Stateless user-plane architecture for virtualized EPC (vEPC)

Stateless user-plane architecture
for virtualized EPC (vEPC)
http://tools.ietf.org/html/draft-matsushima-stateless-uplane-vepc-01
Ryuji Wakikawa
Satoru Matsushima
Today
EPC Core
HSS
RAN
MME
SGW
PDN-GW
PCRF
AAA
Internet
2
Network Function Virtualization
Virtualized EPC on Hypervisor
HSS
vEPC
RAN
Core
Backbone NW
MME
SGW
PDN-GW
PCRF
AAA
Internet
WHY: All packets incl. control signaling are routed to vEPC.
3
Splitting Control and User Plane
vEPC
Control-Plane
RAN
Core
Backbone NW
Internet
User-plane
Goal: User packets bypass vEPC
4
Motivation
vEPC creates and
manages UE’s state.
RAN
vEPC
Core
Backbone NW
l  Router?
l  LMA/MAG?
l  vSwitch?
Internet
A mechanism is required to reflect states in Control plane to routers in User plane.
• 
• 
• 
• 
Routing protocols (BGP in our draft)
Extension to Proxy Mobile IP (draft-wakikawa-netext-pmip-cp-up-separation-00.txt)
SDN/OpenFlow!?
FORCES Working Group
5
Stateless user-plane architecture Overview
l 
Note: any questions regarding 3GPP specific question or
backward compatibility are answered in offline.
l 
What we support in the draft
l  Motivation, Benefits of NFV, Requirements
l  BGP update between Control and User planes
l  Handover mechanism
l  Address delegation mechanism
l  IPv4 support mechanism
l  Backward compatibility: Control plane is untouched.
l  When
special handling is needed like roaming, packets are routed
to vEPC.
Configuration
vEPC
EPC-E
(router)
RAN
GTP
Router
IPv6
Core NW
Internet
anycast address
(RAN side)
GTP is established to
anycast address of EPC-E
8
Route Update
vEPC
BGP Update
Dst: 2001:abcd:efgh::/64
NxtHop: GTP tunnel + TEID (demultiplexer)
RAN
GTP
Internet
Operator’s
aggregated prefix
BGP Update
Dst: 2001:abcd::/32
NxtHop: one of EPC-E
2001:abcd:efgh::/64
BGP Update Remote Next Hop
draft-vandevelde-idr-remote-next-hop
BGP Update(Normal)
9
Route Update
vEPC
Routes at all the EPC-E
2001:abcd:
efgh::/64
Destination
NextHop
Routes at routers
Destination
2001:abcd::/
32
NextHop
One of EPC-E
GTP tunnel
RAN
GTP
2001:abcd:efgh::/64
Internet
Operator’s
aggregated prefix
Host Routes are aggregated
10
Handover
Hand-over
Signaling
RAN
vEPC
New Routes at EPC-E
Destination
UE Prefix
NextHop
GTP tunnel @
New eNB
Internet
GTP
hand-over
BGP Update Remote Next Hop
draft-vandevelde-idr-remote-next-hop
11
Address Delegation
② Reverse Lookup
Destination
NextHop
…
…
2001:db8::/64
GTP Tunnel
vEPC
①　RS or DHCPv6 Req
Internet
③　RA or DHCPv6 Res
(Delegate 2001:db8::/64)
12
Backward compatibility S8
Roaming
Partner
SGW
S4
SGi
S5
PGW
Service
network
(IMS, etc)
Hypervisor
vEPC
Existing
Core
GTP
RAN
EPC-E
(router)
Router
IPv6 Core
Backbone NW
Internet
Operator’s
aggregated prefix
anycast address
(RAN side)
GTP is established to legacy
EPC located in vEPC cloud.
13
Study Items: BGP capability
An existing BGP Route Reflector can
send over 5M/sec BGP updates!*
*: We still need to investigate statistics of number of handover event in deployed cellular network
Source: ISOCORE Technical Report!
http://www.cisco.com/en/US/prod/collateral/routers/ps9343/ITD13029-ASR1000-RP2Validationv1_1.pdf
IPv4 Support
IPv4 address
allocation
(GTP control-plane)
vEPC
DS-Lite B4
or
464XLAT CLAT
(Stateless)
GTP
(IPv4-Only)
DS-Lite AFTR
or
464XLAT PLAT
(Stateful)
Internet
IPv4 over IPv6
or
v4v6 translation
15

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