Daedalus/GloMop Architectural...

Daedalus/GloMop Daedalus/GloMop Architectural WalkthroughArchitectural Walkthrough

Daedalus Retreat, Lake TahoeDaedalus Retreat, Lake Tahoe

June 18-20th, 1996June 18-20th, 1996

Steve Gribble and Todd HodesSteve Gribble and Todd Hodes{gribble,hodes}@cs.berkeley.edu{gribble,hodes}@cs.berkeley.edu

OutlineOutline

•• Motivation and overviewMotivation and overview

•• Core architecture componentsCore architecture components

•• Core architecture walkthroughCore architecture walkthrough–– connection, document retrieval, vertical handoff, connection, document retrieval, vertical handoff,

document refinementdocument refinement

•• Extended architecture componentsExtended architecture components

•• Extended architecture walkthroughExtended architecture walkthrough–– connection and authentication, vertical handoff, connection and authentication, vertical handoff,

horizontal handoff, dynamic adaptation, load horizontal handoff, dynamic adaptation, load balancing, domain and network servicesbalancing, domain and network services

•• Summary, Open IssuesSummary, Open Issues

Daedalus/GloMop Architectural Walkthrough - June, 1996Daedalus/GloMop Architectural Walkthrough - June, 1996

MotivationMotivation

•• mobility-aware network servicesmobility-aware network services–– seamless roaming (overlay IP)seamless roaming (overlay IP)–– efficiency of protocols and of handoffefficiency of protocols and of handoff

•• mobility-aware application servicesmobility-aware application services–– dynamic adaptation to variabilitydynamic adaptation to variability–– enable a wide array of client devicesenable a wide array of client devices

•• mobility-aware domain servicesmobility-aware domain services–– resource discoveryresource discovery–– load balancingload balancing–– meteringmetering


ChallengesChallenges

•• cohabitate with existing infrastructurecohabitate with existing infrastructure–– Mobile IP, TCP, HTTP, Kerberos, ...Mobile IP, TCP, HTTP, Kerberos, ...–– justify custom protocolsjustify custom protocols

•• a scalable architecturea scalable architecture–– network and proxies should support many clientsnetwork and proxies should support many clients

•• integrable but independent componentsintegrable but independent components–– pieces of the architecture should be able to function pieces of the architecture should be able to function

on their ownon their own–– integration yields optimization and new capabilityintegration yields optimization and new capability


The Daedalus/GloMop ArchitectureThe Daedalus/GloMop Architecture

GloMop

App

NCM

Proxy

proxy host

NCM

Distillers

corresponding host

Authentication

Subnet Manager

Metering & Credit

Resource Manager

Foreign agent

CB

Q

base stations

PTM

snoo

p

content server

CBQagent

Han

doff

cont

rolle

r

delivery class abstraction

deca

pd

beacond

Mobility Database

domain services

subnet services

mobile host

OutlineOutline










Core Architecture ComponentsCore Architecture Components

mobile host

corresponding host

content server

ApplicationSupport

CustomMH

NetworkStack

proxy host / HA

Proxy

UnmodifiedNetwork

Stack

base station / FA

CustomBS

NetworkStack


Core Daedalus Mobile Host ComponentsCore Daedalus Mobile Host Components

. . .

RFIR

Overlay IP

TCP / UDP

Unmodified App

ControlPanel

ControlInterface

Application, Presentation,

SessionLayers

TransportLayer

NetworkLayer

Data LinkLayer

mobile IP

multiple interfaces

handoff controller


Core Daedalus Base Station ComponentsCore Daedalus Base Station Components

. . .

