occur in multiple racks and also in multiple distribution-centers to balance loads Network functions are applied per subscriber-flow based on user profile, application and network conditions. Example functions: TCP window RAN optimization, Video transcoding, Filters and firewalls, Header enrichment, Analytics, Web proxy The SDN-NVO Fabric needs to map subscriber-flows to applications through functions by doing the following: Classify-map each flow at each re-entrant forwarding point Apply and maintain inner NVE flows per mapping lookup Maintain state affinity where flows stick to NFV instances 10

11 Use Case 1: Collapsed Packet Core (Gi, EPC,WAG,IMS,SBC..) AAA Subscriber Registration and Map- Instantiate Overlay & Mapping RAN PDN! Gateway Router Internet TCP opt Transcode H-Enrich 11

12 Use Case 2: Managed Network Service Classic managed network services: Multi-departmental, Multiapplication, Multi-tenants connected across Multiple sites and branches While Multi-Netting was always supported by IP much more separated Virtual Private Networking was initially delivered by ATM- FRAME, and today delivered mostly using MPLS. Example: Virtual Routing Forwarding (VRF) in Provider Overlay Edges Label Switching Paths (LSP) configured across the underlay Current methodology is relatively static, changes to VRFs can destabilize route convergence and LSPs plant states on each hop This methodology is replaced by dynamic FlowMapping overlay edges, emulated if needed (MPLS LSP tags to untouched PEs) Downstream tags are classified as flows, mapped and encaped Decapsulated and re-tagged at the other end of the network 12

13 Use Case 2: Managed Network Service (MPLS-E, IP Transit, Backhaul) Map&Encap >> Dynamic MPLS Emulation Mapping 121.1:2: : : :2:7 SDN-Edge RSVP or LDP Overlay & Mapping SDN-Edge MPLS Port1 MPLS Port2 IP port IP port PE Location CE PE IP port IP port MPLS Port1 MPLS Port2 MPLS port3 IP port <<Tag7 <<Tag17 IP port MPLS Port3 13

14 Use Case 3: Distributed Packet Core Backhaul Collapsed Packet Core Signaling Segment Routing Landmark 2: Elephant flows Overlay & Mapping Segment Routing Landmark 1: Butterfly flows enb Locations IP Locations 14

15 SDN for NFVs How SDN Overlays support NFVs Small NFVs Enterprise class discrete VMs Like Gi filters, Transcoders Big NFVs Carrier class multi-vm systems Collapsed packet core EPC/IMS Integrated inline orchestration Forwarding Control Chaining each of the functions per each subscriber flow, Local and global load balancing of the micro instances, affinity protection from topology changes due to network conditions or VM mobility Emulate / abstract a switch for control software by tapping OpenFlow or the 3gpp control Global load balancing of cores, flat core sites for the statesharing middleware 15

16 Summary Examined limitation of tying network services to Layer 2/3 topology, and SDN to alleviate these Saw that unstructured SDN can have even greater scaleconsistency issues, can be solved by the standard structure of overlays: SDN OpenFlow should not cross routing locations SDN flows cross locations by "Map & Encap" Distribution is based purely by underlay & mapping Examined 3 use cases: collapsed mobile packet core data-center, managed network services, and mobile (human-machine) backhaul 16

17 Thank You North Bound Mapping Database NVE NVE IP NVE NVE Users < - - FlowMapping - - > Functions 17