Routing in Large-Scale Self-organized Networks

1

Routing in Large-Scale Routing in Large-Scale Self-organized NetworksSelf-organized Networks

Serge FdidaLIP6-CNRS / Université Paris 6

http://www.lip6.fr/rp/~sf

NeXtworking’03 June 23-25,2003, Chania, Crete, GreeceThe First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN NETWORKING

Fdida


2 Fdida

Future Networking IssuesFuture Networking Issues

Routing is hard! BGP Multicast Mobile Ad-Hoc P2P


3 Fdida

New routing paradigmsNew routing paradigms

Very Large Scale– Human Users & Machines– Ambiant networking, BGP scaling, – Complexity in the routing table states

Mobile– Same reasons plus PDAs, Phones, embedded

devices– Convolution of transfert functions

Overlays– Simpler to deploy, Content access– Dedicated


4 Fdida

Routing formalization?Routing formalization?

? We need to re-assess the relationship between – Address– Location (physical)– Route computation– State complexity

? Decouple– Physical network topology– « Logical » network topology


5 Fdida

Routing semantics and operationRouting semantics and operation

f(@)=L

LOCATION LLIP6

Receiver’s @Paris

132.227.74.253

ROUTINGTransfert Function f

IP Network

Sender’s @Chania

195.167.42.37


6 Fdida

ROUTING = Transfer FunctionROUTING = Transfer Function

What if Dynamicity in Time, Space?


7 Fdida

Mobile, Multicast, QoS, Content Access, Mobile, Multicast, QoS, Content Access, ……


8 Fdida

Examples: Examples: Node X, Network adress @_X, Location LNode X, Network adress @_X, Location L

IP routing– AS_x = f(IP@_X), f={RIP, OSPF, IS-IS}– If X Moves! f does not return « L »

Mobile IP– Location L = f(g(IP@_X), g=HA, f=FA– Two transfert functions are required

(convolution)Geographic routing

– Location L = f(GPS_X), GPS_X =(Lat,Long)– GPS required, but Stateless


9 Fdida

Exemples:Exemples:Node X, Network adress @_X, Location LNode X, Network adress @_X, Location L

Route Server– @_X = get(Serv), @Serv is known– L = f(@_X ), Two-phase– MPOA/NHRP

Content access– Data = f(key), f=Distributed Hash Table– f : See Chord, Pastry, Can, …


10 Fdida

Underlay / Overlay TopologyUnderlay / Overlay Topology

A E

F

C D

X

A

C

DB

E

F


11 Fdida

Overlay TopologiesOverlay Topologies

CHORDCAN

TAPESTRY


12 Fdida

Problem formalizationProblem formalization

Does it exist :– An addressing structure– An associated mathematical space

that ease routing content to mobile nodes

in a self-organized network


13 Fdida

Main problemMain problemss

Addressing structure– How many addresses per node– Of what type, use?

Impact on the topological spaceRouting in a mathematical spaceMapping a multi-dimensional data to

a one-dimensional valueRobust to mobility


14 Fdida

Region continuityRegion continuity

How can you enforce region continuity when a node leaves/moves?

Need a multi-dimension spaceShould be robust to mobilityShould scale : balance

responsabilities


15 Fdida

RequirementsRequirements

Consecutively ordered points should be adjacent in space

Can represent a space of multi-dimensions in one dimension

The space should be partitioned in a recursive way, – A node leaving the network don’t cause a

inconsistency of the routing procedure

Many paths can be used


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The Underlay DimensionThe Underlay Dimension

15

0

2

3

1

63

Adressing space Adressing space

Topology

17

Illustration with an example:Illustration with an example:Indirect routing using distributed Indirect routing using distributed location informationlocation information

Aline Viana1,2, Marcelo Amorim1, Serge Fdida1, and José Rezende2

LIP6 LaboratoryLIP6 LaboratoryUniversity of Paris VIUniversity of Paris VI

www.lip6.frwww.lip6.fr

GTA/COPPEGTA/COPPEFed. Univ. Rio de JaneiroFed. Univ. Rio de Janeiro

www.gta.ufrj.brwww.gta.ufrj.br


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Indirect routingIndirect routing

network

B

A

H

1

2

3

Separation between node identifier and node address

ANCHOR Node

ReceiverSender


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Node’s rolesNode’s roles

Identification– Universal identifier U

• Uniquely identifies a node in the real system

– Virtual identifier V• Uniquely identifies a node in the virtual topology

– Relative (topology-dependent) address E• Mapping of U in a value belonging to the relative

addressing space• Utilization of a DHT, known by all nodes of the

topology


20 Fdida

Topology creationTopology creation

The nodes are identified by their relative addresses, which are based on their neighborhood (mobile nodes)

