F5 Traffix: Diameter Routing Use

Cases for the Signaling Explosion

Barcelona, 24th May 2012

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• Introduction

• Problem description

• Use cases and solutions

• Summary

Agenda

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With data use at unprecedented levels due to smart phone

popularity and usage patterns, signaling in the LTE network

presents use cases never before experienced by operators.

Yes we all might have plenty of signaling experience…. but

how about Diameter signaling behavior??

Introduction

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What is the Fundamental Pain:

Explosive Mobile Data Growth

What is the pain? - Need to expand capacity but with much lower

revenues

- How to keep the costs well below the revenue line

Bring costs per Mb down: Launching of LTE networks (..trend towards All-IP)

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Why Diameter? Signaling Growth Predictions

• Smartphones, tablets

and mobile broadband

spread

• IP-based services

multiply

• Usage patterns change

• LTE

• Network architecture

changes and growth

• New trends increase

signaling load (M2M,

VoLTE, virtualization)

Data and Signaling Growth

So

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e: F

5 a

nd

va

rio

us s

eco

nd

ary

re

se

arc

h

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• SS7 signaling is much more voice/conversational services oriented, Diameter is mobility management AND database access oriented

• Initially much more mobility management due to LTE Islands

• Diameter is a session oriented peer-to-peer protocol and not like SS7 designed for networks, meaning things like:

• no dedicated management messages, failures ‘to discover’ with each new request, relies on reliable transport, no defined traffic priorities, etc.

• Customer and application + handset behavior much more unpredictable

• Unpredicatable when, where and how it will hit you...

• Massive smartphone signaling after “incidents”

What is SO different?!!

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LTE is happening now… 60+ networks launched

269 LTE

devices

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Meet the LTE Challenges • Element Connectivity

• How to design a scalable network architecture

• Many new network elements and traffic growth

• Message Normalization

• How to deal with different vendor’s Diameter implementations

• Load Balancing

• How to avoid careful planning per server

• How to protect against signaling spikes, signaling Tsunami

• Routing and Subscriber Guidance

• How to guide transactions toward specific servers

• How to manage network-wide routing and binding (like to PCRF, OCS)

• Roaming for LTE

• How to manage LTE - LTE global roaming

• How to manage LTE – 2G/3G interworking

• Topology Hiding

• How to hide network topology

• How to add clients and servers to the network without changing others

• Visibility into Diameter Control Plane

• How to view what’s going on

• How to test and simulate with minimal impact

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How to manage those differences and create new opportunities

• Use a load balancer (and smart router) in front of your billing systems and/or elements like HSS, PCRF

• Protect your network for high Diameter signaling loads to nodes like OCS, HSS, PCRFs

• Protect your Radius servers from smartphone generated signaling peaks

• Have a gateway between Diameter and LDAP, Radius, SS7-MAP and others

• Re-use existing investments and processes

• DRA, DEA, IWF for LTE networks

• Internal network

• Create a scalable architecture

• Manage signaling loads

• Roaming for LTE

• MVNO market

• IMS, more Diameter signaling

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Use Case: Diameter Router for Charging and DRA/DEA

Gx/Gy

S6a

HSS

MME

GGSN

PCRF

GGSN

MME

Gx/Gy

S6a

IPv4 SCTP

IPv4 TCP (could be IPv6,

IPsec, TLS, etc. as well

OCS

OCS pool 1

OCS

OCS pool 2

HSS

PCRF

Gy

Gy

S6a/S6d

Gx

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Key use cases:

- Routing between MME and HSS

- Routing & balancing to OCS (ongoing)

- Session binding (ongoing)

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How a PCRF is connected with a range of Diameter interfaces:

Policy Control Ready for the Next Wave

Gy

Gz

Subscription Profile

Repository (SPR)

Rx

AF Sp

Offline Charging System (OFCS)

Policy and Charging Rules Function

(H-PCRF)

Online Charging System (OCS)

Service Data

Flow Based Credit Control

Gxx

BBERF

Policy and Charging Rules Function

(V-PCRF)

S9

VPLMN

HPLMN

Gx

Gateway

Sd

TDF

PCEF

Sy

Source: 3GPP TS 23.203

AF= Application Function

BBERF= Bearer Binding & Event Reporting Function

TDF= Traffic Detection Function

PCEF= Policy & Charging Enforcement Function

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• (Over)load control or better flow control

• We limit load before OCS Or in other words: Never hit OCS load control mechanism with undesired

side effects

• Also applicable to other elements like HSS, PCRF, etc.

