Transcript Comparison of IP Micromobility Protocol

Comparison of IP
Micromobility Protocol
Wireless/Mobile Network Lab
이진우
Contents
 Introduction
 Classification of protocols
 A Generic Model
 Simulation Model
 Handoff Quality
 Route Control Messaging
 Improved Handoff Schemes
 Conclusion
Introduction
 Micormobility protocols

Motivation




Predominance of pico-cellular environment in the future – small cell size, large
number of access points
Efficiency problem of Mobile IP for real-time application within a single domain :
high handoff latency, high signaling overhead and transient packet loss
No paing capability in Mobile IP
Main functions

Path setup mechanism, Fast handoff mechanism, Paging mechanism
 Presentation

Performance comparison of CIP(Cellular IP), Hawaii, Hierarchical Mobile
IP(HMIP) based on the Columbia IP Micromobility Software(CIMS) ns-2
extension
Classification of protocols
 Hierarchical Tunnel-based Approach

Location database is maintained in a distributed form by set of FAs
in the
access network
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Tunneling corresponding to FA toward MH’s AP
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BCMP, IDMP, 3G UMTS/CDMA2000, HMIP
 Mobile-Specific Routing Approach

Avoidance of the overhead introduced by decapsulation and reencapsulation
schemes without tunneling and address conversion
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Use home address and co-located COA in access network
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Cellular IP, Hawaii
Figure 1. Two approach
Hierarchical Tunneling Approach
Mobile-Specific Routing Approach
A Generic Model (Cont.)

The use of MRP (mobile routing point)
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MSR to refer to nodes that participate in the
procedure
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Each MSR contains a list of hosts whose data
path traverses the MSR

Figure 2-a
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Data packet addressed to MH0 are forwarded
by using “IP-in IP” encapsulation


Use Hierarchical tunneling such as HMIP
Figure 2-b
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Internal address (MH0’s identifier) remain
unchanged while external address (the next
MRP’s address) is replaced by each MRP

IP Packets are encapsulated in L2 frames such
as CIP and Hawaii
Figure 2 : a) A network of mobile routing points ;
b) a full network with intermediate nodes
A Generic Model
<Mapping of micromobility protocols to the generic micormobility model based on MRPs>
<Micromobility protocols grouped by the MPR protocol layer>
Simulation Model
 CIMS ( Columbia IP Micromobility
Software)
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Micromobility extension for the ns-2 network
simulator
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Support separate models for CIP, Hawaii,
HMIP
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Hawaii
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CIP : Hard and semisoft handoff, Paging and
security
Hawaii : UNF (unicast nonforwarding) and
MSF (multiple stream forwarding) handoff
BaseStatioinNode object instead of AP
Hawaii router are implemented in special
HawaiiAgent object
HMIP

Use a GFAAgent object to implement a single
GFA and FAs in each AP
Figure 3. The simulated network topology
Handoff Quality (Cont.)
 UDP
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MH moves periodically between
neighboring AP at a speed of 20 m/s

Use UDP probing traffic between CH
and MH and count the average
number of packet loss during handoff
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Results of Figure 4
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CIP hard handoff and Hawaii UNF
are very similar and handoff delay is
related to the packet delay between
the APs and the cross-over node
HMIP cannot benefit from crossover
distance
Figure 4. UDP packet loss at handoff
Handoff Quality
 TCP
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At 14.75s into the simulation a
CIP hard handoff occurs

Packet loss caused by the handoff
results in a TCP timeout
Figure 5. TCP sequence numbers at the
time of CIP hard handoff
Route Control Messaging
 According to Tree topologies

CIP and Hawaii are similar for tree
topologies
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Difference for non-tree topologies


Suboptimal in Hawaii
Optimal in CIP
 Trade-off of suboptimal routing
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Cause performance bottleneck and
signaling load at the common section
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Discard update message at crossover
MRP
Improved Handoff Schemes (Cont.)
 Packet loss reduction techniques
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Bi-casting techniques of CIP
Semisoft handoff by allowing a MH to set up routing to new AP prior to
handoff
 Delay device for a fixed period amount of time (Tss) before transmission
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Buffering and forwarding techniques of Hawaii
MSF operates after handoff
 Old AP forwards packet to new AP during handoff
 Store all packet received for a certain period (Tmsf)
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HMIP
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Operate along similar lines, bi-casting and buffering and forwarding
Improved Handoff Schemes (Cont.)
CIP semisoft handoff
Hawaii MSF handoff
Figure 8. UDP packet loss and duplication ; this is for packet interarrival times of 5 ms and 10 ms
Improved Handoff Schemes (Cont.)
semi-soft handoff (Tss = 50 ms)
semi-soft handoff (Tss = 100 ms)
Figure 9. TCP sequence numbers at the time of a Cellular IP
Improved Handoff Schemes
 Difference between CIP and Hawaii
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Packet reordering
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TCP protocol reacts adversely to
Hawaii MSF
 NewReno congestion control
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Applying NewReno congestion
control represents a different
approach to improving handoff
performance
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NewReno can be advatageous in
case of batch losses due to radio
fading
Figure 6. Application level TCP throughput in
periodic handoffs
Conclusion
 Open issue

Support the delivery of a variety of traffic including best effort and
real-time traffic

Work on a suitable QoS model for micromobility
 Working group
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IETF Mobile IP WG
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IETF Seamoby WG

Low-latency handoff, IP paging