When a node joins the network, it receives a control region from one of its neighbors

The addressing space is a segment [0, 2n[

mii VRR 2,0,

mRR 2,0, 00 For the first node at t=0:For the first node at t=0:

The relative address E: identifies the relative location of the node ( ) ii RE


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Topology creationTopology creation

Node n first identifies its neighbors when it joins the network

Among these neighbors, the one which has the largest region will become the n's parent neighbor

The parent neighbor then gives to n a part of its own control region


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Topology creation (exTopology creation (exaample)mple)

a0

a1

0aA

0aL

1282,00a

01 aA

maaEL 2,0,0,

001

1a

p


23 Fdida


a0

a1 a2

642,00a

12864 2,21a


24 Fdida

9664 2,21a

642,00a


a0

a1 a2 a3

12896 2,22a


25 Fdida

11296 2,22a 9664 2,2

1a

642,00a


a0

a1 a2 a3

a4

128112 2,23a


26 Fdida

10496 2,22a 9664 2,2

1a

642,00a


a0

a1 a2 a3

a4an

128112112112104104 2,2,2,2,2,2nL

43 , aaAn

nap 128112 2,23a

112104 2,24a


27 Fdida

120112 2,23a

10496 2,22a 9664 2,2

1a

642,00a


a0

a1 a2 a3

a4an

112104 2,24a 128120 2,2

na


28 Fdida

Types of addressTypes of address

The universal identifier U The virtual identifier V

– Used for identifying a node's anchor– The Anchor node behaves as a Home Agent

for a set of nodes in its controlled region

The relative address E – Identifies a unique node in the logical network– Changes when node moves– Used for routing


29 Fdida

Locating nodesLocating nodes

The n's anchor is node h whose control region contains the virtual address Vn – Node h is identified by its relative address Eh

Node a wants to contact node b– a knows Vb=f(Ub)– a sends a search message to the neighbor whose control

region gets the message as close as possible to Vb

– The message is routed hop by hop until it reaches the node that contains Vb

The anchor node responds to a with a message containing the current b's relative address– Node b had already informed h about its current position


30 Fdida

Tribe register procedureTribe register procedure

a0

a1 a2 a3

a4

642,00a

9664 2,21a

112104 2,24a

10496 2,22a

128120 2,2na

120112 2,23a

an

nah

register

register

120102 22 nnn aaa RVU

1022)( nn aa VUf

962nah

1202naE


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Tribe location procedureTribe location procedure

a0

a1 a2 a3

a4

642,00a

9664 2,21a

112104 2,24a

10496 2,22a

128120 2,2na

120112 2,23a

an

1022)( nn aa VUf

nah

search


search


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located

located


a0

a1 a2 a3

a4

642,00a

9664 2,21a

112104 2,24a

10496 2,22a

128120 2,2na

120112 2,23a

an

1022)( nn aa VUf

nah



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data

data


a0

a1 a2 a3

a4

642,00a

9664 2,21a

112104 2,24a

10496 2,22a

128120 2,2na

120112 2,23a

an

1022)( nn aa VUf

nah


data

data


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Region continuityRegion continuity

Guarantee that an abandoned control region is taken over by a remaining node– The parent neighbor is responsible for

managing this region If the abandoned region can be merged

with the parent node’s region– OK!

If not– A region reassignement must be executed in

order to guarantee the region continuity


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MisroutingMisrouting

1282

23221442

1922

1762

232224 2,2nap

0 247244 2,2ja

244240 2,2na

an

2522

2482

2282

1602


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MisroutingMisrouting

1282

23221442

1922

1762

232224 2,2nap

0 247244 2,2ja

2522

2482

2282

1602


37 Fdida

ReferenceReference

Indirect Routing Using Distributed Location InformationViana Aline c., Dias de amorim Marcelo, Fdida Serge and Rezende José F. IEEE International Conference on Pervasive Computing and Communications (PerCom) Dallas-Fort Worth, Texas - March, 2003

http://www-rp.lip6.fr– publications

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Routing in Large-Scale Self-organized Networks