virtualizationtechniques: opportunitiesfor fixed/mobile ... · virtualizationtechniques:...

Virtualization techniques:

Opportunities for fixed/mobile

convergence

Fabrice GuilleminOrange Labs, IMT/IMT/OLN/CNC/NCA

Networking 2015 - May 21, 2015

interne Orange2

Overview

1

2

3

4

Introduction

Convergent gateway: design principles and implementation

Further issues related to convergent gateways

Use cases

Networking 2015. Fixed/mobile/convergence and virtualization3

Introduction: Fixed/mobile convergence

� Fixed/mobile convergence is a recurrent issue in the design of networks

� Architecture of mobile and fixed access networks has been inherited from principles of the 80’s for fixed and 90’s for cellular networks

� Mobile networks are greatly centralized: all traffic converges to a few concentration points (Packet GateWays, PGW)

� architecture of cellular networks designed by 3GPP and that of ADSL/FTTH fixed networks by Broadband Forum

� However, – customers usage is changing (data traffic explosion, content

services, streaming on cellular networks, user generated content, P2P, …)

– densification of the radio coverage (3G/4G, WiFi, small/femto/macro cells)

– IP has become the common convergence layer (even if L4/L3 functions are not in force, information is already packetized according to IP principles at the access)

Key challenge: design of backhaul and mobile core networks for Key challenge: design of backhaul and mobile core networks for Key challenge: design of backhaul and mobile core networks for Key challenge: design of backhaul and mobile core networks for 5G5G5G5G


Architecture of fixed networks

IP functions actually begin above the BNG (or BAS)

DSLAM

NE

NE

BAS

STBSTBSTBSTB

PCPCPCPC

TVTVTVTV

ToIPToIPToIPToIP

Home Home Home Home GateWayGateWayGateWayGateWay

IP/MPLS backhaul

RBCI

24/24

PF Orange

VoD

NM

NC

NM

NC

OTT services

GigaBit Ethernet, use of VLAN

for wall gardened services


Architecture of cellular networks

Only a few PGW (less than 10 for the Orange France network)

OperatorServicesInternet

CorporateServices

Evolved Packet Core

PCRF

ePDG

Gb

Iu S4

S1-MME

S1-U

S11

S2c

S2a

S2b

Gx

Rx+

SGi

HSS

S6b

S5

User planeControl plane

S3

S6a

SGSN

BSC

RNC

S10

AAA

RAN

NodeB

eNodeB

PGW

S12

Gxc

SGW

MMELTE

3G

2G

Non 3GPP

Untrusted Non-3GPP IP Access

Trusted Non-3GPP IP Access

Gr/S6d

S16

SWx


Rationale for introducing a Convergent Gateway

(CGW)

� Three main drivers:– change of usage with smartphones and tablets (studies show

that users are massively using WiFi in the domestic networks)

– densification of radio network (WiFi via fixed access or hot

spots, femto, small, macro cells)

– explosion of traffic

� Usage– massive usage by customers of the wireless technology to

connect to the Internet (mobile and WiFi)

– customers wish to access the Internet without taking care of

the access technology (WiFi, 3G/4G, wired)

– The customer is surrounded by many access networks but

can hardly switch from one network to another (different

authentication, addressing, customer’s profile, routing,

charging, …)


Limitations due separate architectures

� In terms of usage:– each access network has its own addressing system and

allocates IP addresses via PPP or DHCP– NAT, local DHCP,… at the home gateway– NAT, (DHCP), … at the PGW

– Addressing systems and policies are different

Is IPv6 sufficient to overcome this problem? Unique IPv6 Is IPv6 sufficient to overcome this problem? Unique IPv6 Is IPv6 sufficient to overcome this problem? Unique IPv6 Is IPv6 sufficient to overcome this problem? Unique IPv6 address per device? What about mobility, roaming, address per device? What about mobility, roaming, address per device? What about mobility, roaming, address per device? What about mobility, roaming, etcetcetcetc . ?. ?. ?. ?

