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Điện thoại di động băng thông rộng không dây P5

Network Architecture value is 500 octets, then IP datagrams of 1500 octets will be segmented into three SNDCP data units. Each one will be transmitted separately and reassembled by the receiving SNDCP layer. A PDP Context essentially represents a virtual connection between an MS and an external PDN. The PDP Context multiplexing is a function that: | Network Architecture 167 value is 500 octets then IP datagrams of 1500 octets will be segmented into three SNDCP data units. Each one will be transmitted separately and reassembled by the receiving SNDCP layer. A PDP Context essentially represents a virtual connection between an MS and an external PDN. The PDP Context multiplexing is a function that routes each data unit received on a particular PDP Context to the appropriate upper layer and routes each data unit arrived from an upper layer to the appropriate PDP Context. For example assume a situation where the MS has set up two PDP Contexts both with type IP but with different IP addresses. One PDP Context could be linked to a remote PDN A and the other could be linked to a remote PDN B. In this case there are two different logical interfaces at the bottom of the IP layer one for each PDP Context. The SNDCP layer is the entity that multiplexes data to and from these two logical interfaces. The Logical Link Control LLC protocol runs also between the MS and the SGSN and it is specified in 3GPP TS 04.64. LLC basically provides data link services as specified in the Open System Interconnection OSI seven-layer model. In particular LLC provides one or more up to 16 separate logical links LLs between the MS and the SGSN which are distinguished into user-LLs used to carry user data and control-LLs used to carry signalling . There can be up to four user-LLs while there are basically three control-LLs one for exchanging GPRS Mobility Management GMM and Session Management SM signalling another to support the Short Message Service SMS and a third to support Location Services LCS see 3GPP TS 03.71 . The user-LLs are established dynamically in the context of the PDP Context Activation procedure 57 and their properties are negotiated between the MS and the SGSN during the establishment phase. Negotiated properties typically include the data transfer mode acknowledged versus unacknowledged the maximum length of transmission .