Virtualization of VoIP Application Servers for Implementation of Private Unified Communication Services via LTE

18. VDE/ITG Fachtagung Mobilkommunikation 15. - 16. May 2013 - Osnabrück, Germany

Virtualization of VoIP Application Servers for Implementation of

Private Unified Communication Services via LTE

Claas Felix Beyersdorf, Diederich Wermser, Daniel Hartmann (Ostfalia University of Applied Sciences, Re-search Group IP-based Communication Systems, Salzdahlumer Str. 46/48, D-38302 Wolfenbüttel).

Xing Cao (IANT Applied NGN Technologies GmbH). Contact: [email protected]

Abstract

Today’s LTE networks with their Evolved Packet Core architecture (EPC) provide an excellent platform for transparent integration of mobile User Agents (UA) into corporate VoIP and Unified Communication (UC) envi-ronments. Voice over LTE (VoLTE) can either be controlled by IP-Multimedia Subsystem (IMS) run by mobile network operators or by external Application Servers (AS) run by other parties.

This paper introduces first approaches and research goals of an R&D project focussing on solutions for imple-mentation of corporate VoIP and UC services by external Application Servers. Virtualization of Application Servers for real-time communication services is a particular focus of the considerations.

1

Introduction

Large organisations like companies intend to have private communication networks or services, which seamlessly include all employees, wherever they geo-graphically are and whatever communication device they just use. Beyond store-and-forward services like e-mail this is also expected for Real-Time-Communication (RTC) like voice or video services. As long as only circuit switched mobile networks like GSM could meet the requirements of RTC, Closed User Group services were offered by respective mobi-le network operators. However, these services only of-fer a set of standard features limited by supplementary services or IN-features run by the operator.

LTE with EPC as core-network for the first time ena-bles RTC over IP in mobile WANs and thus the possi-bility to have full feature-transparency for corporate UC Services to roaming mobile devices.

2

Seamless Integration of

Mo-bile Users to Company RTC

2.1

Traditional FMC becomes obsolete

The traditional solution to achieve integration of mo-bile users into company RTC services when using cir-cuit switched mobile networks like GSM are known as Fixed Mobile Convergence (FMC) [2]. For a caller the current whereabouts of an FMC client and its mo-bile number of the appropriate public momo-bile network is not visible.

Figure 2 illustrates the handling of a mobile originat-ed call (MO) in FMC, when only circuit switchoriginat-ed connectivity is provided by the mobile network. Fig-ure 3 shows the handling of an MO call applicable, when the mobile network offers non-RTC capable IP-connectivity like GPRS in parallel to circuit switched RTC. In both scenarios the FMC controller inside the corporate network establishes the required connec-tions.

Figure 1 Scenario FMC use his public nario 2 ad with IT-a provided, the comp Figure 2: Figure 3 RTC-cap 1: LTE / EPC

1 does not all er is limited to c mobile netw dvanced prese applications of , as the entire panies RTC ser : Pure CS ba 3: FMC Solu pable IP Conn C with IMS an

low for feature o the CS feat work operator. ence services f the respectiv e signalling fo rver is done o sed FMC Sol ution with C nectivity in M nd Private Ap e transparency ture set offere

In contrast in or CTI-integr ve company ca or call control ver IP. lution CS RTC and Mobile Netwo pplication Se y, the ed by n sce-ration an be with non ork

2.2

Figu netw Diff EPC base [19] Qua leve (eM Cha the n ing Serv Tabl 23.2 3GP Tab erver Control

RTC se

ure 1 gives a work elements ferent from pr C/LTE works ed on IP. VoIP . ality of Service el Precedenc MLPP) can be rging Rules F network oper the Diamete vers. le 1 lists the 203 [7], the e PP TS 22.067 le 1: QoS Cla

lling QoS Par

ervices base

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ed on EPC

view on LTE/ ularly relevant e network tec also RTC ser requently call meters as well -emption Me hrough the P RF) either by a gh the Rx Int y external A as defined in hanisms are d s [7] mplified)

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2.3

P

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Private AS

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f mobile RTC ompany’s RTC

for RTC S

s, replacing ore and more d providers. to run RTC rver infrastruc s with respec architecture a io: ipXecs [3]as a egration of m s can either i nes offered by ing an approp ) or use the work through ol QoS param e transparency ter alternative hand requirem C services now C servers.