– IP address changes when switching from one access network to another

– Applications need to adapt themselves in order to be resistant to IP address changes (issues with VPN, conversational and real time constrained applications, …)

– Many applications are resilient to IP address changing (e.g., adaptive streaming) but for real time applications (voice) this for real time applications (voice) this for real time applications (voice) this for real time applications (voice) this is is is is still still still still an open issuean open issuean open issuean open issue


Cost of separate architectures

� Customers generate more and more mobile traffic– to cope with traffic explosion, centralized PGWs have to be

continually upgraded and some links of the network have to

be upgraded to carry traffic towards these gateways

� When a user switch from one network to the other, complex

signaling procedures are run (notably radio bearer

(de)activation)– because of centralized control, huge amount of signaling

traffic can appear (up to 30% of network radio capacity) all

over the network

Bearer activation is a source of latency (QUIC …)Bearer activation is a source of latency (QUIC …)Bearer activation is a source of latency (QUIC …)Bearer activation is a source of latency (QUIC …)

� Centralized functions are vulnerable points in the

architecture (Single Point of Failure, need for resilience at

extra cost)

� Separate AAA need to be maintained

Challenge: AAA without smart Challenge: AAA without smart Challenge: AAA without smart Challenge: AAA without smart cards for unified access?cards for unified access?cards for unified access?cards for unified access?


Technological trends

� L2/L1 concentration higher in the network– larger distance between ONUs and OLT in optical access

– BBU hostelling in mobile networks

– development of new convergence points in the network

(NGPoP)

– colocation of OLT and BBU hostels in NGPoPs

� Distribution of some IP features lower in the network:

NGPoP host more network services– distributed CDN to make information available closer to the

end user

– Fog computing (distribution of data centers)

Need for a new type of network element realizing the Need for a new type of network element realizing the Need for a new type of network element realizing the Need for a new type of network element realizing the

convergence between fixed and mobile convergence between fixed and mobile convergence between fixed and mobile convergence between fixed and mobile access: The access: The access: The access: The

convergent gatewayconvergent gatewayconvergent gatewayconvergent gateway


CGW:

Design principles and

implementation


CGW principles

� Convergence of various types of access at Network’s Edge:

fixed, WiFi, cellular

� Authentication for cellular and fixed access

Open issue: Need for a convergent AAAOpen issue: Need for a convergent AAAOpen issue: Need for a convergent AAAOpen issue: Need for a convergent AAA

� IP functions start at the CGW: routing, quality of service,

mobility

� Information (in form of IP packet) is delivered to the IP

collect network above the CGW– no need for centralized platforms

� Dynamic instantiation on COTS servers/switches through

Networks Functions Virtualization: flexible deployment,

configuration, upgrades, scaling

� SDN used for flexible traffic control at Network’s Edge


Location of the CGW

WiFi Hotspot (public or private)

Convergent

GW

Home Gateway

eNodeB

IP collect

NetworkInternet

Backhaul

Network

IP traffic, no GI functions (e.g., DPI)services in OTT mode

same address pool for the

APs connected to the CGW

need for a connection between

addresses and APpure IP, IP/MPLS, L2 or L1

possible colocation with NGPoPs


The functional blocks of the CGW

DHCP Server

AAA

MME (LISP PxTR)

L-ANDSF1

Monitoring

vEPC

WiFi controller

switch/router (OVS)forwarding

plane

control

plane

all the functions are hosted by virtual machines (NFV)

address allocation

authentication

mobility management

choice of the best AP

supervision of the AP

termination of GTP

tunnels

Control of the WiFi AP

CGWCGWCGWCGW

1ANDSF (Access Network Detection and

Selection function): standardized by

3GPP (centralized version), assists the

terminal to select the best AN depending

upon user’s subscription (WiFi

offloading)

all the functions

are coupled


Implementation issues

� Mobility management (MME):– intra CGW MME

– the need for MME depends on the addressing scheme used for

allocating addresses to terminals connected to APs

– either the addresses depends on APs and in that case

addresses may change when one terminal is moving from one

AP to the other � possible need for MME (LISP tested in lab,

SDN solutions under study)

– or addresses are common to all AP; in that case, need for

maintaining a map between the address and the AP for

forwarding information (convergence functionconvergence functionconvergence functionconvergence function)

– inter CGW MME– when one terminal moves from one CGW coverage to another

CGW coverage

– possible use of LISP principles if the terminal communicate the

identifier of the CGW; if a NAT is implemented in CGW (EID =

IPv6 address of the terminal, and local ID = IP address of the

CGW to maintain in the map resolver)

alternative: do nothing in alternative: do nothing in alternative: do nothing in alternative: do nothing in

the network and let the network and let the network and let the network and let

terminals manage mobilityterminals manage mobilityterminals manage mobilityterminals manage mobility


