Building the Mobile Internet

Building the Mobile Internet
Klaas Wierenga <klaas@cisco.com>

Consulting Engineer, Office of the CTO

April, 2012

Agenda

§  Introduction
Trends, The Mobile Internet, Mobility

§  Challenges
Sessions, Locators and Identifiers

§  Solutions
Nomadicity, Data, Network, Transport, Application, Locator-
Identifier Separation

§  Conclusions
§  Questions

Building the Mobile Internet © 20112Cisco and/or its affiliates. All rights reserved. Cisco Public 2

Content of this presentation based on:

Cisco Press, January 2011, ISBN-10: 1-58714-243-0, ISBN-13: 978-1-58714-243-7

Agenda


§  Challenges

§  Solutions

§  Questions


Media Rich Mobile Tablets and Devices—
Everyone’s Got One

50% of Fortune 500 are testing or No Wires
deploying iPads*

By 2015, tablets will constitute
50% of laptop sales**

ORGANIZATION

TIME

Source: *Apple Inc, Quarterly Financial Report, **The US PC Consumer Market in 2015 – Forrester Research

The Mobile Internet is Changing Everything

New Devices More
Broadband

New
New Pricing Applications

Video will be 66% of mobile traffic by 2014.

Scaling the Mobile Internet
Delivering 39 fold increase in Supply
39x
Growth

Macro
1000 Capacity
Average
Macro Cell
100
Growth

Efficiency

10 Spectrum

1
1990 1995 2000 2005 2010 2015

Source: Agilent


All WAN Radio Technologies Leading to
IP…
4G
3.5G
2G 3G

GSM Edge
LTE LTE-A
802.11

CDMA WCDMA
HSPA,
EVDO IP
WiMAX
WiMAX
802.16m

802.16e


The Mobile Internet

§  … is not a new Internet, but rather an evolution
(again) to deal with changed usage patterns

§  “a pervasive Internet Protocol-based network that
links fixed and mobile nodes, whether they are
sensors or servers, standalone, distributed, battery,
or line powered”

§  Mobility is a central concept


What is Mobility?

Client Mobility
•  Subscriber mobility across different radio towers
•  Subscriber mobility across radio technologies (WiFi/WiMAX/EVDO/LTE)

Device Mobility
•  Access services across multiple devices
•  Access services across multiple operator domains

Content Mobility
•  Intelligent pre-positioning of content based on subscriber trends
•  Content routing for efficient distribution of high-bandwidth content

Services Mobility

•  Network cloud model – virtualized services offered through the
network
•  Network Services available to all subscribers (wired, wireless)

Application Mobility

•  Cloud computing environment
•  Software-as-a-Service models for subscriber base


Session Persistency

§  Mobility events do not impact user traffic and allow
sessions to be maintained
§  There is persistent and there is persistent….
No perception of change by user
Application stall and resume
Application stall and no recovery

§  Some applications are more sensitive than others,
in the sense that user experience is degraded


Summary

§  Number of devices increasing
§  New types of devices
§  Use of mobile data increasing
§  No single radio network can support all demand
Capacity
Cost
Coverage
§  Roaming between radio technologies necessary
§  User Experience must not suffer
Session Persistency


Agenda


§  Challenges

§  Solutions

§  Questions


The TCP/IP 5 Layer Model

Application SMTP, HTTP, SIP, etc.
Transport TCP, UDP, SCTP, MPTCP
Network IPv4, IPv6, MIP, LISP
Link Ethernet, 3G, WiFi
Physical Fiber, Copper, Wireless

Note: No Session Layer!


What is a Session?

§  "Shared State between Communication Endpoints
that is not specific to the Network Path”

§  TCP/IP Networks don’t implement a Session Layer,
instead they use the Socket API
Abstract endpoint for a communication session called
“socket”
TCP session: {local IP, local port, remote IP, remote port,
socket id}


Socket API

Application SMTP, HTTP, SIP, etc.
Socket API {local IP, remote IP,..}
Transport TCP, UDP, SCTP, MPTCP
Network IPv4, IPv6, MIP, LISP
Link Ethernet, 3G, WiFi
Physical Fiber, Copper, Wireless


The Locator-Identifier Problem

§  IP-address functions as:
Destination for an IP-packet
Identifier of a communication session (as part of the TCP
5-tuple)
§  So when a mobile node changes its Point of
Attachment (PoA), the session breaks!

