Support for Network-based User Mobility with LISP

Support forNetwork-basedUser Mobility with LISPANDREA GALVANI

SUPERVISORPROF. FULVIO RISSO

ACADEMIC TUTORSPROF. ALBERT CABELLOS-

APARICIOM.S. ALBERTO RODRIGUEZ-

NATAL

Wi-Fi Mobility

Users switching between Wi-Fi networks

(Handover)

Scenario

A user is doing a VoIP call,

or exchanging a file, ...

Scenario

The user decides to change Wi-Fi networkThe connection is dropped and has to be reinitialized

Scenario

The user decides to change Wi-Fi networkThe connection is dropped and has to be reinitialized

ProblemA TCP connection is represented by a 4-tuple:

<source IP, source Port, destination IP, destination port>

When the user moves, his IP changesThe TCP connection is released

“Network-based”Host-based: additional software needs to be installed on the user’s host

Network-based:No modifications to users’ devices required

The network components take care of the mobile hosts’ mobility

GoalsConnection continuity when roaming across Wi-Fi networks

Users’ devices use standard TCP/IP stack

Network components are in charge of managing users’ mobility

Minimize modifications to other components

Keep a high level of abstraction for future developments

State of the artIETF standards

•Mobile IP v4 / v6

•Proxy Mobile IP v6Adopted in 3G networks

...No standards for Wi-Fi networks

IP address constraint

The IP address represents two properties at the same time

• User’s identity• User’s location

User’s location changes → User’s IP changes

LISPLocator/ID Separation Protocol

Loc/ID split• One address space for user’s identity(EID – Endpoint IDentifier)

• One address space for user’s location(RLOC – Routing LOCator)

User’s location changes → User’s RLOC changes

LISP overview• xTR (Edge Router)

• Subnetwork with EID-prefix

• Users in the network are given an EID from the prefix

• A Map-Server is used for storing mappings

• A Map-Resolver for retrieving mappings

RLOC: 130.1.1.3

EID – RLOC10.1.1.0/24 – 130.1.1.3

EID-prefix:10.1.1.0 /24

EID: 10.1.1.7

Internet

LISP in a nutshellRLOC: 130.1.1.3

EID: 10.1.1.1

RLOC: 150.1.1.5

EID: 10.1.2.3

IP 10.1.1.1 → 10.1.2.3

ICMP ping Map-Requestfor 10.1.2.3Map-Reply

10.1.2.3 – 150.1.1.5

EID-prefix:10.1.1.0 /24

EID-prefix:10.1.2.0 /24

1

2

3

Internet

LISP in a nutshellRLOC: 130.1.1.3

EID: 10.1.1.1

RLOC: 150.1.1.5

EID: 10.1.2.3

IP 10.1.1.1 → 10.1.2.3

ICMP ping

IP 10.1.1.1 → 10.1.2.3

ICMP pingIP 130.1.1.3 → 150.1.1.5

UDP 4341 -> 4341

LISP (Data)

IP 10.1.1.1 → 10.1.2.3

ICMP ping

EID-prefix:10.1.1.0 /24

EID-prefix:10.1.2.0 /24

RLOC: global scope

EID: local scope

4

5

Idea

150.1.1.5

130.1.1.3

10.1.1.1

User’s mapping10.1.1.1 – 130.1.1.3

10.1.2.3

Idea

Update user’s RLOC when he moves

Establish TCP connections using EIDs

150.1.1.5

130.1.1.3

10.1.1.1

User’s mapping10.1.1.1 – 150.1.1.5

10.1.2.3

Solution Design – LISP-ROAM

A solution to be implemented by Internet Service ProvidersNew mobility serviceFull trust agreementPossibility to roam across every network

User is assigned a fixed EID

Five StepsEverytime a user connects to a network...

1. User authentication

2. User’s EID retrieval

3. User’s local configuration

4. User’s home Map-Server retrieval

5. User’s location update

1. User authentication

We need to keep track of the user while he moves

802.1x standard

xTR checks credentials with RADIUS

RADIUS Server stores users’ credentials

[email protected]***

EAP

RADIUSRADIUSServer

domainA.com

Username Password

alice ***

bob ***

Username

Password

EID

alice *** 10.1.2.121

bob *** 10.1.2.137

2. User’s EID retrieval

The RADIUS Server can store multiple attributes

It’s possible to store user’s EID

The RADIUS Server returns the EID embedded in the Access-Accept

[email protected]***

domainA.com

Access-Requestalice, ***

Access-AcceptEID = 10.1.2.121

1

23

3. User’s local configuration

• If the user is in his home networkHe’s part of the EID-prefix

10.1.1.169

EID-prefix:10.1.1.0 /24

3. User’s local configuration

• If the user is in his home networkHe’s part of the EID-prefix

• If the user is foreignA local virtual interface is created

The xTR is the default gateway for the user

10.1.2.121

10.1.2.122

EID-prefix:10.1.2.120 /30

EID-prefix:10.1.1.0 /24

User’s home Map-Server

One Map-Server per domainAll Map-Servers form a

Distributed Mapping System

Home Map-ServerHome domain’s Map-

Server

Every xTR knows the key related to its EID-prefix domainA.com

EID-prefix:10.1.1.0 /24

EID-prefix:10.3.3.0 /24

130.1.1.3

Map-Register10.3.3.0/24 – 130.1.1.3

Authenticated

130.1.1.1

Home Map-Serverof domain A

4. User’s home Map-Server

When a foreign user connects to a network

the xTR has to retrieve user’s home Map-Server’s...

