2. Agenda
1. Mobility Management in the Internet
2. Internet mobility overview
3. Problem in detail
4. Mobility management based on SDN
1. Existing research
2. Benefits of SDN based mobility
5. Software Defined Internet Mobility Management
1. Architecture overview
2. An open flow instantiation
3. Binding cache Placement Algorithm
1. Evaluation, experiment and results
6. Summary
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3. Mobility
Management in the
Internet
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• Along with the growing of mobile data services
efforts on Internet mobility have been paid
• So far there is no consensus
– Remains as an open issue
4. MMI and cellular networks
• Cellular networking has been providing mobility
• Why it may not suit Internet Mobility?
ISP handover
Inter device switching
• Trend to provide flexible & dynamic mobility management
• IP is considered as the core part of upcoming cellular networks
• LTE deployment has started in many markets: does not have circuit switched services
anymore
• Cellular networking is evolving toward IP- based designs (e.g. femtocells )
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5. Existing Internet Mobility solution
• Internet mobility = Uninterrupted internet connectivity
• Candidates: many IP mobility solutions
• IETF released standards that may be adopted into 3GPP: Proxy
Mobile IPv6 (EPC 3GPP)
• Challenge:
• Mobility contradicts current Internet architecture: Tight coupling
of higher layer protocols with IP address:
• TCP sessions are identified by Source-IP-add, Source-port, dest-IP add and dest
port
• Approach categories:
1. Routing based -> Keep IP address
2. Mapping based -> Use identifier to resolve locator (IP address):
Mobile IP protocols
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6. Integrating Internet mobility
management and SDN
• Despite of the various realizations of mobility management
they drawback different aspects: still an unsolved issue
• SDN emerging network architectural has a new approach:
• Network structures, functions and performance are defined simpler
thanks to programmable devices and centralized control logic
• Network features required to support IP mobility can also be
realized in software defined ways.
• Open Flow the most well known instantiation of SDN
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7. SDN helps to solve IP mobility
protocols problems ?
• Programmable devices provide flexibility
• Centralized control enables awareness of all mobility details
• IP mobility may require less host involvement under SDN
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9. Internet mobility overview
1. Mobile IP
• IETF standards
- Many derivatives (PMIP v6 )
- Standardization began two decades ago
2. Identifier/Locator Split ( ILS ) designs
• Relies on hosts to realize mobility management
• An IP address has embedded both identifier and locator
- A concept also discussed widely in past decades
3. Other proposals on future Internet Architecture
• Substantial changes to the current Internet
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10. MobileIP&derivatives
• Minimal Handover Latency
• No client software requirement ( in the case
of PMIPv6)
• Extremely Light Weight Protocol, MAG
function can be implemented on a low-cost
access point
• MIP centralizes mobility signalling and
forwarding -> single Home Agent (HA)
• Increase signalling cost when out Home
network
• All packets from CN to MN have to go
through HA -> Triangle routing problem
• Thus heavy load for HAs
• Distributed Mobility Management (DMM)
• Multiple mobility anchors
• HoA not a fixed location any more
*Under standardization
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11. 1. ILS designs
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• Two categories:
– Separate edge and core add name spaces. Focused in
global routing *
– Entire IP space as locators: A namespace for identifiers
• Host based solutions (mobility
implemented at host side)
• Either introduce a new layer or modify
existing layer
• Host Identity Protocol (HIP)= DNS +
Rendezvous -> new layer above network
layer
• Identifier/Locator Network Protocol (ILNP) =
Split IP ->Modifies transport layer
• Name Based Sockets (NBS) = Domain
names ID-> new layer above transport layer
• LISP Mobile Node= Endpoint ID and Routing
locators (RLOC)->Lightweight tunnel routing
on each mobile host (avoids use of DNS)
*These are not in the scope of this slides
The same idea with different
formatting, implementation
and mapping functions
13. Mobility management analysis
Considering handoff management:
• Three categories:
• Local scope handoff : MIPs
• Global scope handoff : ILS designs
• Hybrid: DMM solutions *(under standardization at IETF)
• Local scope handoff :propagate mapping to close HA
• Global scope handoff: propagate globally if HA has changed
• Packets are forwarded to an intermediary node close to MN
Similarities: All of them require MN to announce its up to date mapping to network
so that CN can reach it , directly(ILS) or indirectly (MIP)
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14. Routing path stretch and handoff
efficiency
Trade off between routing path stretch and hand off latency
• Limited scope of mapping announcement reduce signalling
overhead and latency but CN loses exact location and has to
reach MN via indirection which may lead to routing path stretch.
• Mobile IP leads to routing path stretch (e.g. triangle routing)
• ILS heavy overhead and large latency
• DMM a balanced option? (Last draft: 2015-04-22 )
• Future mobile users connect simultaneously to multiple ISP and switch between
them.
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15. Mobility management based on SDN
Existing research
• Open Roads
• Improve robustness of handoff with multicast Open Flow
• Improving basic IP mobility functions adopted by existing
protocols
• SDN/Open Flow in Virtualized LTE to support distributed
mobility management
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16. Benefits of SDN based mobility
1. Existing solutions with different trade-offs, and not really
flexible
2. A promising way to seek balance for the performance of the
trade off
3. Programmable devices are enabled as potential rendezvous
for MNs
1. No performing mapping announcement in arbitrary scope
2. Centralized control can define the scope
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17. Software Defined Internet Mobility
Management
The important for SDIMM:
Seek an algorithm that optimizes the
scope of mapping announcements
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18. • Architecture overview
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– Identifiers as in ILS
» Any format but a field in
packet devices can
recognize
– Locators of MNs
» IP address, normally
– Two control plane sub
functions:
» SDN controllers collect
current location of MN
» SDN controllers download
mapping in relevant SDN
devices (on request or
update)
20. Protocol basis
1. Locator ( CoA )
• IP address
2. Identifier ( HoA )
• IP address
3. OpenFlow controller
maintains binding cache
4. OpenFlow switches
1. Maintain replica of binding
cache
2. Redirect packets to MN
according flow table
• Inter domain handoff: long
distance, tringle and the
optimize
• Short distance: single logic
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21. Binding Cache Placement Algorithm
But in which switch (TS) place cache binding
• MN’s first hop = Triangle routing (like MIP)
• CN’s first hop = Large number of flow table download and
high latency (like HIP)
=>Binding Cache Placement Problem
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23. 1. Evaluation
1. Algorithm proposed, assuming:
1. Intra domain scenario
2. MN to CN only relies in destination address
2. Algorithm random for each path pair of previous and current
path chose randomly any switch
3. Algorithm CN, For each pair of paths choose CN’s first hop
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27. Conclusion
Experiment show advantage of SDN architecture due to:
• Centralized control
• Programmable devices
• In general SDN enables flexibility
• => Adaptive to various scenarios in future
mobile Internet
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