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SFC Service Function Path Optimization (Offloads) draft-kumar-sfc-sfp-optimization-01. Surendra Kumar Jim Guichard Paul Quinn Cisco Systems, Inc. Joel Halpern Ericsson. Core Argument Optimize the Service Function Path. Traffic need not traverse all the SFs, all the time
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SFC Service Function Path Optimization (Offloads)draft-kumar-sfc-sfp-optimization-01 Surendra Kumar Jim Guichard Paul Quinn Cisco Systems, Inc. Joel Halpern Ericsson IETF 91, Honolulu | SFC WG
Core ArgumentOptimize the Service Function Path • Traffic need not traverse all the SFs, all the time • Higher latencies: network, SF processing, etc. • Wasted resources: network, memory, cpu, etc. • Alter the SFP, in the data-plane and within policy • SFs control this, while being agnostic to SFP • SFP shortens while SFC remains un-altered! • Use SFC Encapsulation to optimize the SFP IETF 91, Honolulu | SFC WG
SFP Optimization MethodSimple Offloads in two stages • Simple Offloads • ‘Offload’ directive (Yes or No) + ‘Action’ (Permit or Deny) • Stage1: SF Offloads • SFs request SFFs to not steer further packets on a flow • Stage2: SFF Offload propagation • SFFs propagate offload directives upstream to other SFFs IETF 91, Honolulu | SFC WG
SFC ArchitectureExample diagram with workloads and SFs • Service Function Types: • SFa • SFb • SFc SFC Control Plane Service Overlay IETF 91, Honolulu | SFC WG Transport Underlay SFF4 SFF3 SFF5 SFF1 SFF2 NF NF NF NF NF WL1 WL2 WL3 WL4 WL5 WL6 SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Work Loads Service Functions Work Loads
SFC Architecture …2Example diagram with workloads, SFs, SFC and SFP SFC :: {SFa, SFb, SFc} SFP :: {SFa1, SFb1, SFc1} SFC Control Plane Service Overlay IETF 91, Honolulu | SFC WG Transport Underlay SFF5 SFF4 SFF1 SFF2 SFF3 NF NF NF NF NF WL1 WL2 WL3 WL4 WL5 WL6 SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Work Loads Service Functions Work Loads
Simple Offloads, Stage1SFs offload service delivery to SFFs, at flow granularity SFC :: {SFa, SFb, SFc} • SFP :: {SFa1, SFb1, SFc1} • SFb1 is offloaded to SFF3 Cache Offload decision SFC Control Plane offload Service Overlay IETF 91, Honolulu | SFC WG Transport Underlay SFF2 SFF1 SFF3 SFF4 SFF5 NF NF NF NF NF WL1 WL2 WL3 WL4 WL5 WL6 SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Work Loads Service Functions Work Loads
Simple Offloads, Stage1 …2SFs offload service delivery to SFFs, at flow granularity SFC :: {SFa, SFb, SFc} • SFP :: {SFa1, SFb1, SFc1} • SFb1 is offloaded to SFF3 • SFa1 is offloaded to SFF2 • SFc1 is offloaded to SFF4 Cache Offload decision SFC Control Plane Offload Offload Service Overlay IETF 91, Honolulu | SFC WG Transport Underlay SFF5 SFF2 SFF4 SFF1 SFF3 NF NF NF NF NF WL1 WL2 WL3 WL4 WL5 WL6 SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Work Loads Service Functions Work Loads
Simple Offloads, Stage2Optimum SFP Offload SFC :: {SFa, SFb, SFc} • SFP :: {SFa1, SFb1, SFc1} • Offloads propagated towards the classifier • SFF1 directly forwards on the underlay SFC Control Plane Service Overlay IETF 91, Honolulu | SFC WG Transport Underlay SFF1 SFF3 SFF4 SFF2 SFF5 NF NF NF NF NF WL1 WL2 WL3 WL4 WL5 WL6 SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Work Loads Service Functions Work Loads
Simple Offloads, Key BenefitDistributed SF delivery Service overlay and SF sharing across SFFs & SFCs, leads to distributed SF delivery effect Service Overlay SFF1 SFF2 SFF3 SFF4 SFF5 Transport Underlay SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Service Functions IETF 91, Honolulu | SFC WG
Why not classify and bypass SFs, instead ?Achieve similar effect through SFC Classifiers or Control Plane • Classify & select appropriate chain @ SFF • Static classification • SF classification vs. SFF classification • Classification overhead • Use Control Plane • Too slow • Buffer or Drop traffic ? • May be appropriate in some cases SFC Control Plane Service Overlay IETF 91, Honolulu | SFC WG Transport Underlay SFF SFF SFF SFF SFF NF NF NF NF NF WL1 WL2 WL3 WL4 WL5 WL6 SFa1 SFa 2 SFa 3 SFb 1 SFb 2 SFb 3 SFc 1 SFc 2 SFc 3 Work Loads Service Functions Work Loads
What next ? • Allocate necessary bits in SFC encapsulation • Just two for simple offloads • 1-bit: Offload, 1-bit: Action • Enables SFF & SF simple-offloads interoperability • Reference this in the SFC architecture draft • Adopt as a WG draft • Please provide feedback/comments IETF 91, Honolulu | SFC WG