Comparison of IP Micromobility Protocol

Comparison of IP Micromobility Protocol

Wireless/Mobile Network Lab

이 진 우

ContentsContents

Introduction Classification of protocols A Generic Model Simulation Model Handoff Quality Route Control Messaging Improved Handoff Schemes Conclusion

IntroductionIntroduction

Micormobility protocols

Motivation Predominance of pico-cellular environment in the future – small cell size, large num

ber of access points Efficiency problem of Mobile IP for real-time application within a single domain : h

igh 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 extens

ion

Classification of protocolsClassification of protocols

Hierarchical Tunnel-based Approach

Location database is maintained in a distributed form by set of FAs in the ac

cess network

Tunneling corresponding to FA toward MH’s AP

BCMP, IDMP, 3G UMTS/CDMA2000, HMIP

Mobile-Specific Routing Approach

Avoidance of the overhead introduced by decapsulation and reencapsulation sc

hemes without tunneling and address conversion

Use home address and co-located COA in access network

Cellular IP, Hawaii

Figure 1. Two approachFigure 1. Two approach

Hierarchical Tunneling Approach

Mobile-Specific Routing Approach

A Generic Model (Cont.)A Generic Model (Cont.)

The use of MRP (mobile routing point)

MSR to refer to nodes that participate in the pro

cedure

Each MSR contains a list of hosts whose data pa

th traverses the MSR Figure 2-a

Data packet addressed to MH0 are forwarded by

using “IP-in IP” encapsulation

Use Hierarchical tunneling such as HMIP Figure 2-b

Internal address (MH0’s identifier) remain unch

anged while external address (the next MRP’s a

ddress) is replaced by each MRP

IP Packets are encapsulated in L2 frames such a

s CIP and Hawaii Figure 2 : a) A network of mobile routing points ; b) a full network with intermediate nodes

A Generic ModelA Generic Model

<Mapping of micromobility protocols to the generic micormobility model based on MRPs>

<Micromobility protocols grouped by the MPR protocol layer>

Simulation ModelSimulation Model

CIMS ( Columbia IP Micromobility Software)

Micromobility extension for the ns-2 network

simulator

Support separate models for CIP, Hawaii, HM

IP CIP : Hard and semisoft handoff, Paging and se

curity Hawaii : UNF (unicast nonforwarding) and MS

F (multiple stream forwarding) handoff

Hawaii BaseStatioinNode object instead of AP Hawaii router are implemented in special Hawa

iiAgent 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.)Handoff Quality (Cont.)

UDP

MH moves periodically between neig

hboring AP at a speed of 20 m/s

Use UDP probing traffic between CH

and MH and count the average numb

er of packet loss during handoff

Results of Figure 4 CIP hard handoff and Hawaii UNF ar

e 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 Handoff Quality

TCP

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 MessagingRoute Control Messaging

According to Tree topologies

CIP and Hawaii are similar for tree

topologies

Difference for non-tree topologies Suboptimal in Hawaii Optimal in CIP

Trade-off of suboptimal routing

Cause performance bottleneck and

signaling load at the common section

Discard update message at crossover

MRP

Improved Handoff Schemes (Cont.)Improved Handoff Schemes (Cont.)

Packet loss reduction techniques

Bi-casting techniques of CIP Semisoft handoff by allowing a MH to set up routing to new AP prior to h

andoff Delay device for a fixed period amount of time (Tss) before transmission

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)

HMIP Operate along similar lines, bi-casting and buffering and forwarding

Improved Handoff Schemes (Cont.)Improved Handoff Schemes (Cont.)

Figure 8. UDP packet loss and duplication ; this is for packet interarrival times of 5 ms and 10 ms

CIP semisoft handoff Hawaii MSF handoff

Improved Handoff Schemes (Cont.)Improved Handoff Schemes (Cont.)

Figure 9. TCP sequence numbers at the time of a Cellular IP

semi-soft handoff (Tss = 50 ms) semi-soft handoff (Tss = 100 ms)

Improved Handoff SchemesImproved Handoff Schemes

Difference between CIP and Hawaii

Packet reordering

TCP protocol reacts adversely to Ha

waii MSF NewReno congestion control

Applying NewReno congestion cont

rol represents a different approach to

improving handoff performance

NewReno can be advatageous in cas

e of batch losses due to radio fading Figure 6. Application level TCP throughput in periodic handoffs

ConclusionConclusion

Open issue

Support the delivery of a variety of traffic including best effort and rea

l-time traffic

Work on a suitable QoS model for micromobility

Working group

IETF Mobile IP WG

IETF Seamoby WG Low-latency handoff, IP paging