vertical qos mapping over wireless interfaces
Post on 12-Jan-2016
32 Views
Preview:
DESCRIPTION
TRANSCRIPT
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 ChenDepartment of Communications Engineering CCU
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
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
CN Group
Introduction(cont.)
Qos achieved at each layer of the network Define an interface between adjacent layers
4
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
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
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
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
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
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
10Reference :M. Marchese, QoS over Heterogeneous Networks, John Wiley & Sons, 2007.
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 RTD 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
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
RTD(tk) allocation the instant tk
An information vector TD buffer Simply the error e(tk)
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 [tk-1 , tk] 12
CN Group
Reference scheme for dynamic QoS mapping over TI-SAP interface(cont.)
RTF(tk) = RTD(tk–1) + wk e(t⋅ k) wk 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 : Wk dynamically over time 13
CN Group
Example results Trunk of 50 VoIP TI -> TI-SAP -> TD
ATM at TD layer
Only one IP queueand 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
change14 Quick reaction and bandwidth adaptation
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
CN Group
Thank you
16
CN Group
BSM architectureBroadband 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
CN Group
ETSI BSM protocol stack
18Reference : ETSI, Satellite Earth Stations and Systems (SES), Broadband Satellite Multimedia, IP over Satellite, ETSI Technical Report, TR 101 985 V1.1.2, November 2002.
top related