§  Solving the mobility problem is about ignoring,
solving or circumventing the Locator-Identifier
Separation problem
At different layers


Agenda


§  Solutions

§  Questions


Nomadicity

§  Use the Internet and its services regardless of
location and time
§  Roaming/Federated access to networks and
services
Not operated by the “home” operator

§  Key challenge: Authentication, Authorization and
Accounting in a roaming situation
§  Examples:
Network: 3GPP Roaming, WiFi Roaming (eduroam)
Application: SAML, IMS, DDNS based


Most Mobile Internet Usage Takes Place in Fixed
Locations ( Enterprise is a key location )
Percent of U.S. Mobile Internet Usage Taking
Place in Each Location

38% 46 minutes
On the Go 56%
§ Email
27% 33 minutes § Search
In an Office 10% § Maps
§ IM
At Home 34% 35% 43 minutes § Web Browsing
§ Entertainment

Infrequent User Everyday User

76 minutes of data activity per week per user can be
offloaded through Fixed-Mobile Convergence solutions

Source: Cisco IBSG, 2009 Base: U.S. Mobile Internet users
BRKSPM-1002_C1 © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public 20

Mobile Data Occurs at Home and Work
§  44% of data usage on smartphones occurs at
home1
§  60% of mobile data traffic will be generated in the
home by 20132 ( Infra for SP and teleworker become the same )
§  36% of mobile calls are initiated at home
One number; one address book

The mobile phone Other
19%
competes in the home Car
with the PC & TV 13%
Public Home
Transport 36%
1 Nokia smartphone survey, Dec 2007 8%
2 Informa Telecoms and Media, Work
Mobile Broadband Access at Home report, Aug 2008
24%
Source: Analysys Research 2006

Roaming/Federation

§  Authentication
Relying Party
§  Federation
Trust (roaming agreement)
§  Attribute Exchange
§  API
Identity
Transitive trust
Provider
Trust (authentication)

Client


WiFi Access with 802.1X (EAP+RADIUS)

Supplicant

Authenticator RADIUS server
(AP or switch) University A User
DB

user@university_a.nl
Internet

Employee Commercial
VLAN VLAN
Student
VLAN
signaling

data

Courtesy: SURFnet


EAP for Authentication

EAP Peer Authentication Server

EAP Method EAP Method
EAP-TLS, EAP-TTLS, EAP-TLS, EAP-TTLS,
EAP-FAST EAP-FAST
EAP-SIM, EAP-AKA, etc EAP-SIM, EAP-AKA, etc

EAP Framework EAP Framework

EAP Logical Connection

Supplicant EAP Authenticator RADIUS

Transport-Layer
Authentication RADIUS
Transport-Layer RADIUS
Method
Protocol (EAPoL)

Transfer EAP authentication
parameters


eduroam

Supplicant

Authenticator RADIUS server RADIUS server
(AP or switch) University A User University B User
DB DB

Visiting user
user@university_b.nl SURFnet

Employee Commercial
VLAN VLAN Central .nl
RADIUS
Student
Proxy server
VLAN

§  Authentication: EAP
§  Authorization: Implicit (+VLANs)

§  Attributes: RADIUS
signalling

data
§  Federation: RADIUS hierarchy

Courtesy: SURFnet

Why (not) stick to Nomadicity?

§  Allows for nomadic access
§  Many applications are (or should be) tolerant to
changing PoA
But:
§  No seamless mobility
§  Many applications are not tolerant to changing PoA
§  Requires operator involvement
Or accounts with many operators


Agenda


§  Challenges

§  Solutions

§  Questions


Data Layer Mobility

§  Below the IP-layer
§  In Data Layer domain (Ethernet)
Ethernet bridging
DHCP
WLAN mobility

§  Across Data Layer domains
Behave like a Data Layer domain
Using tunneling

§  Examples: CAPWAP, GTP, PMIPv4, PMIPv6


WiFi Mobility

Core
Tier

Distribution
Tier

Access
Tier

AP#1 AP#2 AP#3 AP#4

ü û


Control And Provisioning of Wireless
Access Points (CAPWAP)
Conventional “fat”
Wireless LAN
Access Point

IEEE 802.11
Station

“Wireless LAN
IEEE 802.11 “Light Weight Access
Station Access Point” Controller”


Inter-WLC Mobility
Controller #1 Controller
managing #2
AP#1 managing
AP#2

AP#1 on different IP AP#2 on different IP
Subnet than Subnet than
Controller#1 Controller#2

Common
Extended
BSS

Client moves from
AP#1 à AP#2


Why (not) Data Layer Mobility?

