Transcript ROB: Route Optimization Assisted by BGP

GLOBECOM 2007
Route Optimization
for Large Scale Network Mobility
Assisted by BGP
Feriel Mimoune,
Farid Nait-Abdesselam,
Tarik Taleb and
Kazuo Hashimoto
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Outline
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Introduction
Related Work
ROB: Route Optimization Assisted By BGP
Performance Analysis
Conclusion
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Introduction
• Considering mobility of an entire network,
– it is possible to use Mobile IP to enable mobility for all the
devices within the mobile network.
– However, this would
• require all the devices to be Mobile IP capable and
• will incur significant overhead,
– i.e, a storm of control packets as every device has to perform Mobile
IP functions.
• In this paper, we discuss the design of a new
scheme to enable IPv6 mobile networks
– to perform route optimization by invoking the widely
deployed border gateway protocol (BGP).
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Related work
• The Optimized Route Cache (ORC) scheme
– proxy routers intercept packets, destined to the target
network prefixes, using the Interior Gateway Protocol (IGP)
in the Autonomous System (AS).
• then encapsulate the packets and tunnel them to the corresponding
MRs.
– the upper routers, in the nested mobile network, are
• aware of the network prefix information of lower routers and
• designed to send them to their ORC (proxy) routers.
– modifies the route advertisement (RA) message
» fixed routers should be also modified
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Related work (cont.)
• The NEMO basic support
– a bidirectional tunnel between MR and its correspondent
HA
• MR’s HA intercepts all packets directed to MNNs (Mobile Network
Nodes) and tunnels them toward the MR
• MNNs outbound packets are also tunneled to the HA in order to
bypass ingress filtering
– simple and provides complete and transparent mobility to
MNNs
triangular suboptimal routing
HA becomes the bottleneck
data packets of nested mobile networks experience pinball routing and multiple encapsulations.
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Related work (cont.)
• Reverse Routing Header (RRH)
– record addresses of intermediate MRs into the packet
header
• only one bidirectional tunnel between the first MR and its HA
• avoid packet delivery through all HAs of the intermediate MRs
– Although the authors claim that this scheme performs route
optimization between a CN and a MR, there is no detailed
description on the route optimization operation.
Suffers from lack of a secured binding update mechanism
using RRH and
has to modify the RA messages to count the number of
intermediate MRs
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ROB: Route Optimization Assisted by
BGP
• BGP is a highly robust and scalable routing protocol, as
evidenced by its wide use in the Internet.
– An entry in the BGP routing table (Network, Next Hop, Path)
• Network field: the network destination address.
• Next Hop field: the BR’s IP address that should be used as the next hop.
• Path field: composed of a sequence of autonomous system path segments
– When changes to the routing table are detected, the BGP routers send
information on only changed routed to their neighbors.
• We upgrade the entry of the routing table by one more field
related to the temporary network prefix (TNP) as (Network,
Next Hop, Path, TNP).
– MR gets a new TNP at the new location
– TNP is advertised by MR, to each MNN by sending a RA message.
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ROB: Route Optimization Assisted by
BGP (cont.)
• The goal is
– to enable mobile networks to seamlessly change their point
of attachment to the Internet
• while maintaining an efficient routing optimization between any pair
of MNN and CN.
– to reduce the number of signaling messages that could be
generated,
– to improve the quality of service in term of delays,
– to preserve established sessions without deploying other
additional entities, and
– to solve the triangle or dog-leg routing problem
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ROB – Location Registration Process
• When a mobile network changes its point of
attachment to the Internet, it first gets a topologically
correct
– CoA for its egress interface,
– new TNP from the visited AR.
• advertises the delegated prefix to its subnet by sending a RA
• enables each mobile network node to build its CoA
• The MR advertises this TNP to its home network’s
border router, which will
– update its BGP routing table and
– send the updates to its border router peers.
• according to the standard BGP’s behavior.
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of MR
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ROB – Communication Procedure
• communication starts from a MNN
– it sends packets using its CoA as source address.
• communication process is initiated by any CN
– receives the home address of the MNN by means of DNS
request
– sends its first packets toward the nearest border router
(BR3) within its AS
• be routed to the home AS using the home mobile network prefix
(MNP)
• assume that these first packets are tunneled by the home agent
(HA) to the current location of mobile network,
– e.g. using NEMO basic support protocol
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– the BR3 advertise the CN with the new location of the
MNN,
• By sending him the new TNP related to MNN’s new location.
– CN forms the corresponding couple (MNN address-CoA)
and sends the following packets using the CoA as
destination address
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• a typical format of the update message used to advertise both
BR and CN of the new location of the mobile network
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Performance Analysis
– Analytical Analysis
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[3, 5]ms
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Performance Analysis
– Simulation Analysis
• Use OPNET Modeler
– CBR, 200kbps, between CN and MNN (CN to MNN)
– A background traffic is injected within the network
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Conclusion
• a route optimization scheme assisted by BGP is proposed for
large scale? network mobility
– improves quality of service in terms of bandwidth usage and end to
end delays
• few modifications in the BGP routing tables
– TNP update message, CN operation
• Analytical and simulation results show that ROB scheme
outperforms the NEMO Basic Support scheme in terms of
communication delays.
– may incur a small control message overhead within the core network
• Future work
– investigate the impact of this control packet overhead
– Nested network mobility
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Comments
• ROB scheme indeed achieves route optimization
– topologically correct CoA
– For IPv6 nodes
• But handover delay…
– Can established sessions really be preserved?
• Their analytical analysis method is simple, but is
acceptable in GLOBECOM
• Reducing additional entity (function) helps when
deploying
– Tradeoff
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