1. CN Group VERTICAL QOS MAPPING OVER WIRELESS INTERFACES Marchese, M.; Mongelli, M.; Wireless Communications, IEEE Volume 16, Issue 2, April 2009 Page(s):37 - 43 Report : Jai- Shiarng Chen Department of Communications Engineering CCU

2. CN Group Outline Introduction The technology-independent service access point TI-SAP model Vertical QoS mapping problem Reference scheme for dynamic QoS mapping over TI-SAP interface Example results conclusions 2

3. CN Group Introduction Modern telecommunication networks  Different portions and technologies The end-to-end Qos is challenged  Over heterogeneous  Horizontal QoS Source to the destination The protocol used and the network features  Vertical QoS Composed of layered architectures 3

4. CN Group Introduction(cont.) Qos achieved at each layer of the network Define an interface between adjacent layers 4

5. CN Group Introduction(cont.) Establish a QoS-oriented between layers A good example  European Telecommunications Standards Institute (ETSI)  Broadband satellite multimedia(BSM)  Satellite-dependent(SD) Physical, MAC and link control  Satellite-independent(SI) IP and upper layers  Satellite independent –service access point(SI_SAP) Offer QoS service The architecture is generalized  Different physical supports  Wire and wireless 5

6. CN Group Introduction(cont.) The idea is to extend  Technology-dependent(TD)  Technology-independent(TI)  Technology independent-service access point(TI-SAP) Use specific hardware/software solution, often covered by patents TD and TI communication without affecting TD-layer implementation Dynamic bandwidth adaptation at TI-SAP  Vertical QoS mapping 6

7. CN Group The technology-independent service access point TI-SAP within a wireless portion  Overall IP-based heterogeneous network composed of wide area networks Wireless portion is located in the middle  Between two generic WANs The lower must offer a QoS  Guarantee to the upper layer 7

8. CN Group TI-SAP model TI-SAP include  Abstract queue  Identifies a specific QoS level  Transfer packets from the TI to the TD layer A battery of buffers at the TI-SAP  Any network node is implemented  Different levels of QoS Different QoS service  TI layer can access and modify the abstract queue 8

9. CN Group TI-SAP model TI resource management entry  Allocates and manage resource (IP) TD resource management entry  Physically allocates the required resource  Network control center(NCC) Bandwidth is allocated –Different remote stations QoS mapping management entry  Receive resource require from TI  The entry maps it on the lower layer  Applied at the TD layer Translate the request(reservation, release and modification actions) 9

10. CN Group Vertical QoS mapping problem Change of information unit  The information come from upper layer  Overhead TI layer is encapsulated within new frame composed information TD layer must consider the additional bits of the header Heterogeneous traffic aggregation  Bandwidth must be adapted at TD Queue number decreases from upper to lower layer Fading effect  Must handle time-vary-channel condition Such as satellite and wireless links 10 Reference :M. Marchese, QoS over Heterogeneous Networks, John Wiley & Sons, 2007.

11. CN Group Vertical QoS mapping problem (cont.) Joint problem  Fading effect can be modeled A multiplicative stochastic process 0(total outage)to 1(free error channel) The model can be iterated  Bandwidth adaptation Very challenging R TD guarantee to TI layer queue Equivalent bandwidth(EqB) –Minimum service rate to guarantee a certain degree of QoS –Single QoS constraint The complexity of overall input flow process –Almost non-applicable 11

12. CN Group Reference scheme for dynamic QoS mapping over TI-SAP interface Allocate bandwidth periodically at the TD layer  After receiving the QoS constraints through TI-SAP R TD (t k ) allocation the instant t k An information vector  TD buffer  Simply the error e(t k ) Above 0, minimum additional amount of bandwidth –Enable the satisfaction of QoS constraints Below 0, over-provisioned bandwidth –Maximum amount of bandwidth that can dropped without violating QoS  Minimum bandwidth that guarantees the QoS constraints In the interval [t k-1, t k ] 12

13. CN Group Reference scheme for dynamic QoS mapping over TI-SAP interface(cont.) R TF (t k ) = R TD (t k–1 ) + w k ⋅ e(t k )  w k is a weight Arrived and lost bits at the TD-layer  Compute the loss rate that can be tolerated  Check the bandwidth under-provision or over-provision Estimation of the bandwidth requirement  Allocate the bandwidth in the next interval consequently Reference chaser bandwidth controller(RCBC)  Use the sensitivity of the system performance Variations of the allocation bandwidth Weight : W k dynamically over time 13

14. CN Group Example results Trunk of 50 VoIP TI -> TI-SAP -> TD  ATM at TD layer Only one IP queue and one ATM queue Performance metric  Packet loss 2 。 10 -2  Packet delay 20 ms Bandwidth reallocation  Every minute Buffer size  TI : 1600bytes (20 VoIP packet)  TD: 3710 byte (70 ATM cell) Four peaks  Reduction factor change 14 Quick reaction and bandwidth adaptation

15. CN Group Conclusion Dynamic schemes based on measure  Quickly to change in traffic  Performance parameter Complex mathematical traffic models  Unsuitable for real network conditions Future research  Implementation detail of bandwidth adaptation mechanisms  Implement RCBC within a TI-SAP-based architecture 15

16. CN Group Thank you 16

17. CN Group BSM architecture Broadband satellite multimedia CSF-1: The interface between the IETF protocols and the Client function (internal to the IP layer). CSF-2: The interface between the peer IETF Client [interworking] functions. CSF-3: The interface between the Client function and the Server function(s). 17

18. CN Group ETSI BSM protocol stack 18 Reference : ETSI, Satellite Earth Stations and Systems (SES), Broadband Satellite Multimedia, IP over Satellite, ETSI Technical Report, TR 101 985 V1.1.2, November 2002.