§  Solving mobility below IP-layer
§  IP PoA stable
§  Location Privacy
But:
§  Scalability Issues
Tunnels
§  Mutual trust between operators needed
§  Heterogeneous access networks
Virtual Interface Adaptors
§  Location changes invisible


Agenda


§  Challenges

§  Solutions
Nomadicity, Data, Network, Transport, Application,
Locator-Identifier Separation

§  Questions


Network Layer Mobility

§  Endpoint changes point of attachment
§  Two options:
Mobile node keeps IP-address
Hierarchical structure of IP-addressing doesn’t map to the topology, so
network can not properly route
Mobile node changes IP-address
All TCP sessions break

§  Solution: separate IP address space for routing and
for end-point identification
§  Examples: Mobile IPv4, Mobile IPv6, Dual Stack
Mobile IP, IKEv2 Mobility and Multihoming, VPN
solutions with Auto-reconnect


Mobile IPv4

§  2 IP “Layers”
Endpoint Identifiers
Routing

§  Mobile Node has a persistent IP-address in the
home network (Home Address)
§  Mobile Node informs the home network of the IP-
address of the current PoA (Care of Address)
§  Traffic is tunneled between home network and
Mobile Node
Either all traffic or just Correspondent Node originated


Mobile IPv4 routing with FA CoA
Home Agent
10.1.1.254

Mobile Node A Foreign Agent
Home Address 10.1.1.1 192.168.1.254
Visited Network A Home Network Local Network B Correspondent Node
192.168.1.0/24 10.1.0.0/16 172.16.1.1

Mobile Node to Correspondent Node

Source IP Destination IP

10.1.1.1 172.16.1.1

Foreign Agent to Mobile Node Home Agent to Foreign Agent CoA Correspondent Node to Home Agent

Source IP Destination Outer Outer Inner Source Inner Source IP Destination
IP Source IP Destination IP Destination IP
IP IP
172.16.1.1 10.1.1.1 172.16.1.1 10.1.1.1
10.1.1.254 192.168.1.25 172.16.1.1 10.1.1.1
4


Mobile IPv4 routing with CCoA
Home Agent
10.1.1.254

Mobile Node A Foreign Agent
Home Address 10.1.1.1 192.168.1.254
CCoA 192.168.1.1 Visited Network A Home Network Local Network B Correspondent Node
192.168.1.0/24 10.1.0.0/16 172.16.1.1

Mobile Node to Correspondent Node

Source IP Destination IP

10.1.1.1 172.16.1.1

Home Agent to Foreign Agent CoA Correspondent Node to Home Agent

Outer Outer Inner Inner Source IP Destination
Source IP Destination Source IP Destination IP
IP IP
172.16.1.1 10.1.1.1
10.1.1.254 192.168.1.1 172.16.1.1 10.1.1.1


Why (not) Network Layer Mobility?

§  Endpoint has stable rendezvous point
TCP sessions can be maintained
Provides for location privacy

But
§  Requires Layer 2 interactions
Proxy ARP
Gratuitous ARP

§  Granularity smaller than whole node difficult
§  Tunnels


Agenda


§  Challenges

§  Solutions

§  Questions


Transport/Session Layer Mobility

§  Main protocols: TCP and UDP
TCP mostly relevant because of connection oriented character
§  This layer is aware of changing PoA and can deal with it
§  TCP assumes stable end2end path for congestion
control
§  Required functions:
Reconfiguration of host for new network (Examples: DHCP, IP
auto-config)
Ensuring reachability for new connections (Example: Dynamic
DNS)
Updating existing connections and bindings (Examples:
SCTP, MPTCP, MSOCKS, Migrate Internet Project, SLM)


Stream Control Transmission Protocol

§  General purpose transport layer protocol that can
be used instead of TCP or UDP
§  Any application that runs over TCP also runs over
SCTP
§  Similar to TCP (Point-to-point, connection oriented,
reliable delivery, congestion control, packet loss
recovery, rate adaption)
§  But different: multipath, multihoming


SCTP Multistream

Stream Client Stream Client
Non-Sequenced Data Flow

Sequenced Data Flow

Sequenced Data Flow

SCTP SCTP
Protocol Reliable Delivery, Congestion Control Protocol
Packet Loss Recovery, Rate Adaptation
IP IP
Protocol Packet Delivery Protocol


SCTP Multihoming

Client Server

Application Layer App App App App App App Application Layer

Session Layer Session Layer

Transport Layer SCTP SCTP Association SCTP Transport Layer

Network Layer IP1 IP2 IP Network Layer

Datalink Layer INT1 INT2 INT Datalink Layer

Backup Path

Primary Path


SCTP and Mobility

§  Dynamic Address Reconfiguration
Changing Primary Address
Add or Delete Addresses

§  SCTP ADDIP
Set Primary Address
Add IP Address
Delete IP Address


Why (not) Transport Layer Mobility?