RFEthernet

Overlay IP

ControlInterface

NetworkLayer

Data LinkLayer

TCPSnoop

mobile IP,decapsulation

wireless and wired interfacesbe

acon

d


Core Architecture ComponentsCore Architecture Components

mobile host

corresponding host

content server

ApplicationSupport

CustomMH

NetworkStack

proxy host / HA

Proxy

UnmodifiedNetwork

Stack

base station / FA

CustomBS

NetworkStack


Core Proxy ArchitectureCore Proxy Architecture

Distiller

Proxycontentserver

mobile proxy

unmodifiedapplicationcontrol

panel

TCP/UDP

overlay IP

controlinterface

IR RF ...

TCP/UDP

IP

Ethernet

application-specificprotocol

NOW

(ove

rlay

)IP

OutlineOutline










Connecting to the Network Connecting to the Network (core architecture - Mobile IP)(core architecture - Mobile IP)

mobile host

base station

ICMP routeradvertisement

unmodifiedapplication

controlpanel

TCP/UDP

Overlay IP

controlinterface

IR RF . . .

Overlay IP

controlinterface

beac

ond

Ether RF . . .

snoop

foreign agent

Mobile IP

Ethernet

home agent

Mobile IP

Ethernet



mobile host

base station


controlpanel

TCP/UDP

Overlay IP

controlinterface

IR RF . . .

Overlay IP

controlinterface

Ether RF . . .

snoop

registrationrequest

newcare-of address

foreign agent

Mobile IP

Ethernet

home agent

Mobile IP

Ethernet

beac

ond



mobile host

base station


controlpanel

TCP/UDP

Overlay IP

controlinterface

IR RF . . .

Overlay IP

controlinterface

Ether RF . . .

snoop

registrationreply

foreign agent

Mobile IP

Ethernet

home agent

Mobile IP

Ethernet

beac

ondregistration

reply


Document RequestDocument Request

Distiller

Proxy contentserver

mobile proxy

controlpanel

TCP/UDP

IP

Ethernet

HTTP“get”

HTTP“get”

webbrowser

TCP/UDP

overlay IP

controlinterface

IR RF ...


Document Download and ‘Chunking’Document Download and ‘Chunking’

Distiller

mobile

controlpanel

Proxy contentserver

proxy

TCP/UDP

IP

Ethernet

HTTPwebbrowser

TCP/UDP

overlay IP

controlinterface

IR RF ...


DistillationDistillation

Distiller

mobile

controlpanel

Proxy contentserver

proxy

TCP/UDP

IP

Ethernet

webbrowser

TCP/UDP

overlay IP

controlinterface

IR RF ...


Document UploadDocument Upload

Distiller

mobile

controlpanel

Proxy contentserver

proxy

TCP/UDP

IP

Ethernet

HTTP

webbrowser

TCP/UDP

overlay IP

controlinterface

IR RF ...


Vertical Handoff from IR to WaveLANVertical Handoff from IR to WaveLAN(core architecture)(core architecture)

!

mobile host


controlpanel

TCP/UDP

Overlay IP

controlinterface

IR RF . . .

new base station

Overlay IP

controlinterface

beac

ond

Ether RF . . .

snoop

old base station

Overlay IP

controlinterface

beac

ond

Ether RF . . .

snoop


Handoff SubroutineHandoff Subroutine(core architecture)(core architecture)

old bs

Home agent

new bs

registrationrequest

mobile host


TCP/UDP

Overlay IP

controlinterface

IR RF . . .

new care-of address

Foreign agent

controlpanel

registrationrequest



old bs

Home agentForeign agent

new bsacknowledgement

mobile host


controlpanel

TCP/UDP

Overlay IP

controlinterface

IR RF . . .



old bs

Home agentForeign agent

new bs

de-register

mobile host


TCP/UDP

Overlay IP

controlinterface

IR RF . . .

controlpanel


Handoff Notification and Dynamic Handoff Notification and Dynamic AdaptationAdaptation

Distiller

mobile

controlpanel

Proxy contentserver

proxy

TCP/UDP

IP

Ethernet

UDPpacket

manualhandoff

command

webbrowser

TCP/UDP

overlay IP

controlinterface

IR RF ...

