wdp by james

8/14/2019 WDP by James

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WDP(WirelessDatagram Protocol)

[email protected]

WAP Logo .


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Reference ModelManagement Entitieshandlesprotocol

initialization,

configuration, and

errorconditionsthat are

nothandled by

theprotocol

itself


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Contents WDP Architecture General Description Example of Implementation in

CDMA SMS


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WDP Architecture(1/2)


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WDP Architecture(2/2) Services offered by WDP : application

addressing by port, optional segmentation and

reassembly and optional error detection Bearer adaptation : maintain the same

service offering at the Transport Service

Access Point Protocol performance over each bearer may

vary. However, the WDP service and primitiveswill remain the same.


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General

Description(1/2) WDP layer operates above the

data capable bearer service Offers a consistent service to the

upper layer protocolThe port number identifies the

higher layer entity above WDP


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General

Description(2/2)


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WDP Management

Entity(1/1) Used as an interface between the WDP layer and the

environment of the device

Provides information to the WDP layer about changes

in the devices environment The mobile is within a coverage area applicable the the

bearer service being invoked

The mobile having sufficient power and the power beingon

Sufficient resources(processing and memory)within themobile are available to WDP

The WDP protocol is correctly configured

The user is willing to receive/transmit data


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Processing Errors When : WDP datagrams are sent from a

WDP provider to another

(e.g. there is no application listening tothe destination port, receiver might nothave enough buffer space to receive alarge message)

WCMP(Wireless Control MessageProtocol) provides an efficient errorhandling mechanism for WDP


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WDP Conformance A minimum set of WDP features that

need to be implemented

Ensure that implementations frommultiple vendors will be able tointeroperate

e.g.) WDP-C-001 : WDP clientfunctions/status=M/requirement : WDPANSI-C-000 or WDP-CDMA-C-000 orWDP-CT-002 or etc


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WDP Adaptation layerSegmentation and Re-

assembly Criteria The application(or higher communication layers)

that are likely to use the bearer service : to estimate

if the typical payload of those applications can behandled by the new bearer service

The bearer service Maximum Transfer Unit(MTU)

- If the application typical payload exceed the bearerMTU, support for SAR SHOULD be included in thenew bearer service specification


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Example of WDP bearer

dependent Profiles(1/2) WDP over CDMA bearer services

E l f WDP


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Example of WDPbearer dependent

Profiles(2/2) WDP over CDMA SMS

SMSMessa

geCenter


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Implement the

WDP(1/9) Following fields are necessary Destination port Source port SAR(Segmentation and

Reassembly)

- bearer dependent way

- underlying bearer


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Implement the

WDP(2/9) Mapping of WDP for IP When IP is used as a routing protocol UDP is adopted as the WDP protocol

definition

e.g.) GSM Circuit Switched Data, GSM GPRS,

ANSI-136 R-Data, CDPD, CDMA-Packet Dataetc.


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Implement the

WDP(3/9) Mapping of WDP to CDMA SMS WDP sends datagrams in the User Data

subparameter of IS-637 SMS point-to-pointmessage

A datagram consists of a four-byte headerfollowed by the data

Datagrams may be too long to fit in one SMSmessage segmented and reassembled at thedestination


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Implement the

WDP(4/9) SMS message containing WDP datagrams

MUST use the WAP teleservice

Datagram structure (sent over IS-637)

SMS User Data

The CHARi fields structure is

Field Length(bits)

SOURCE_PORT 16

DESTINATION-PORT 16

DATA N*8


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Implement the

WDP(5/9)

MSG_TYPE : set 00000000- indicate that thisis a WDP message (distinguishes WDPmessage from other WAP messages)

Field Length(bits)

MSG-TYPE 8

TOTAL-SEGMENTS 8SEGMENT-NUMBER 8

DATAGRAM (NUM_FIELDS-3)*8


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Implement the

WDP(6/9) TOTAL_SEGMENTS : This field shall not be set

to 00000000.

SEGMENT_NUMBER : In the first segment of adatagram this field shall be set to 00000000. DATAGRAM : Fill this field with the datagram

bytes of the segment of the datagram

NUM_FIEDLS field of the User Datasubparameter shall be set to the number ofdatagram bytes in the segment plus 3.


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Implement the

WDP(7/9) Use ofMESSAGE_ID Field IS-637 SMS endpoint has restarted and the first segment

of the first WDP datagram random number in the range

of 0 through 65535. First segment of WDP datagram endpoint MUST

increment the MESSAGE_ID value from the last WDPdatagram sent

Reference number provided via a short message entityinterface protocol

Not first segment of a WDP datagram Equal to theMESSAGE_ID field from the SMS message containing thefirst segment of the WDP datagram


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Implement the

WDP(9/9)


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Port Number Definitions

Example

P ort Number

WAP P ush connectionless session service (client side

A lication/P rotocolPort Number Definitions

WAP P ush secure connectionless session service cli2948

2949

P rotoco : WSP /Data ram

P rotocol : WSP /WTLS/ Data ram

9200WAP connectionless session service1P rotocol : WS P /Data ram

P rotocol : WSP /WTLS/ Data ram2805

P rotocol : WSP /WTP /WTLS/Data ramWAP WTA secure session service

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WAP WTA secure connectionless session service

Total 12 port .

WDP Spec. Appendix B.

wdp by james

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