Service Function Chaining in Mobile Networks

Status draft-haeffner-sfc-use-case-mobility IETF 89 London, 3 March 2014 Service Function Chaining WG Walter Haeffner [email protected]

, Jeff Napper Martin Stiemerling [email protected]

, Diego R. Lopez [email protected]

[email protected]

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acknowledgement We thank

Linda Dunbar Ron Parker Wim Hendericks Alla Goldner Dave Dolson Peter Bosch Praveen Muley Carlos Correia, ...... for valuable comments IETF 89 - London, UK - 3 March 2014 2

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1 – context Mobile network operators need to implement a complex array of single- (or few-) function devices

( a.k.a. SFC)

to control data traffic such that they can achieve their business goals.

per user policy and charging enforcement PCRF

3GPP Mobile Network

P-GW

caches > SFC <

DC Appl.

• IPTV • eMail • VoIP @ Appl.

• YouTube • bing • iTunes

protect network & privacy

– FW, IDS, ACL, ...

optimize transport & payload

– TCP Opt., Video Opt., ...

functions required for technical reasons

– GC-NAT, DPI, LB, ...

merge signaling information into data flow

- HTTP header enrichment, ...

network-based value added services

– parental control, malware protection, ...

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2 - objectives

     Understand importance of Service Function Chaining for mobile network operators - Influence to their business Discuss Service Function Chains (SFC) in the context of mobile network architectures – exemplary state of the art use cases Work out potential weaknesses in current environments and derive operator requirements to support SFC WG objectives Compare with activities of other standard bodies, especially clarify interaction between 3GPP and IETF SFC approach A possible dream SFC environment from an operator’s point of view based on NFV, SDN, reflecting abstraction levels ....

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3 – status draft

 

Draft-00 issued 29 Jan. 2014

 Service chains supplement 3GPP policy and charging control architecture  PCC and SFCs play a significant role in mobile service specifications  SFCs often a sequence of “little” proprietary SFC implementations  Therefore typically a hierarchy of inspections & classifications in place    Discussed weakness of current solutions and requirements to SFC WGs

Draft-01 issued 14 Feb. 2014

 Sketched use case “video optimization” (L7) and “TCP optimization” (L4) Added 3GPP R11 Traffic Detection Function (TDF) [3GPP TS.23.203]  Discussed simple classification and flow steering schemes Allows for fine grained classification schemes and feedback to PCC IETF 89 - London, UK - 3 March 2014 5

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3 – status draft - basics of a video optimization SFC

Functional view of a model video optimizer SFC e.g. VoIP classified “video” Cache P-GW LB Crtl DPI Video Video Opt.

“port 80 no video” LB FW NAT classified “port 80” “non-port 80” classified “web service” Draft-00 & draft-01 shows flow steering based on HTTP redirections @ IETF 89 - London, UK - 3 March 2014 6

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4 – outlook draft-02 to be published end of March

Discuss impact of re-classification and chains of value added services.

move Load 4G (LTE) 3G (UMTS) PCRF GW RAT

Video SFC

Action/Forwarding based on NW Load RAT = 4G : opt .off

RAT = 3G : opt. on

Malware Prevention

@

DPI

VAS Port 80 @ IETF 89 - London, UK - 3 March 2014 7

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5 – outlook draft-02 to be published end of March

Grown multi-vendor structures may become very complex, inefficient, hard to understand and hard to manage PCRF P-GW Web APN

LB DPI Analytics vendor a

Web APN re-classify RAT

Video Opt.

Malware Prev.

LB DPI Parental Control

classified port 80

CRTL DPI

classified video

Video Cache

classified port 80, non-video Web APN

LB FW NAT

classified non-port 80

TCP Opt.

@

does not reflect wiring and actual packet flow!

vendor b vendor c

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5 – Weaknesses and Requirements Weaknesses in current deployments

 Per APN service chaining, in almost any case classification too coarse grained  Means traffic often unnecessarily traverses a service function, no offloading  Often ad hoc sequence of individual mini-chains, each with its own classification  Results in multiple, individual DPI inspection systems, multiple LB batteries  Is expensive, complex, inflexible, hard to modify/extend with reduced performance

Possible solutions

 Mobile network MUST exchange context with the IETF SFC classifier function  SFC classifier MUST tag packets such that these enter only the SFs required  Means bi- and unidirectional flows MUST be allowed  Individual SFs MUST participate in multiple, different SFCs  Creation/modification of SFCs including their branching rules SHOULD be done in a simple to use SFC editor. Mapping onto the underlay MUST then be automatic.

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6 – IETF SFC interactions with 3GPP PCC architecture

How to exchange 3GPP user & control plane metadata with IETF SFC?

Subscription Profile Repository

Sp

PCRF

Gxx

Application Functions

Rx

Gx BBERF Access Network Gateway PCEF P-GW

Sy

Online Charging System

Gy

Sd TDF [DPI] “3GPP Classifier” Metadata Exchange ?

IF ?

IETF SFC-1 IETF SFC Classifier IETF SFC-n

3GPP PCC

Offline Charging System

BBERF: Bearer Binding and Event Reporting Function IETF 89 - London, UK - 3 March 2014 IETF SFC 10

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7 – outlook draft-IETF 90

  Isolate input to requirements and functional specifications.

 Listed all use case classes required to verify universality of SFC WG architecture and design paradigms for mobile.

SFCs for fixed networks (xDSL, Cable) are typically a subset of what is seen in mobile. List synergies w.r.t. FMC scenarios.

 Analyse requirements for the interaction between the 3GPP and the IETF SFC classification schemes.

 Initiate a discussion to clarify how to proceed in case of encrypted traffic (IETF 88 resolution).

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