(average) networkcharacteristics


‘Chunk’ Refinement‘Chunk’ Refinement

Distiller

mobile

controlpanel

Proxy contentserver

proxy

TCP/UDP

IP

Ethernet

refinementrequest

HTTP “get”webbrowser

TCP/UDP

overlay IP

controlinterface

IR RF ...

OutlineOutline










Extended Architecture ComponentsExtended Architecture Components

mobile host

corresponding host

content server

ApplicationSupport

CustomMH

NetworkStack

proxy host / HA

Proxy

CustomProxy

NetworkStack

base station / FA

CustomBS

NetworkStack


Extended Daedalus Mobile HostExtended Daedalus Mobile Host

. . .

RFIR

Dynamic Allocation Agent

Overlay IP

TCP / UDP

Unmodified App

GloMop

GloMopApp

ControlPanel

ControlInterface


SessionLayers

TransportLayer

NetworkLayer

Data LinkLayer

handoff controller

multiple interfaces

networkconnection monitor

mobile IP

DeliveryClasses

UDP


Extended Daedalus Base StationExtended Daedalus Base Station

. . .RFEthernet

Dynamic Allocation (Class-Based Queuing)

Overlay IP

ControlInterface

NetworkLayer

Data LinkLayer

mobile IP,decapsulation,

multicast handoff buffers

wired and unwired interfacesbe

acon

d

deca

pd

TCPSnoop


Extended Daedalus ProxyExtended Daedalus Proxy

Ethernet

Overlay IP

TCP / UDP

Proxy

ControlInterface


SessionLayers

TransportLayer

NetworkLayer

Data LinkLayer

network connection monitor

DeliveryClasses

UDP


Extended Service ArchitectureExtended Service Architecture

proxy host

corresponding host

Authentication

Subnet Manager

Metering & Credit

Resource Manager

base stations

Mobility database

Foreign agent

mobile host

subnet services

domain services


Extended proxy architectureExtended proxy architecture

Distiller

HT

TP

mobile proxy

unmodapp

TCP/UDP

Ethernet

NOW

TCP/UDP

overlay IP

deliv.classes

controlinterface

IR RF ...cbq

GloMop

GloMopapp

PTM

PO

P3

Glo

Mop

Proxy

delivclass co

ntro

lin

terf

.

cont

rol

pane

l

(ove

rlay

)IP

overlay IP

OutlineOutline










Connecting to the Network Connecting to the Network (Multicast)(Multicast)

mobile host

base station / FA

UDP packet

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

home agent

Overlay IP

Ethernet

Subnet manager

Mobility database

Metering & Credit

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

deca

pd

beac

ond



mobile host

base station / FA

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

home agent

Overlay IP

Ethernet

Subnet manager

Mobility database

Metering & Credit

register;join multicast group;

start forwarding

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

classstructure

deca

pd

beac

ond

care-ofaddress



mobile host

base station / FA

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

home agent

Overlay IP

Ethernet

Subnet manager

Mobility database

Metering & Credit

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

deca

pd

beac

ond

ack

ack



mobile host

base station / FA

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

deca

pd

beac

ond

snoop

home agent

Overlay IP

Ethernet

Subnet manager

Mobility database

Metering & Creditregistration

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ


Connecting to the NetworkConnecting to the Network (Hybrid) (Hybrid)

mobile host

base station

ICMP routeradvertisement

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

Subnet manager

Mobility database

Metering & Credit

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

registrationrequest

foreign agent

Overlay IP

Ethernet

home agent

Mobile IP

Ethernet

care-of addressupdate

deca

pd

beac

ond



mobile host

base station

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

Subnet manager

Mobility database

Metering & Credit

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

allocatedmulticastaddress

foreign agent

Overlay IP

Ethernet

home agent

Mobile IP

Ethernet

ack

deca

pd

beac

ond



mobile host

base station

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

Subnet manager

Mobility database

Metering & Credit

join multicast group;start forwarding

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

classstructure

foreign agent

Overlay IP

Ethernet

home agent

Mobile IP

Ethernetde

capd

beac

ond



mobile host

base station

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .

