università campus bio-medico di roma facoltà di ingegneria ingegneria biomedica wide-scale,...

Università Campus Bio-Medico di RomaFacoltà Di Ingegneria — Ingegneria Biomedica

Wide-scalE, Broadband, MIddleware for Network

Distributed Services

Guaranteed services in heterogeneous wireless

access networks

Giulio IannelloUniversità Campus Bio-Medico di Roma




Who we are

• Università Campus Bio-Medico di Roma: young institution borne in 1993 around a Faculty of Medicine

• In 1999 started a Faculty of Engineering with a course in Biomedical Engineering

• Tight integration between the two Faculties• Fields of interest: informatics, system modeling,

biomaterials, biomedical instruments, robotics




Who we are

• Research group on Computer Networks and Advanced Distributed Applications– COFIN project: Scalability and Quality of Service in Web

Systems (closed)– FIRB project: Wide-scalE, Broadband, MIddleware for

Network Distributed Services (active) – Hospital Information System for Students (HISS) project

funded by Hewlett-Packard (active)




Who we are

• Contributors:– Filippo Cacace– Maria Cinque– Michele Crudele– Stefano Za– Massimo Bernaschi (CNR IAC)– Pierluigi Salvo Rossi (Napoli Federico II, DIS)– Luca Vollero (Napoli Federico II, DIS)




Motivations

• Making Internet services accessible anywhere, anytime, anyhow, and by anyone is a research field that emerged recently

• W3C Device Independence (DI) Activity focuses on making Web accessible anytime and anyhow– many access mechanisms (including mobile devices)– many modes of use (including multimedia ones)




Motivations

• DI can be considered from three perspectives:– user– authoring techniques– delivery mechanisms

• Our activity focuses mainly on the third item and concerns system support to service guarantees in the Device Independence vision




Motivations

Delivery mechanisms perspective




Motivations

• The delivery subsystem should be able to reserve resources needed to deliver services in a highly dynamic environment

• Our activity on these “traditional” Quality of Service issues is currently focused on: – heterogeneous wireless access networks – dynamic changes in network configuration and workload




Motivations

• Service adaptation: a complementary concept to provide effective support to universal access:

• Adaptation to access media– bandwidth, reliability, security

• Adaptation to the interface (terminal device)– screen, power consumption, computing power

• Adaptation to the context– localization, time, other circumstances, preferences




QoS support in 802.11

• Supporting traffic differentiation in 802.11 WLAN (infrastructured configurations)– layer 3 management for downstream traffic– for upstream traffic we have proposed a minor

modification to MAC protocol at the base station (called Frame Dropping)

– can be implemented at firmware level, no change required to mobile stations





if ACKs are dropped, the MS perceives channel congestion

MS increase its CW and this induces

traffic differentiation





Channel utilization (saturation)





Comparison with DFS (CBR flows) Overall channel utilization (CBR flows)





• Forthcoming standard 802.11e – advanced protocol with enhanced scheduling

mechanisms at MAC layer– performance modeling of throughput and delay in

saturation and non saturation conditions (Luca Vollero visiting Albert Banchs/Madrid—Carlos III)

– medium term goal: strategies for on-line configuration of MAC parameters




Mobility and seamless connectivity

• Integration of WLANs and 2.5G/3G cellular networks

• Loosely-coupled approach: Mobile IPv6• Focus on multi-homed mobile hosts: vertical handoff

– seamless and efficient handoffs– handoff policies– cooperative multi-homed connectivity





• IPv6 Mobility Testbed

• Operative at Campus Bio-Medico





• Vertical handoff performance improvement • Performance analysis of transport protocols during

handoffs– TCP– UDP/RTP

• Intelligent handoffs through rule-based management– merging of preferences and other context information





handoff vs. offered workloadforced handoff (WLAN 3G)




Adaptive streaming

• CC/PP capable clients and web servers– Intel CC/PP framework, Java-based adaptation modules– Profile Resolution Engine (DICO—UNIMI)– on-line assessment of network performance

• Transcoding modules– algorithms for trading-off reproduction quality and bitrate– real-time multimedia processing (RT-MMP) toolkit

• Adaptive RTP server




Adaptive streaming

Intel CC/PP framework




Adaptive streaming

Web ServerWeb Server

Video Video ServerServer

+ + degradatordegradator

ClientClient

Profile’s Profile’s repositoryrepository

Adapter Adapter engine engine

(servlet)(servlet)

HTTP Request + HTTP Request + CC/PPCC/PP

ProbingProbing

1. Client Profile 1. Client Profile learninglearning

2. Environment learning2. Environment learningRTPRTP

3. Info 3. Info mergingmerging

1.1. The device requests a web page via The device requests a web page via HTTPHTTP

Using CC/PP, it sends also its infosUsing CC/PP, it sends also its infos

HTTP ResponseHTTP Response

ProfileProfile

2.2. The web server (CC/PP aware) supplies The web server (CC/PP aware) supplies to load device’s profile into a DBto load device’s profile into a DB

3.3. The server replies to the client with an The server replies to the client with an adapted web page in which there is adapted web page in which there is movies’ list movies’ list

4.4. After client’s choice, the server calls After client’s choice, the server calls the Adapter Enginethe Adapter Engine

5.5. This servlet retrives client’s info, from This servlet retrives client’s info, from repository, to know its constrainsrepository, to know its constrains6.6. The servlet now has to contact the The servlet now has to contact the

“right” Video Server, supplying to it “right” Video Server, supplying to it client’s IDclient’s ID

7.7. The Video Server sendes “probe traffic” The Video Server sendes “probe traffic” to the client to know the network’s to the client to know the network’s statusstatus

8.8. This infos are sent to the AdapterThis infos are sent to the Adapter9.9. Now the Adapter Engine determines the Now the Adapter Engine determines the bottelneck and how to adapt the video bottelneck and how to adapt the video (degradator factor)(degradator factor)

10.10. A connection via RTP is estabilished for A connection via RTP is estabilished for the streaming videothe streaming video




End

Thank you

Questions?

università campus bio-medico di roma facoltà di ingegneria ingegneria biomedica wide-scale,...

Documents

roma slide

network configuration

workload slide

robotics slide

internet services accessible

hewlettpackard active

multimedia ones slide

access mechanisms