Implementation issues (cont’d)

� vEPC:– need for open source vEPC stacks

– challenge with the current vEPC: – break the link between GTP-U and GTP-C

– GPT-U should be handled by the forwarding function only

– GTP-C should be hosted by separate VMs

– address allocation should be done by the global DCHP server

– More challenging: no more GTP tunnels – use the same principles as for fixed networks without PPP

tunnels

– use of DHCP for address allocation, flat IP in the backhaul,

unified AAA unified AAA unified AAA unified AAA between fixed and wireless networks

� Monitoring– Is it possible to do monitoring in Virtual Machines? Can (soft)

switches do port mirroring at high speeds (> 1Gbit/s)?

– What is the trade-off between processing capacities and the

level of traffic analysis?


Further issues

� Charging and accounting:– The distribution of the mobile core makes it

difficult to count traffic/user

– reinvent charging? End of capped offers?

� CGW instantiated in (mini) data centers– possibility to couple with added value

services:

– WebRTC TURN servers to enable

WebRTC services

– CDN servers co-located with the CGW

– ….

� Quality of service and traffic management– monitoring functions and Local-ANDSF to

perform traffic and QoS management

– possible API for QoS negotiation

– how to manage QoS without radio

information? Couple traffic management with

BBU hostels?

AAAAAAAAAAAAAuthentAuthentAuthentAuthent

Accounting

MobilityMobilityMobilityMobility(MME, EPC)(MME, EPC)(MME, EPC)(MME, EPC)

Convergence Convergence Convergence Convergence

Fixe/Fixe/Fixe/Fixe/dMobiledMobiledMobiledMobile

MonitoringMonitoringMonitoringMonitoring(ANDSF, …)(ANDSF, …)(ANDSF, …)(ANDSF, …)

DHCPDHCPDHCPDHCP(Ipv6, …)(Ipv6, …)(Ipv6, …)(Ipv6, …)

NFVNFVNFVNFV

SDNSDNSDNSDN

SecuritySecuritySecuritySecurity

MNGTMNGTMNGTMNGT

OAMOAMOAMOAM

CloudCloudCloudCloud

OVS, ODL, vEPC, …

AddedAddedAddedAdded

Value Value Value Value

ServicesServicesServicesServices

HAHAHAHA

ScalabilityScalabilityScalabilityScalability


Use cases for fog/edge

computing


Introduction to use cases

� The CGW can be coupled to Service/Content processing

and storage facilities at the Network’s Edge

� Possible services which could associated with a CGW– Services, (WebRTC)

– Content (incl. User Generated), mini CDN nodes

– business cloud,

– IoT data,

– user’s assistance,

– …

� Several use cases can be anticipated…


Business premises

CGWCGW1

2Operator’s core(possibly incl. AAA/HSS)

The CGW is a gateway of the LAN of a business customer,

which can optimize the use of radio resources (especially for data)

For cellular sessions, the operator’s mobile core can be used for AAA


For backhauling crowds

Operators HSS

Event

CGW

Operators

Networks

In the case of crowded events, the cellular network is often saturated

The CGW can be used to backhaul radio APs (cellular with limited range or WiFi)


Further issues related to

a CGW


CGW “on the fly”

� The basic design principles of a CGW is that this element

should be instantiated on the fly on data centers

(OpenStack) distributed at network edges (fog computing)– there is hence a need for a tool capable of configuring such

elements (typically OpenStack)

– But CGWs should be interconnected, sometimes with

bandwidth constraints

– OpenStack is not sufficient by itself, there is a need for a tool

able to configure the network in order to interconnect CGW

(e.g., OpenDaylight), typically when used to backhaul an

enterprise network

� OpenDayLight and Openstack have been developed for

given purposes, there is a need for a tool with a global view

of the network in terms of storage, computing and

bandwidth

�� GlobalOSGlobalOSGlobalOSGlobalOS


OpenDayLight (open source, hosted by the Linux

foundation)


OpenStack (for cloud – mainly, compute and

storage)


Configuration of a CGW (OpenStack – centralized

view)

L3/L2 tunnel L3/L2 tunnel L3/L2 tunnel L3/L2 tunnel tunneltunneltunneltunnel

OpenStackOpenStackOpenStackOpenStack

NovaNovaNovaNova

NeutronNeutronNeutronNeutron[ceilometer][ceilometer][ceilometer][ceilometer]

network network network network

configuration of configuration of configuration of configuration of CGWCGWCGWCGW

Network tunnel Network tunnel Network tunnel Network tunnel configuration.configuration.configuration.configuration.