§  Inherent route optimization
No reliance on tunnels
No obscuring of changing PoA
No triangular routing
§  Inherent travel of security elements
No topologically incorrect source addresses (CoA) showing up at firewalls
etc.
§  Ability to pause transmissions during temporary disconnection
§  Ability to apply per flow optimization
§  Ability to tailor transport characteristics to application needs
But:
§  Solutions require kernel changes
§  Reliance on lower layers
“Connection Manager”


Agenda


§  Challenges

§  Solutions

§  Questions


Application Layer Mobility

§  Lower layer solutions use IP-addresses as endpoint
identifiers
§  Application mobility uses non-IP identifiers
§  User-Centric Mobility
Device Orientation => Person Orientation
Session Continuity across devices
§  Basic functionality needed:
Authentication
Registration
Rendezvous Service
§  Examples: DDNS, SIP REFER, HTTP cookies, Adaptive
Video


SIP Architecture

Location
Server

SIP SIP Redirect
Registrar Server

SIP

SIP SIP

SIP User SIP SIP User
Agent Proxy Agent
Server
RTP based Media


SIP Registration

Charlie’s SIP Registrar
Phone

SIP REGISTER Request

SIP REGISTER Response
200 (OK)


SIP Digest Authentication

SIP User SIP
Agent Registrar


401 (Unauthorized)
WWW-Authenticate
header
Authorization header

200 (OK)


SIP Rendezvous

Charlie’s
SIP User Harry’s
Agent SIP Proxy SIP User
Agent
SIP INVITE Request
(SDP Offer) SIP INVITE Request
(SDP Offer)

180 Ringing
180 Ringing 200 OK
(SDP Answer)
200 OK
(SDP Answer)

ACK
RTP Media

BYE

200 OK


SIP REFER
Charlie’s Mobile
Phone SIP Proxy Harry’s
Charlie’s PC SIP User Agent
INVITE/200OK/ACK

RTP Media

REFER/202 Accepted REFER/202 Accepted

INVITE INVITE

BYE/200 OK BYE/200 OK

200 OK 200 OK

ACK ACK

RTP Media

NOTIFY (refer success)/200 OK NOTIFY (refer success) /200 OK


Why (not) Application Layer Mobility?

§  Does not need kernel changes
§  Allows for “User-Centric Mobility”
§  Correspondent node aware of changes in IP-
address of Mobile Node
Geo-Location based services possible

But:
§  Has to be done for each and every application
§  When combined with Geo-location privacy concerns
may arise


Agenda


§  Challenges

§  Solutions

§  Questions


Locator-Identifier Separation

§  Two broad categories
Introduce an extra layer to hold the Endpoint Identifier
(encapsulated within packets with Routing Locators)
Split IPv6 Address Space into part that has topological
meaning and part that identifies host
§  Both categories can be further divided into approaches
that act at the host and those that act at the border
between site and core networks
§  Examples:
HIP (extra layer at host)
LISP-MN (extra layer at border)
ILNP (address split at host)
NPTv6 (NAT66) (address space split at border)


Network Prefix Translation IPv6

§  Address independence between local and core
network
IPv6 addresses ‘inside’ don’t have to change if the prefix
announced to the outside world changes
§  Stateless
No port mapping
Default mapping mechanism of addresses
§  IP header changes
Security mechanisms that provide header protection still
fail
§  Works particularly well for site mobility


NPTv6 Operation
Internal External
Prefix: Prefix
FD01:0203:0 2001:0DB8:0
405:/48 001:/48

Internet Core
NAT66 device

Source Address: Dest Address:
FD01:0203:0405:0001::1234 2001:0DB8:5555:0001::1234

FD01:0203:0405:0001::1234 -> 2001:0DB8:001:D550::1234 -> 2001:0DB8:001:D550::1234 ->
2001:0DB8:5555:0001::1234 2001:0DB8:5555:0001::1234 2001:0DB8:5555:0001::1234

2001:0DB8:5555:0001::1234-> 2001:0DB8:5555:0001::1234-> 2001:0DB8:5555:0001::1234->
FD01:0203:0405:0001::1234 2001:0DB8:001:D550::1234 2001:0DB8:001:D550::1234


Why (not) introducing Locator-Identifier
Separation?

§  Separation of Endpoint Identifiers and Routing
Locators
But:
§  “Flag Day” not realistic
Incremental beneficial deployment

§  May require changes in hosts and/or core networks


Agenda


§  Challenges

§  Solutions
Data, Network, Transport, Application, Locator-Identifier
Separation

§  Questions


Conclusion
One size does not fit all
§  Nomadicity:
Necessary precondition, sometimes sufficient
No session continuity

§  Data layer:
Fast, invisible to upper layers
Not scalable, no visibility of lower layers

§  Network layer:
Scales well, support multiple data links, application independent

§  Transport/Session layer:
Route and flow optimization
Requires kernel changes, requires lower layer involvement

§  Application layer:
User-centric mobility, geo-tagging
Application specific, location privacy

§  Locator-Identifier Separation:
Addresses fundamental flaw
Hard to deploy


Agenda


§  Challenges

§  Solutions
Data, Network, Transport, Application, Locator-Identifier
Separation

§  Questions


Ask klaas@cisco.com or read….

;-)

<klaas@cisco.com>

Building the Mobile Internet

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