on the cost of supporting multihoming and mobility
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On the Cost of Supporting Multihoming and Mobility. Ibrahim Matta Computer Science Boston University Joint work with Vatche Ishakian, Joseph Akinwumi, John Day. Mobility = Dynamic Multihoming. Hosts / ASes became increasingly multihomed Multihoming is a special case of mobility - PowerPoint PPT PresentationTRANSCRIPT
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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
I. Matta
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
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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