Overlay IP

controlinterface

snoop

Subnet manager

Mobility database

Metering & Credit

registration

CBQ Agent

deliv. classes

GloMop

GloMopapp

IR RF . . .CBQ

foreign agent

Overlay IP

Ethernet

home agent

Mobile IP

Ethernetde

capd

beac

ond


Kerberos AuthenticationKerberos Authentication

•• centralized, secure database (centralized, secure database (KDCKDC) holds secrets () holds secrets (DES DES keykey) only known by ) only known by principlesprinciples

•• to access Kerberized to access Kerberized servicesservices, principles are issued , principles are issued ticketstickets for those services by the ticket-granting server for those services by the ticket-granting server ((TGSTGS))

•• a ticket for the ticket-granting server (a ticket for the ticket-granting server (TGTTGT) is issued ) is issued by the KDCby the KDC

•• the TGT is encrypted with the issuee’s secretthe TGT is encrypted with the issuee’s secret

•• tickets contain tickets contain session keyssession keys


Authenticated Proxied ServicesAuthenticated Proxied Services

•• proxies are treated as principlesproxies are treated as principles

•• clients access proxies by gaining tickets for their clients access proxies by gaining tickets for their servicesservices

•• cross-domain authentication is possible by having a cross-domain authentication is possible by having a foreign TGS listed as a principle in the local systemforeign TGS listed as a principle in the local system

•• CharonCharon is a protocol that enables Kerberos for is a protocol that enables Kerberos for impoverished clientsimpoverished clients

•• CharonCharon also enables “indirect authentication” also enables “indirect authentication”


Charon Authentication:Charon Authentication:Obtaining TGT for Visited ProxyObtaining TGT for Visited Proxy

Visited ProxyGloMop Home Proxy

HomeKDC

HomeTGS

VisitedKDC

VisitedTGS

Home TGTrequest

Home TGTrequest

Home TGTrequestHome TGT

Home TGTHome TGT

DNS

find proxyrequestproxy address


Charon Authentication:Charon Authentication:Obtaining TGT for Visited ProxyObtaining TGT for Visited Proxy


HomeKDC

HomeTGS

VisitedKDC

VisitedTGS

Visited TGTrequest

Visited TGTrequest

Visited TGTrequestVisited TGT

Visited TGTVisited TGT

DNS


Charon Authentication:Charon Authentication:Obtaining Session Key with Visited ProxyObtaining Session Key with Visited Proxy


HomeKDC

HomeTGS

VisitedKDC

VisitedTGS

Proxy ticketrequest

Proxy ticketrequestProxy ticket

Proxy ticket

DNS


Handoff from IR to WaveLANHandoff from IR to WaveLAN(load balancing)(load balancing)

Subnet manager

Metering & Credit

Mobility database

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface

IR RF . . .CBQ Agent

deliv. classes

GloMop

GloMopapp

new base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ondmobile host

!



Subnet manager

Metering & Credit

Mobility database

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

new base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ondmobile host

join multicast group;start buffering

classstructure



Subnet manager

Metering & Credit

Mobility database

load balancehint

updatenew base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

mobile host


Extended Handoff SubroutineExtended Handoff Subroutine

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

new base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

mobile host

Home agent

Foreign agentstop buffering;start forwarding

classstructure

Subnet manager

Metering & Credit

Mobility database



unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

new base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

mobile host

Home agent

Foreign agent

new care-of addressack

multicast addr

ack

Subnet manager

Metering & Credit

Mobility database



unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

new base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

mobile host

Home agent

Foreign agent

stopforwarding;

startbuffering

updatestatistics

Subnet manager

Metering & Credit

Mobility database



load balance,handoff prediction

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

old base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

new base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

mobile host

Home agent

Foreign agent

Subnet manager

Metering & Credit

Mobility database


Handoff from WaveLAN to WaveLANHandoff from WaveLAN to WaveLAN(mobility)(mobility)

