Service Function Chaining Use Cases
draft-liu-service-chaining-use-cases
IETF 88 Vancouver, 7 November 2013
BoF Meeting on Service Function Chaining (SFC)
Hongyu Li
Hongyu.li@huawei.com
IETF 88 – 7 November 2013
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Introduction
• Two use cases will be addressed, there are more
others
– (S)Gi-LAN
– NFV
IETF 88 – 7 November 2013
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(S)Gi-LAN
LTE Control Plane
Home Subscriber System
HSS
LTE Data Plane
Policy
& Charging
Rules
Function
PDN: Packet Data Network
Mobility Management Entity
MME
eNB
eNodeB
Cell
Aggregation
Network
Backhaul
Network
PCRF
S-GW
P-GW
Serving
Gateway
Packet
Gateway
Operator
Based
Services
SGi
Network
Services
(SGi-LAN)
Internet
Figure source: Network Based Services in Mobile Networks, IETF 87, Walter Haeffner
 SG-interface is the 3GPP reference point between P-GW and PDN, such interface is called G-interface in 3G
network
 PDN(Packet Data Network) includes Internet and operators’ service enablers, which reside in SGi-LAN
 Typical network services functions here includes: firewalls, DPI, video optimization, TCP optimization, HTTP
header enrichment, NAT, load balancers, caching, etc.
IETF 88 – 7 November 2013
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(S)Gi-LAN ctd.
DPI
Video
optimizer
NAT
SFC 1
PGW
user traffic
Traffic
Classifier
SFC 2
SFC 3
Switch/Router
normal forwarding/routing
user traffic
Internet
• A service function chain is a different path from normal forwarding or routing,
where traffic is steered according to service characters
• Traffic must be steered through service functions in a specific sequence
⁻ Service function chain1: default path
⁻ Service function chain2: http video traffic
⁻ Service function chain3: https
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(S)Gi-LAN ctd.
• Current common approach
– Hard-wired, static IP routing, policy routing etc. are used
– Continuously increase of manual configuration complexity
– Tightly coupled service function chain and underlying LAN
topology
• What are expected from operators
–
–
–
–
Automatic service provisioning
Simple, instant and flexible chain configuration
Expandable service functions and chains
Supporting virtualized service functions
IETF 88 – 7 November 2013
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NFV -- Virtualized Service Functions
Figure source: ETSI GS NFV 001, Network Functions Virtualisation (NFV) Use Cases
•
•
•
•
NFV requires chaining service functions (VNFs) in a certain sequence
Each colored line identifies a service function chain
SFC must be decoupled with underlining network topology, to support VM migration and inter-location deployment
One service function may be reused for different SFCs, where identifying each SFC coming from the same service
function by the forwarding plane is prerequisite
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Summary
• We presented two representative use cases to
illustrate the high level motivation for the work
– There are many more other use cases
• Propose to have a set of representative use cases
driving problem statement
IETF 88 – 7 November 2013
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