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
Networking 2015. Fixed/mobile/convergence and virtualization4
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
Networking 2015. Fixed/mobile/convergence and virtualization5
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
Networking 2015. Fixed/mobile/convergence and virtualization6
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, …)
Networking 2015. Fixed/mobile/convergence and virtualization7
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
Networking 2015. Fixed/mobile/convergence and virtualization8
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?
Networking 2015. Fixed/mobile/convergence and virtualization9
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
Networking 2015. Fixed/mobile/convergence and virtualization10
CGW:
Design principles and
implementation
Networking 2015. Fixed/mobile/convergence and virtualization11
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
Networking 2015. Fixed/mobile/convergence and virtualization12
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
Networking 2015. Fixed/mobile/convergence and virtualization13
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
Networking 2015. Fixed/mobile/convergence and virtualization14
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
Networking 2015. Fixed/mobile/convergence and virtualization15
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?
Networking 2015. Fixed/mobile/convergence and virtualization16
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
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Use cases for fog/edge
computing
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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…
Networking 2015. Fixed/mobile/convergence and virtualization19
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
Networking 2015. Fixed/mobile/convergence and virtualization20
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)
Networking 2015. Fixed/mobile/convergence and virtualization21
Further issues related to
a CGW
Networking 2015. Fixed/mobile/convergence and virtualization22
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
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OpenDayLight (open source, hosted by the Linux
foundation)
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OpenStack (for cloud – mainly, compute and
storage)
Networking 2015. Fixed/mobile/convergence and virtualization25
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
Neutron Neutron Neutron Neutron agentagentagentagent
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)
VM (VM (VM (VM (vEPCvEPCvEPCvEPC))))
CGWCGWCGWCGW
Openstack can control and configure a CGW from the edge (nothing in the network)
configuration of configuration of configuration of configuration of CGWCGWCGWCGW
Network tunnel Network tunnel Network tunnel Network tunnel configuration.configuration.configuration.configuration.
Data center Data center
Networking 2015. Fixed/mobile/convergence and virtualization26
Configuration of a CGW (OpenStack + ODL)
configuration of configuration of configuration of configuration of CGWCGWCGWCGW
L3/L2 tunnel L3/L2 tunnel L3/L2 tunnel L3/L2 tunnel tunneltunneltunneltunnel
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.
OpenStackOpenStackOpenStackOpenStack
NovaNovaNovaNova
NeutronNeutronNeutronNeutron[ceilometer][ceilometer][ceilometer][ceilometer]
VM VM VM VM (AAA)(AAA)(AAA)(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
Neutron Neutron Neutron Neutron agentagentagentagent
VM VM VM VM (AAA)(AAA)(AAA)(AAA)
Switch/router Switch/router Switch/router Switch/router (e.g. OVS)(e.g. OVS)(e.g. OVS)(e.g. OVS)
VM (VM (VM (VM (vEPCvEPCvEPCvEPC))))
CGWCGWCGWCGW
Network tunnel Network tunnel Network tunnel Network tunnel configuration.configuration.configuration.configuration.
Data center Data center
OpenDaylightOpenDaylightOpenDaylightOpenDaylight
Neutron serviceNeutron serviceNeutron serviceNeutron service
OpenStackOpenStackOpenStackOpenStack
NovaNovaNovaNova
NeutronNeutronNeutronNeutron[ceilometer][ceilometer][ceilometer][ceilometer]
NodeNodeNodeNodeconfigconfigconfigconfig....
NodeNodeNodeNodeconfigconfigconfigconfig....
Networking 2015. Fixed/mobile/convergence and virtualization27
Configuration of CGW (orchestration)
configuration of CGWconfiguration of CGWconfiguration of CGWconfiguration of CGW
L3/L2 tunnel L3/L2 tunnel L3/L2 tunnel L3/L2 tunnel tunneltunneltunneltunnel
network network network network
configuration of CGWconfiguration of CGWconfiguration of CGWconfiguration of CGW
Network tunnel Network tunnel Network tunnel Network tunnel configuration.configuration.configuration.configuration.
OpenStackOpenStackOpenStackOpenStack
NovaNovaNovaNova
NeutronNeutronNeutronNeutron[ceilometer][ceilometer][ceilometer][ceilometer]
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
Neutron Neutron Neutron Neutron agentagentagentagent
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)
VM (VM (VM (VM (vEPCvEPCvEPCvEPC))))
CGWCGWCGWCGW
Network tunnel Network tunnel Network tunnel Network tunnel configuration.configuration.configuration.configuration.
Data center Data center
OpenDaylightOpenDaylightOpenDaylightOpenDaylight
Neutron serviceNeutron serviceNeutron serviceNeutron service
OpenStackOpenStackOpenStackOpenStack
NovaNovaNovaNova
NeutronNeutronNeutronNeutron[ceilometer][ceilometer][ceilometer][ceilometer]
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
Networking 2015. Fixed/mobile/convergence and virtualization28
Global OS: first view
Openstack OpenDayLight
orchestration by using network abstraction
(topology, resources, etc.), scheduling, etc.
network network network network
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)
Networking 2015. Fixed/mobile/convergence and virtualization29
GlobalOS framework
Network orchestrator
Network data base
Network data collector Network drivers
Resource allocation Network characteristics
Fault mgt
Perf. mgt
Networking 2015. Fixed/mobile/convergence and virtualization30
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
Networking 2015. Fixed/mobile/convergence and virtualization31
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.
Networking 2015. Fixed/mobile/convergence and virtualization32
Thank you