Services

traditional on e offered as c services for m cture and are f

ct to availab alternatives to an SSOA Exa mobile inter-y the priate LTE h SGi meters y for e has ments w are n-site cloud many faced bility. o im-As clos tena How tuali softw lized for c integ Maj cont com load like tion or E ample, modif  One Mul tenancy share the  Virtualiz applicati far as known ed user group ancy.

wever, for priv isation has a ware not deve d and moreov customer indi grated.

or requiremen text are scalab mponents in or d balancing. M

SIP, XMPP an with commo ERP are needed

fied from [1]

lti-tenant impl environment e same applica zation with (op

on software fo n by the auth ps for corpora vate AS to pro number of a eloped for mu ver additional vidual service nts for RTC s bility as well rder to achiev Moreover op nd REST to al on enterprise d. lementation. I t, multiple ation software ptionally) an for each custom thors, IMS im ate customers ovide RTC Ser advantages. A ulti-tenancy c l software co e features can server solutio as redundanc ve high availa pen standard allow function applications l In a multi-customers e. individual mer. mplements by multi-rvices vir-Application can be uti-omponents n easily be ons in this cy of main ability and interfaces al integra-like CRM

3

A

S

Running vironmen ing the s applicatio (UC) in which wi When it c ticular no cesses. T uncritical handling Assuming server ar the virtua provide t high prior Figure 5:

Aspects o

Servers

services like w nts is nothing spectrum of v ons like VoI

general req ill be discusse comes to virtu otice has to b The signalling l, since SIP h [13]. g that CPU an re properly di al machines (V the appropriat rity VMs at an : I/O is Critic

of Virtuali

web or e-mail special nowa virtualized ser IP or unified quires a care d in this chapt ualizing of Vo be taken of m on the other has its own t

nd RAM resou imensioned, t VM) can be ea te CPU and R ny time. cal for RTC S

ized RTC

l in virtualized adays. But exp

rvices to real-d communica eful investiga ter. oIP systems, a media-related hand is relat timing- and e urces of a phy the hyperviso asily configur RAM resource Services

C

d en- pand--time ations ation, a par- pro-tively error-ysical or for red to es for I/O dia r trans direc isoc (NIC out a a vi suffe sam with by a NIC Asid audi Mus call driv HDD tem, Pres load With publ men struc resp the To m nent sam vest or li man whic Othe activities are related VoIP p sfer 50 packe ction. At best hronous inter C) has to be e

any jitter. Sinc irtualized mac fer from high j

e NIC simult h pass-through allowing a hig C exclusively. de the presenc io data for In sic on Hold ( detail records es (HDD) of Ds having the , it has to be sence Service, d scenario caus h further notic lic operator’s nted by the pr cture of an S pective and op physical hard meet the dema ts (i.e. databas e physical har igated, if the imits the inte nce, in particu ch cause addit er planned exa  An SSO services ical host  More th same phy  Distribut across a more problem process of an ets per second t, those packe

val; the netwo exactly trigger ce the NIC act chine, an outg itter, if other V aneously. Usi h mechanisms gh priority VM ce information nteractive Voi (MoH), the a s (CDR) get s f the physical slowest acces e examined, i IVR or MoH sed by lots of ce on high ava architecture ivate SSOA’s SOA allows e ptionally redu dware of a vi anded HA, no ses) must be d rdware. Furth potentially hi ended scalabil ular the sync tional network aminations: OA in paralle like CRM or . an one SSOA ysical host. tion of seve wide range of matic (Figure SSOA norma d of RTP data ets should be work interface red at each 2 ts as a virtual tgoing RTP st VMs heavily ing several N s can ease thi M to access on n, the call-stat ice Response actual registra stored on the l server, as w ss times in a w if UC service H get affected i f VMs with dis ailability, the now has to s operator. Th easy distribut undant proces irtualized env o redundant U distributed ont hermore, it has igher granular lity and overa chronization k traffic. el to other n web on the sa A “competing eral virtualize f physical hos 5). A me-ally has to a for each sent in an controller 0ms with-switch on tream can access the NICs along s problem ne specific

