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On the Cost of Supporting Multihoming and Mobility

Ibrahim MattaComputer ScienceBoston University

Joint work with Vatche Ishakian, Joseph Akinwumi, John Day

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Mobility = Dynamic Multihoming Hosts / ASes became increasingly multihomed

Multihoming is a special case of mobility

RINA (Recursive InterNetwork Architecture) is a clean-slate design – http://csr.bu.edu/rina

RINA routing is based on node addresses Late binding of node address to point-of-attachment

Compare to LISP (early binding) and Mobile-IP Average-case communication cost analysis Simulation over Internet-like topologies

What’s wrong today?

Network

Transport

Data Link

Physical

Applications

Network

Transport

Data Link

Physical

Applications

Network

DL DL

PHY PHY

Web, email, ftp, …

We exposed addresses to applications We named and addressed the wrong things

www.cs.bu.edu128.197.15.10

128.197.15.

1

128.

10.1

27

.25

128.10.0.0 128.197.0.0

RINA offers better scoping

Network

Transport

Data Link

Physical

Applications

Network

Transport

Data Link

Physical

Applications

Network

DL DL

PHY PHY

TCP, UDP, …

IP

Web, email, ftp, …

IPC

IPC IPC

E2E (end-to-end principle) is not relevant Each IPC layer provides service / QoS over its scope

IPv6 is/was a waste of time! We don’t need too many addresses within an IPC layer

5

RINA: Good Addressing

Destination application is identified by “name” App name mapped to node name (address) Node addresses are private within IPC layer

Need a global namespace, but not address space Destination application process is assigned a port

number dynamically

BA

I1 I2

want to send message to “Bob”

IPC Layer

To: B

“Bob”B

Bob

IPC Layer

6

RINA: Good Addressing

Late binding of node name to a PoA address PoA address is “name” at the lower IPC level Node subscribes to different IPC layers

BA

I1 I2

want to send message to “Bob”

BI2

To: B

Bob

IPC Layer

IPC Layer

B, , areIPC processeson same machine

I1 I2

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RINA: Good Routing

Back to naming-addressing basics [Saltzer ’82] Service name (location-independent) node name (location-dependent) PoA address (path-dependent) path

We clearly distinguish the last 2 mappings Route: sequence of node names (addresses) Map next-hop’s node name to PoA at lower IPC level

source destination

8

Mobility is Inherent

Mobile joins new IPC layers and leaves old ones Local movement results in local routing updates

CHMH

9

Mobility is Inherent

Mobile joins new IPC layers and leaves old ones Local movement results in local routing updates

CH

10

Mobility is Inherent

Mobile joins new IPC layers and leaves old ones Local movement results in local routing updates

CH

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Compare to loc/id split (1) Basis of any solution to the multihoming issue Claim: the IP address semantics are overloaded as

both location and identifier LISP (Location ID Separation Protocol) ‘06

EIDx EIDy

EIDx -> EIDy

EIDx EIDy

RLOC1x RLOC2y

Mapping: EIDy RLOC2y

Compare to loc/id split (2) Ingress Border Router maps ID to loc, which is the

location of destination BR Problem: loc is path-dependent, does not name the

ultimate destination EIDx -> EIDy

EIDx EIDy

RLOC1x RLOC2y

Mapping: EIDy RLOC2y

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LISP vs. RINA vs. … Total Cost per loc / interface change = Cost of Loc / Routing Update +

[Pcons*DeliveryCost + (1-Pcons)*InconsistencyCost]

expected packets per loc changePcons: probability of no loc change since last pkt delivery

RINA’s routing modeled over a binary tree of IPC layers: update at top level involves route propagation over the whole network diameter D; update at leaf involves route propagation over D/2h, h is tree height

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LISP

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LISP

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RINA

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RINA

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RINA

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MobileIP

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LISP vs. RINA vs. …

RINA

8x8 Grid TopologyRINA uses 5 IPC levels; on average, 3 levels get affected per move

LISP

Simulation: Packet Delivery Ratio

BRITE generated 2-level topology

Average path length 14 hops

Random walk mobility model

Download BRITE from www.cs.bu.edu/brite

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RINA

LISP

Simulation: Packet Delay

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LISP

RINA

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Bottom Line: RINA is less costly

RINA inherently limits the scope of location update & inconsistency

RINA uses “direct” routing to destination node

More work: prototyping

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RINA papers @http://csr.bu.edu/rina

Thank You

Questions?