VM (AAA)VM (AAA)VM (AAA)VM (AAA)

Switch/router Switch/router Switch/router Switch/router (e.g. OVS)(e.g. OVS)(e.g. OVS)(e.g. OVS)

Neutron Neutron Neutron Neutron agentagentagentagent

VM (VM (VM (VM (vEPCvEPCvEPCvEPC))))

CGWCGWCGWCGW





CGWCGWCGWCGW

Openstack can control and configure a CGW from the edge (nothing in the network)



Data center Data center


Configuration of a CGW (OpenStack + ODL)







NovaNovaNovaNova


VM VM VM VM (AAA)(AAA)(AAA)(AAA)




CGWCGWCGWCGW


VM VM VM VM (AAA)(AAA)(AAA)(AAA)



CGWCGWCGWCGW



OpenDaylightOpenDaylightOpenDaylightOpenDaylight

Neutron serviceNeutron serviceNeutron serviceNeutron service


NovaNovaNovaNova


NodeNodeNodeNodeconfigconfigconfigconfig....

NodeNodeNodeNodeconfigconfigconfigconfig....


Configuration of CGW (orchestration)

configuration of CGWconfiguration of CGWconfiguration of CGWconfiguration of CGW



configuration of CGWconfiguration of CGWconfiguration of CGWconfiguration of CGW



NovaNovaNovaNova






CGWCGWCGWCGW





CGWCGWCGWCGW



OpenDaylightOpenDaylightOpenDaylightOpenDaylight

Neutron serviceNeutron serviceNeutron serviceNeutron service


NovaNovaNovaNova


Node Node Node Node configconfigconfigconfig./monitoring./monitoring./monitoring./monitoringNode Node Node Node configconfigconfigconfig./monitoring./monitoring./monitoring./monitoring

orchestratororchestratororchestratororchestrator

(network (network (network (network

abstraction)abstraction)abstraction)abstraction)request for VM configurationrequest for VM configurationrequest for VM configurationrequest for VM configuration

resource reportingresource reportingresource reportingresource reporting

request for VM configurationrequest for VM configurationrequest for VM configurationrequest for VM configuration

resource reportingresource reportingresource reportingresource reporting

network configuration requests/network configuration requests/network configuration requests/network configuration requests/

network abstractionnetwork abstractionnetwork abstractionnetwork abstraction


Global OS: first view

Openstack OpenDayLight

orchestration by using network abstraction

(topology, resources, etc.), scheduling, etc.


data

centerdata

center

data

center

configuration and monitoring

(openflow, netconf, etc.)

Services Security …

API

Global OS

(network programming(network programming(network programming(network programming

language)language)language)language)


GlobalOS framework

Network orchestrator

Network data base

Network data collector Network drivers

Resource allocation Network characteristics

Fault mgt

Perf. mgt


Network programming language

� Very active domain of research

� Many languages have been proposed so far– static approach

– NetKAT (Kleen Algebra with Test): express network procedures

into an equational system (for formally proving properties of

procedures)

– NICE

– MERLIN

– dynamic approach– Kinetic

– VeryFlow

� Most languages are packet based and do not include

resource allocation aspects


Conclusion

� Virtualization techniques offer new possibilities for

networking– instantiation of VMs on the fly for specific tasks (in particular NFV)

– Convergent gateways: package of VMs realizing control for

fixed/mobile convergence (vEPC, AAA, DHCP, convergence

functions, etc.)

� Convergent gateways raise many issues– addressing, AAA, and mobility management

– new charging scheme (more difficult to count traffic per user, capped

offers vs. usage/network conditions)

– monitoring: Is it possible to instantiate network probes on VM instead

of dedicated hardware?

� Convergent gateways can be included in a more general

framework: GlobalOS– a global OS acts as the OS of a computer but at a network scale

– need for abstraction of network resources

– resource management, language for network configuration, etc.


Thank you

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