tes and the (IVR) or ations and hard disc well. With whole sys-es like the in a heavy sc access. HA of the be imple-e modular ion of the ses across vironment. UC compo-to the very s to be in-rity serves all perfor-processes, on-critical ame phys-g” on the ed SSOA ts.

4

C

R

Many co which is BYOD (B day’s em text of de eration. F for mobil not to ma However fers an ex services o Applicati parent IP IMS vend support W vices [20 Figure 6 and medi SSOA (F Agent arc Figure 6: Figure 7:

Clients fo

RTC Serv

ompanies aim one way to Bring Your Ow mployees. Usab esktop-virtuali For smart pho le RTC servic ake sense. r, WebRTC [1 xcellent portab on smart phon ion Servers b -transport in L dors like Erics WebRTC clien ]. and Figure 7 ia for a simp Figure 6) resp chitecture for : WebRTC pr : WebRTC pr

or Private

vices

m for deskt o cope with wn Device), a bility of softp ization needs ones as domin es, desktop vi 2] as extensio ble thin client nes to interact based on QoS

LTE/EPC mob sson have alre nts for IMS-ba 7 illustrate ro ple two-party pectively a B the RTC AS ( rotocol stack rotocol stack

e Mobile

top virtualiza the challenge as asked for b phones in the additional co nant client dev irtualization s on for HTML t solution for t with private S-controlled t bile networks. eady announc ased real-time outes of signa call, when u ack-to-Back-U (Figure 7). with SSOA with B2BUA ation, es of by to- con- onsid-vices eems L5 of-RTC RTC trans-. ced to e ser-alling using User-A

5

This enab mob Furt of R men ters in th As l erag It en troll voic tenti yond exte used ter 2 Also smar catio

Outlo

s paper consid ble seamless a bile users, base

ther research a RTC Applicati ntation of tests for media ser he virtualizatio

long as LTE r ge, Voice Call nables seamle led by an IM ce transmission ial solutions o d the LTE co ernal corporat d. Traditional 2.1 could perh o, usability of rt phones in i on servers nee

ok

ders a variety access to corp ed on LTE/EP activities will ion Servers an s, that proof k rvices under e on environmen adio networks Continuity (V ess handovers S) and GSM-n outside the L offering an eq overage need te RTC appli FMC solution aps contribute WebRTC for interaction wi eds more thoro

y of aspects r porate RTC se PC mobile netw l focus on virt and in particu keeping of Qo extreme load nt. s have insuffi VCC) has to b s between VoL -based circuit LTE coverage quivalent exte to be addres ication server ns as describe e to this aspec mobile RTC ith external R ough consider relevant to ervices for works. tualization ular imple-S parame-situations icient cov-be applied. LTE (con-t swi(con-tched e [11]. Po-ension be-ssed when rs will be d in chap-ct. Clients on RTC appli-ration.

6

References

[1] Schumacher, Jan; Wermser, Diederich: VoIP-TK-Anlagen auf Basis von Open Source. Berlin-Offenbach: VDE-Verlag, ntz 7-8, Nov. 2009. [2] Shneyderman, Alex; Casati, Alessio: Fixed

Mo-bile Convergence. McGraw-Hill, 2008.

[3] Picher, Michael W.: Building Enterprise Ready Telephony Systems with sipXecs 4.0. Packt Pub-lishing, 2009.

[4] SIPfoundry open source community. http://www.sipfoundry.org, April 2013.