Use Case: Overload Protection

Overload control

by OCS

Flow control

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XXX Network Diagram Optimized

Charging System

Server 1

GGSN-1

Charging System

Server 2

GGSN-3

Charging System

Server 3

GGSN-5

Charging System

Server 4

GGSN-7

Charging System

Server 5

GGSN-9

GGSN-2

GGSN-4

GGSN-6

GGSN-8

GGSN-10

GGSN-11

Hmm, this is a mesh.. or mess

Charging System

Server 1.2 – active server

GGSN-1-1

.....

GGSN-1-8

Charging System

Server 1.1 – active server

Note: one server can handle 85%

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Charging System

Server 1

GGSN-1

Charging System

Server 2

GGSN-3

Charging System

Server 3

GGSN-5

Charging System

Server 4

GGSN-7

Charging System

Server 5

GGSN-9

GGSN-2

GGSN-4

GGSN-6

GGSN-8

GGSN-10

GGSN-11

Charging System

Server 1.2 – active server

GGSN-1-1

.....

GGSN-1-8

Charging System

Server 1.1 – active server

Note: one server can handle 85%

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Use Case: Contextual Routing

Routing Example based on IMSI

Maintains a database routing DB mapping between IMSIs and OCSs

IMSI is extracted from Subscription-Data Grouped AVP in CCR-I/AAR

IMSI Range:

1xyz-4xyz

IMSI Range:

5xyz-9yxz

CCR IMSI 55555 GGSN-1

GGSN-2

OCS

OCS pool 1

OCS

OCS pool 2 CCR IMSI 22222

CCR IMSI 11112

CCR IMSI 11112

CCR IMSI 22222

CCR IMSI 55555

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Use Case: Load Balancing

GGSN-1

GGSN-3

GGSN-2

Session 4

Session 5

OCS-2

OCS-1

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Use Case: Protocol Gateway

Diameter LDAP

HTTP

Diameter

PCRF Directory

Server

GGSN

Billing

Billing

Diameter MAP

MME HLR

Diameter, RADIUS, LDAP, SQL, HTTP, COPS, GTP’, Web-Services, JMS, MAP, CAMEL,

CORBA

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Use Case: LTE Roaming Guidelines

• Defined in GSMA PRD IR.88

• Diameter solution can be installed at VPMN, HPMN and IPX level

S4 SGS

VPMN HPMN

Proxy Proxy

S6a

S6d

S9

IPX

h-PCRF v-PCRF

HSS

MME

SGSN

Proxy

Agent

Proxy

Agent

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• LTE Traffic Steering

• External events based routing

• Like priority routing during “Katrina events”

• Billing proxy

• MVNO/MVNE security functions

Use Case: Specialized applications like:

Non preferred

network DSR

MM MME MME

HSS

VPLM1 VPLM2

HPLM

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3rd party applications

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Conclusions

• Diameter signaling is a fundamental part of 3G,

LTE and IMS networks

• Network usage, signaling, is very different than before

• Unpredictable

• Users, handsets and applications driven

• Purpose built Diameter Routers are needed

• Best place for DRA, DEA and more

• Diameter Routers are ideal place to add more value

• Spider in value-add web

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Peter Nas

Sr Solutions Architect Sales

Mobile: +31 628 02 59 28

E-mail: p.nas@f5.com

20 For more information visit us at: www.traffixsystems.com

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Where to use a IWF/translation agent

HLR

MME HSS

SGSN

S6, Diameter

MAP, SS7

HPLMN VPLMN

Network

Element

with Diameter

& MAP

Network

Element

with Diameter

& MAP

EIR…

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