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

forwarding base station

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

mobile host (strong)

(weak)

buffering base station


DistillerPTM

Dynamic Adaptation via NCMDynamic Adaptation via NCM

HT

TP

mobile proxy

unmodapp

TCP/UDP

Ethernet

TCP/UDP

deliv.classes

controlinterface

IR RF ...cbq

GloMop

GloMopapp

PO

P3

Glo

Mop

Proxy

delivclass co

ntro

lin

terf

.

cont

rol

pane

l

netstate!net

state!

overlay IP overlay IP


DistillerPTM

PTM Load BalancingPTM Load Balancing

HT

TP

mobile proxy

unmodapp

TCP/UDP

Ethernet

TCP/UDP

deliv.classes

controlinterface

IR RF ...cbq

GloMop

GloMopapp

PO

P3

Glo

Mop

Proxy

delivclass co

ntro

lin

terf

.

cont

rol

pane

l

distiller?

spawn

load



DistillerPTM

Delivery class abstractionsDelivery class abstractions

HT

TP

mobile proxy

unmodapp

TCP/UDP

Ethernet

TCP/UDP

deliv.classes

controlinterface

IR RF ...cbq

GloMop

GloMopapp

PO

P3

Glo

Mop

Proxy

delivclass co

ntro

lin

terf

.

cont

rol

pane

l



Dynamic Link AllocationDynamic Link Allocation

. . .RFEthernet

Dynamic Allocation (Class-Based Queuing)

Overlay IP

ControlInterface

NetworkLayer

Data LinkLayer

beac

ond

deca

pd

TCPSnoop


Handoff from WaveLAN to MetricomHandoff from WaveLAN to Metricom(lost beacons)(lost beacons)

new bs (non-cooperating)

!

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

mobile host

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

forwarding base station


DistillerPTM

Flexible Refinement/QoS MechanismFlexible Refinement/QoS Mechanism

HT

TP

mobile proxy

unmodapp

TCP/UDP

Ethernet

TCP/UDP

deliv.classes

controlinterface

IR RF ...cbq

GloMop

GloMopapp

PO

P3

Glo

Mop

Proxy

delivclass co

ntro

lin

terf

.

cont

rol

pane

l

mor

eco

lour

mor

ere

solu

tion

download time: 15 s

QoSpreferences



Handoff from Metricom to WaveLANHandoff from Metricom to WaveLAN(change of domain)(change of domain)

old bs (non-cooperating)

unmodapp

controlpanel

TCP/UDP

Overlay IP

control interface


deliv. classes

GloMop

GloMopapp

mobile host

Overlay IP

controlinterface

snoop

IR RF . . .CBQ

deca

pd

beac

ond

new base station

(new beacon)

periodically retry lower interface

OutlineOutline










Core Daedalus Architecture Summary Core Daedalus Architecture Summary

•• Supports seamless roaming in heterogeneous and Supports seamless roaming in heterogeneous and foreign environmentsforeign environments–– vertical and horizontal handoff supportvertical and horizontal handoff support

•• Custom Network Stack at MHs and (cooperating) BSsCustom Network Stack at MHs and (cooperating) BSs–– unmodified corresponding hosts, home agentsunmodified corresponding hosts, home agents–– compatibility with Mobile-IPcompatibility with Mobile-IP

•• Static assumptions about network characteristicsStatic assumptions about network characteristics

•• Accepts handoff “hints” to handoff controller Accepts handoff “hints” to handoff controller

•• Some protocol-specific network optimizationSome protocol-specific network optimization–– TCP snoopTCP snoop


