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Network Based Services in Mobile Networks Context, Typical Use Cases, Problem Area, Requirements. IETF 87 Berlin, 29 July 2013 BoF Meeting on Network Service Chaining (NSC) walter.haeffner@vodafone.com n.leymann@telekom.de.
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Network Based Services in Mobile NetworksContext, Typical Use Cases, Problem Area, Requirements IETF 87 Berlin, 29 July 2013 BoF Meeting on Network Service Chaining (NSC) walter.haeffner@vodafone.com n.leymann@telekom.de IETF 87 - 29 July 2013
Context: Mobile Networks and Service PlatformsMajor Building Blocks of a LTE Service Platform LTE Control Plane HSS Home Subscriber System Policy& ChargingRulesFunction LTE Data Plane PDN: Packet Data Network MME PCRF Mobility Management Entity OperatorBased Services NetworkServices(SGi-LAN) SGi eNB Cell AggregationNetwork Backhaul Network S-GW P-GW eNodeB Internet ServingGateway PacketGateway • SG-interface is the 3GPP reference point between P-GW and Packet Data Network. • SGi protocol structure, data content, scope not specified (equal for Gi in 3G networks). • Operator based services like, VoLTE, Mail, Web, RCS-e/Joyn, SMS, MMS not in scope. • Scope here: network services like firewalls, DPI, performance enhancement proxiesfor videos, TCP optimization & header enrichment, NAT, load balancers, caching, etc. • This class of services takes care of managing network traffic and network policing. IETF 87 - 29 July 2013
Context: Principle of Typical Hard-Wired SGi-LAN ServicesCurrent Common Approach – Logical View on Typical Use Cases Web Service for Smartphone User P-GW @ LB WebProxy FW NAT APN Fixed-Mobile-Converged Enterprise Service Mobile Access RouterACL APN MPLS VPN Operator’s IMS offer Operator’s IMS (VoLTE) SBC APN Video Service APN: Access Point Name LB: Load BalancerFW: FirewallACL: Access Control List SBC: Session Boarder ControllerIMS: IP Multimedia SubsystemOTT: Over The Top OTT Video Service Video Optimizer FW APN Service related IP interface, VLAN IETF 87 - 29 July 2013
Problem: Hard-Wired SGi-LAN ServicesCurrent Common Approach – More Physical View on Typical SGi-LAN GWRouter PE Router to IMS to Internet IP BB TCP Optimizer HTTPOptimizer PE Router Router Performance EnhancementProxy (PEP) DPI LB/NAT Caches InternetFW/NAT RoamingFW Video Optimizer HTTPProxies • With deployment of additional value-added services increasing number of functions required in SGi-LAN. Some functions in dedicated devices, sometimes multiple functions in one box. • Due to fast service introduction cycles service chains emerge, growth & change evolutionary. • Very often static IP links, policy routing, VRFs etc. used to enforce required service sequence. • Results in steadily increasing, handcrafted complexity and decreased visibility of functional dependencies between service chains and underlying LAN topology. Means expensive OAM. • Practically impossible to implement automated service provisioning and delivery platform. SGi P-GW IETF 87 - 29 July 2013
Requirement: Simplicity, Flexibility, Speed, ExpandabilityVision: Service Chain Abstraction and Network Compilation • Create Service Function Topology • Define Branch Conditions graphs uni- orbidirectional 4 1 2 6 Compiler not yet invented creates Configuration for Service Chains Abstract service 1 3 5 Abstract link S1 (virtual) service engine Mediation Device (virtual) forwarding device S4 S1 S5 S2 S6 S3 • Preference for Telco Cloud • Forwarding Topologies for multiple service chains • Branching rules in services Physical Layer IETF 87 - 29 July 2013
Requirement: High Degree of Freedom in Chain CreationNetwork provides us with sufficient Metadata to differentiate Some metadata in P-GW state UE: terminal type (HTC one) IMSI (country, carrier, user) GTP Tunnel: eNB-ID time PCRF: user APN (service) QoS policy PCRF Gx P-GW PEP Load Probe GTP Tunnel SGi User Equipment (UE) Probes may deliver cell load,link loads, session loads etc. for real time network policing BGP-TE/LS • We may connect all relevant service functions with all relevant sources for metadata or • We may piggyback metadata information with the IP packets traversing a service chain. • Piggybacking metadata seems to be more straightforward than picking them out with DPI. IETF 87 - 29 July 2013
Summary: • Market dynamics accelerate need and demand for more services at an even faster rate. • With current approaches network service LANs and their service chains become more and more complex, error-prone, hard to manage and hard to extend. It’s a dead end street. • Vision is to decouple creation of service topologies and their internal branching conditions from the creation of the associated underlying packet forwarding (overlay) network. • Operators think in terms of an ordered sequences of network services (more precisely graphs) selected out of a service pool and define forking conditions in the service graphs based on metadata sets including user data, related service classes, type of user equipment in use, network conditions etc. • (Conditional) forwarding decisions done in a network service node may allow for more real time flexibility than more static service topology paths in an underlying network. • We would appreciate if IETF agrees to start a WG on Network Service Chaining analyzing requirements and specifying solutions also supporting virtualized service environments. IETF 87 - 29 July 2013