Challenges of Service Provisioning in MPLS OpenFlow Dávid JOCHA, András KERN, Zoltán Lajos KIS, Attila TAKÁCS Ericsson Research Hungary WTC 2012 SDN Workshop
SPARC Semi-Centralized Control for Carrier-Grade Aggregation SPARC aims carrier grade split architectures • With focus on operators’ networks • OpenFlow as split architecture enabler • NNI Legacy Distributed control Centralized control Intelligence OSPF, LDP Control Entity RSVP-TE, BGP UNI IGMP MPLS MPLS CP CP Control Protocols Video OF OF OF OF Core Core Client Edge Switch Switch Switch MPLS MPLS MPLS CP Control Protocols WEB basic forwarding OF OF OF Core Client functions Edge Switch Switch MPLS Services Clients OPENFLOW MPLS Aggregation IP/MPLS core Split control (OpenFlow-MPLS) in acc/agg, interworking with legacy IP/MPLS core
Heterogeneous Services on top of a Homogenous Transport Vast number of services • – Different characteristics, service specific control – Service mix can change frequently and rapidly NNI Legacy Distributed control Centralized control Intelligence OSPF, LDP Control Entity RSVP-TE, BGP UNI IGMP MPLS MPLS CP CP Control Protocols Video OF OF OF OF Core Core Client Edge Switch Switch Switch MPLS MPLS MPLS CP Control Protocols WEB basic forwarding OF OF OF Core Client functions Edge Switch Switch MPLS Clients Services OPENFLOW MPLS Aggregation IP/MPLS core
SPARC control framework Generic controller Adapted to our Use-case framework IPTV Residential Business LAN Internet access CTRL CTRL CTRL Control layer (n+1) Users Channels Endpoints DHCP Users Multicast logic OAM module DP Service Service Service Control layer (n) Controller Controller Controller CTRL DP DP DP Control layer (n-1) Transport Visor Transport Visor Transport Visor Transport Resource Visor NNI Protocols End-to-End Tunnel Management vRIB OSPF, LDP, RSVP-TE Hierarchical controller structure • Aggregation Domain Interface – Layered control plane, Topology Flow Mapper Tunnel Management management DB Transport interworking with eachother OpenFlow controller kernel Controller Recursive Stacking – – Interfaces
Service example 1: Virtual Private LAN Service (VPLS) Virtualized view of the network VPLS Controller OF Switch Transport Controller Legend: Client Client OF OF OF OF Edge Switch Switch Switch Service MPLS tunnel Transport MPLS tunnel Client OF OF OF1.0 MPLS Edge Switch or OF 1.1 Transport and service are the two mayor layers
Service Example 2: Residential Service with BRAS MPLS OpenFlow Controller Broadband Remote Access • Residential Service APP Server (BRAS) functions include: AAA – L2 VPN Control APP L3 VPN Control APP – PPP termination MPLS Transport Application NOX kernel BRAS Legend: Video L3 MPLS VPN tunnel Client OF OF OF OF aka IP-MPLS-MPLS Edge Switch Switch Switch L2 VPN tunnel aka ETH-PW-MPLS WEB Transport MPLS tunnel Client OF OF OF1.0 MPLS Edge Switch or OF 1.1 L2 and L3 type tunnels contribute to the same (higher layer) service
What is missing in standard OpenFlow? L2 connectivity PWE (E-TREE) End-to-End MPLS OF Internal MPLS Data plane OF OF OF core VLC SE OF MPLS MPLS MPLS MPLS server layers • Flexible encapsulation needed – L3 in L2: supported – L2 in L3, L2 in L2: not supported – L2/L3 connectivity on the top of MPLS Pseudowire (PWE) • Stateful processing at endpoints – Per packet processing in controller does not scale
OpenFlow protocol extension: Stateful processing and endpoints • Packet processor – Extending the datapath functionality with stateless and stateful packet processing, backward compatible – Examples: PW, LLDP, Meters, IPv4 defragmentation, BFD, … Flow Flow Table Processor Table Flow Flow Flow Processor Flow Processor Processor Port Flow Flow Flow Flow Processor Group Flow Processor
OpenFlow protocol extension: Pseudowires Generic PWE3 over • To be supported PWE3 MPLS – Bottom of stack bit support Payload (match, set) Payload Payload Conv. – Push/Pop labels/GALS/G- Encapsulation Timing RTP Sequencing Ach header/control word PW Demultiplexer Control Word before Layer 2 Flags, Frag, Len, Seg# – Ability to POP labels and PSN Convergence PW Label figure out data type Outer MPLS Label PSN underneath it Data-Link Data-Link – Ability to process control word and G-Ach header for Physical Physical OAM etc
Example: PW Implementation (with BFD) TCP BFD TCP BFD IP UDP IP UDP BFD ETH IP ETH IP TCP UDP CV VCCV CV VCCV IP IP MPLS (PW) MPLS (PW) User traffic ETH ETH MPLS (LSP) PW MPLS +metadata ETH Flow Ingress TCP Flow Table Table IP VCCV (IPv4 pkts) ETH Group Flow Flow Port Flow Port BFD Flow Flow Port Flow Port Flow Flow Flow Flow VCCV (IPv4 pkts) TCP PW MPLS IP Egress TCP BFD TCP BFD ETH IP UDP BFD User traffic IP UDP ETH IP UDP ETH IP TCP CV VCCV IP CV VCCV IP MPLS (PW) MPLS (PW) ETH MPLS (LSP) ETH ETH +metadata
Outlook • Management aspects – OAM – Network Management System • QoS – OpenFlow support • Other encapsulation modes – PBB – GRE
Thank you for your attention!
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