Extended Daedalus Architecture Summary Extended Daedalus Architecture Summary

•• Adds custom network stack at proxy hostAdds custom network stack at proxy host–– delivery class abstraction for data-type specific transportdelivery class abstraction for data-type specific transport

•• Dynamic allocation at data link (hop by hop)Dynamic allocation at data link (hop by hop)

•• Extensible, independent network services modelExtensible, independent network services model–– mechanisms facilitate localized policy decisionsmechanisms facilitate localized policy decisions

•• Dynamic measurement and notification of changes in Dynamic measurement and notification of changes in network characteristics (via NCM)network characteristics (via NCM)

•• Network performance enhancements Network performance enhancements –– low-latency handofflow-latency handoff–– hierarchical foreign agentshierarchical foreign agents–– additional transport-layer optimizationsadditional transport-layer optimizations


Core Proxy Architecture Summary Core Proxy Architecture Summary

•• Unmodified apps, application-specific protocolsUnmodified apps, application-specific protocols–– proxy mechanism is either transparent to or already proxy mechanism is either transparent to or already

supported by the applicationsupported by the application–– functionality and efficiency limited by the application’s functionality and efficiency limited by the application’s

protocolprotocol

•• On-the-fly distillation and refinement possibleOn-the-fly distillation and refinement possible–– client and network adaptation, unmodified serversclient and network adaptation, unmodified servers–– proxy optimizations (prefetching, caching)proxy optimizations (prefetching, caching)–– dynamic network adaptation is missing (no NCM)dynamic network adaptation is missing (no NCM)

•• Loose coupling with Daedalus stackLoose coupling with Daedalus stack


Extended Proxy Architecture SummaryExtended Proxy Architecture Summary

•• Pluggable proxy architecturePluggable proxy architecture–– support for both modified and unmodified appssupport for both modified and unmodified apps–– separation of load-balancing concerns into PTMseparation of load-balancing concerns into PTM

•• GloMop application support layerGloMop application support layer–– efficient custom protocolefficient custom protocol–– explicit refinement and QoS mechanismsexplicit refinement and QoS mechanisms

•• Authenticated proxied servicesAuthenticated proxied services

•• Tight coupling with Daedalus stackTight coupling with Daedalus stack–– dynamic network adaptation via NCMdynamic network adaptation via NCM–– allow delivery policy through delivery classesallow delivery policy through delivery classes


Some Open IssuesSome Open Issues

•• Elements of the service architectureElements of the service architecture–– complex element interaction and inter-dependencycomplex element interaction and inter-dependency–– the metering mechanism is not fully resolvedthe metering mechanism is not fully resolved

•• Multiple simultaneous network interfacesMultiple simultaneous network interfaces–– multiplexing of application datamultiplexing of application data–– undesirable for power-managementundesirable for power-management

•• Link-layer state on handoffLink-layer state on handoff–– is state transfer necessary?is state transfer necessary?–– how to deliver data queued in base-stationhow to deliver data queued in base-station–– different link-management policy in new network?different link-management policy in new network?

•• Network connection monitorNetwork connection monitor–– stability and granularity of statisticsstability and granularity of statistics


Some Open Issues (continued)Some Open Issues (continued)

•• Function migration Function migration –– “Evil Twin” versus protocol filters at the proxy“Evil Twin” versus protocol filters at the proxy–– can Rover-style migration coexist?can Rover-style migration coexist?

•• Time-constant for proxy-adaptationTime-constant for proxy-adaptation–– how quickly does it adapt, and to what granularity of how quickly does it adapt, and to what granularity of

network variation?network variation?–– should the proxy receive adaptation hints?should the proxy receive adaptation hints?

•• User interface issuesUser interface issues–– understanding and specifying constraintsunderstanding and specifying constraints–– data-type specific refinement controlsdata-type specific refinement controls–– per-chunk, per-document, and per-session constraintsper-chunk, per-document, and per-session constraints

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