[5] Hartmann, Daniel; Stephan, Mark; Cao, Xing et al.: Initial Development of a SIP-/RTP-based Core Network for the TETRA Mobile Radio System aiming at Transparent Availability of its Features in LTE. Osnabrück: 16. ITG-Fachtagung Mobilkommunikation, 2011.

[6] Pankratz, René; Hartmann, Daniel; Wermser, Diederich: Spezielle Anforderungen an Virtuali-sierungslösungen für Software-basierte VoIP-PBX. Leipzip, HfTL Science Days, 2010. [7] 3GPP TS 23.203: Policy and charging control

architecture. Release V12.0.0, 2013-03.

[8] 3GPP TS 29.213: Policy and charging control signalling flows and Quality of Service (QoS) parameter mapping. Release V11.6.0, 2013-03. [9] 3GPP TS 22.011: Service accessibility. Release

V12.0.0, 2013-03.

[10] 3GPP TS 22.067: enhanced Multi Level Prece-dence and Pre-emption service (eMLPP). Relea-se V11.0.0, 2011-09.

[11] 3GPP TS 23.206: Voice Call Continuity (VCC) between Circuit Switched (CS) and IP Multime-dia Subsystem (IMS). Release V7.5.0, 2007-12.

[12] Web Real-Time Communication. http://www.webrtc.org/, April 2013.

[13] Trick, Ulrich; Weber, Frank: SIP, TCP/IP und Telekommunikationsnetze. 4. Auflage, Mün-chen: Oldenbourg Verlag, 2009.

[14] Poikselkä, Mikka et al.: The IMS. West Sussex: John Wiley & Sons Ltd, Reprint of 2004. [15] Dahlman, Erik et al.: 3G Evolution. 2nd Edition,

Burlington: Academic Press, 2008.

[16] Lescuyer, Pierre; Lucidarme, Thierry: Evolved packet Systems (EPS). West Sussex: John Wiley & Sons Ltd, 2008.

[17] Agbinya, Johnson: IP Communications and Ser-vices for NGN. Boca Raton: CRC Press, 2010. [18] Olsson, Magnus et al.: SAE and the Evolved

Packet Core. Burlington: Academic Press, 2009. [19] Ericsson White Paper: Voice over LTE.

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[20] Gabriel, Caroline: Ericsson pushes WebRTC be-yond the phone. http://www.rethink- wireless.com/2013/01/10/ericsson-pushes-webrtc-beyond-phone.htm , 2013.

7

Abbreviations

AS Application Server B2BUA Back-to-Back User Agent BYOD Bring Your Own Device CRM

Customer-Relationship-Management

CSCF Call Session Control Function eMLPP enhanced Multi-Level Precedence

and Pre-emption EPC Evolved Packet Core

ERP Enterprise-Resource-Planning FMC Fixed Mobile Convergence GPRS General Packet Radio Service GSM Global System for Mobile

Commu-nications

HA High Availability HSS Home Subscriber Server IMS IP Multimedia Subsystem IN Intelligent Network

IP Internet Protocol

IVR Interactive Voice Response LTE Long Term Evolution

MO Mobile Originated

MoH Music on Hold NGN Next Generation Network NIC Network Interface Controller PBX Private Branch Exchange

PCRF Policy and Charging Rules Function PDN Public Data Network

PSTN Public Switched Telephone Network QoS Quality of Service

RAN Radio Access Network REST Representational State Transfer RTC Realtime Communication RTCP Realtime Transport Control Protocol RTP Realtime Transport Protocol SAE System Architecture Evolution SBC Session Border Controller SIP Session Initiation Protocol SPR Subscriber Profile Repository SRVCC Single Radio Voice Call Continuity SSOA SIP Service Orientated Architecture

UA User Agent

UE User Equipment

UC Unified Communication

VM Virtual Machine

VPN Virtual Private Network VoIP Voice over IP

VoLTE Voice over LTE WAN Wide Area Network

XMPP Extensible Messaging and Presence Protocol