1. Address Can be done using the LISP infrastructure...or through other systems (DNS)

2. Key ...use RADIUS attributes

4. User’s home Map-Server address

EID RLOC

10.1.2.0/24 80.8.8.1

130.1.1.3

EID-prefix:10.1.1.0 /24

80.8.8.1

EID-prefix:10.1.2.0 /24

domainA.com domainB.com

[email protected]***

80.8.8.5

10.1.2.121

Map-Request10.1.2.121

IP 80.8.8.5 → 130.1.1.3

UDP 4342 → 4342

LISP 10.1.2.121 – 80.8.8.1

Map-Server’s IP =outer source IP

Map-Reply

1

23

Username

Password

EID Map-Server key

alice *** 10.1.2.121 «secret»

bob *** 10.1.2.137 «secret»

4. User’s home Map-Server key

Home Map-Server’s key returned with Access-Accept

domainA.com

Access-AcceptEID = 10.1.2.121

Key = «secret»

1

2

3

5. User’s location update

EID RLOC

10.1.2.0/24 80.8.8.1

130.1.1.3

EID-prefix:10.1.1.0 /24

Map-Register10.1.2.121 – 130.1.1.3

Authenticated

80.8.8.1

EID-prefix:10.1.2.0 /24

domainA.com domainB.com

[email protected]***

EID RLOC

10.1.1.0/24 130.1.1.3

Username alice

EID 10.1.2.121

MS address

80.8.8.5

MS key «secret»

80.8.8.5

10.1.2.121/32 130.1.1.3

Update correspondent nodes

Map-Register for 10.1.2.121

Map-NotifyMap-Notify

Solicit-Map-

Request

for 10.1.2.121

Map-Request

/ Map-Replyfor 10.1.2.121

10.1.2.121 10.1.2.121

LISP Map-Server / Map-Resolver

Correspondent node

1

2

3

44

5 6 7

Test bed

EID-prefix:10.1.1.0 /24

«LISP-A»

10.1.2.121

EID-prefix:10.1.2.0 /24

«LISP-B»

[email protected]

domainA.comFOREIGN

domainB.comHOME

10.1.2.121

10.1.3.165

Handover testLatency / Packet loss

1. User home / foreign• User connects to his home / a foreign

network

2. User known / unknown• User has connected before to the

network

Results – User unknown

Results – User known

...other proposalsNo full trust between ISPsISPs don’t share Map-Servers’ key

No fixed EID for userLISP-MACLISP-RADIUS

LISP-MAC•User assigned to a specific xTR of the domainHome xTR

•MAC Mapping SystemMAChost – IPHomexTR

•When a user connects to a foreign networkDialogue between foreign and home xTR

LISP-MACEID RLOC

10.1.2.0/24 80.8.8.1

130.1.1.3

EID-prefix:10.1.1.0 /24

80.8.8.1

EID-prefix:10.1.2.0 /24

domainA.com domainB.com

EID RLOC

10.1.1.0/24 130.1.1.310.1.2.121/32 130.1.1.3

DHCP RequestMAChost

Map-RequestMAChost

Map-ReplyMAChost - 80.8.8.1

MAC EID

MAChost 10.1.2.121

DHCP Request / ACK

Map-Register /Map-Notify

Map-Register10.1.2.121 – 130.1.1.3

Authenticated

DHCP ACK10.1.2.121

MAC IPhomexTR

MAChost 80.8.8.1

1

2

34

5 6

6

LISP-RADIUS• User assigned to a specific xTR of the domain

Home xTR

• When a user connects to a foreign networkDialogue between foreign and home xTR

•802.1x dialogue User authentication IPHomexTR

LISP-RADIUSEID RLOC

10.1.2.0/24 80.8.8.1

130.1.1.3

EID-prefix:10.1.1.0 /24

80.8.8.1

EID-prefix:10.1.2.0 /24

domainA.com domainB.com

EID RLOC

10.1.1.0/24 130.1.1.310.1.2.121/32 130.1.1.3

EAP [email protected]

***

[email protected]

***Access-Accept

IPhomexTR = 80.8.8.1

MAC EID

MAChost 10.1.2.121

DHCP Request / ACK

Map-Register /Map-Notify

Map-Register10.1.2.121 – 130.1.1.3

Authenticated

DHCP RequestMAChost

Username

Password

IPhomexTR

alice *** 80.8.8.1

bob *** 80.8.8.1

DHCP ACK10.1.2.121

1

23

5

64

7

7

ConclusionsLISP-ROAM actually achieves connection continuity in user mobility

It can be considered a suitable solution for realistic scenarios (buildings, campuses, ...)

The solution has been tested in a small scope but can be considered being implemented in wider scenarios (ISP level)

The assumptions made allow future extension / interoperability with 3G operators

Video demo

Mobile host switching between Wi-Fi networks, while communicating with Correspondent Node (ping / TCP)

Thanks for your attention

Andrea Galvani

[email protected]

bit.ly/lisp-roam