48 protocols. </p> <p>Communication between the data and control threads, and |
48 protocols. </p> <p>Communication between the data and control threads, and |
49 between the layers is performed by an asynchronous messaging system known |
49 between the layers is performed by an asynchronous messaging system known |
50 as the <i>Transport</i>. </p> <fig id="GUID-5467DE40-01FB-5D50-BB6D-866D5C425ADA"> |
50 as the <i>Transport</i>. </p> <fig id="GUID-5467DE40-01FB-5D50-BB6D-866D5C425ADA"> |
51 <title> Separation of Data Flows and Control in the Comms Architecture |
51 <title> Separation of Data Flows and Control in the Comms Architecture |
52 </title> |
52 </title> |
53 <image href="GUID-69847989-624F-5119-8AC0-3D95D72AF076_d0e82800_href.png" placement="inline"/> |
53 <image href="GUID-69847989-624F-5119-8AC0-3D95D72AF076_d0e76088_href.png" placement="inline"/> |
54 </fig> <p>In fact the Comms Architecture actually divides the area marked |
54 </fig> <p>In fact the Comms Architecture actually divides the area marked |
55 Control above into two areas, <i>Control</i> and <i>Management</i>. This is |
55 Control above into two areas, <i>Control</i> and <i>Management</i>. This is |
56 the reason that this Comms Architecture is also known as the <i>Three-Plane |
56 the reason that this Comms Architecture is also known as the <i>Three-Plane |
57 Architecture</i>. In future diagrams there will be three <i>Planes</i>: Data |
57 Architecture</i>. In future diagrams there will be three <i>Planes</i>: Data |
58 Flow, Control, and Management. The Control Plane is often shown divided in |
58 Flow, Control, and Management. The Control Plane is often shown divided in |
75 to another at any level in the stack providing full mobility. </p> <fig id="GUID-BE9C7C7A-DD4C-5199-81C1-E8856BA48AD6"> |
75 to another at any level in the stack providing full mobility. </p> <fig id="GUID-BE9C7C7A-DD4C-5199-81C1-E8856BA48AD6"> |
76 <title> Example of several potential stacks of protocols reusing |
76 <title> Example of several potential stacks of protocols reusing |
77 the same protocols. </title> |
77 the same protocols. </title> |
78 <desc><p>In this example IP and TCP are used in three different stacks. A |
78 <desc><p>In this example IP and TCP are used in three different stacks. A |
79 combination of these Stacks could be running concurrently. </p> </desc> |
79 combination of these Stacks could be running concurrently. </p> </desc> |
80 <image href="GUID-FBBC7F0D-FD4B-58B7-BEAC-B68EEBD19ACF_d0e82848_href.png" placement="inline"/> |
80 <image href="GUID-FBBC7F0D-FD4B-58B7-BEAC-B68EEBD19ACF_d0e76136_href.png" placement="inline"/> |
81 </fig> <p>Each stack requires a configuration that details how these protocols |
81 </fig> <p>Each stack requires a configuration that details how these protocols |
82 find and work with each other; the protocols themselves need to know how to |
82 find and work with each other; the protocols themselves need to know how to |
83 talk with the other protocols. To allow flexibility, each protocol must avoid |
83 talk with the other protocols. To allow flexibility, each protocol must avoid |
84 making assumptions about the protocols below or above it, and instead rely |
84 making assumptions about the protocols below or above it, and instead rely |
85 on the framework and device configuration. The framework ensures that each |
85 on the framework and device configuration. The framework ensures that each |
95 of the Comms Architecture in Symbian platform from the point of view of an |
95 of the Comms Architecture in Symbian platform from the point of view of an |
96 end-to-end connection. </p> <fig id="GUID-8DFF2EAE-21F7-5119-88E7-19BF2076A76F"> |
96 end-to-end connection. </p> <fig id="GUID-8DFF2EAE-21F7-5119-88E7-19BF2076A76F"> |
97 <title> The Comms Architecture shown in the scope of a complete |
97 <title> The Comms Architecture shown in the scope of a complete |
98 protocol stack and the end-to-end path between the applications |
98 protocol stack and the end-to-end path between the applications |
99 on each device. </title> |
99 on each device. </title> |
100 <image href="GUID-26399981-1E45-5578-851E-D234295F3B05_d0e82865_href.png" placement="inline"/> |
100 <image href="GUID-26399981-1E45-5578-851E-D234295F3B05_d0e76153_href.png" placement="inline"/> |
101 </fig> </section> |
101 </fig> </section> |
102 <section id="GUID-1BAC904D-F705-5416-A0F6-3D5FA3B10A7E"><title>Performance</title> <p>A |
102 <section id="GUID-1BAC904D-F705-5416-A0F6-3D5FA3B10A7E"><title>Performance</title> <p>A |
103 key requirement of the Comms Architecture is the performance of data transfer. |
103 key requirement of the Comms Architecture is the performance of data transfer. |
104 The data transfer performance can be measured in three different ways: </p> <ul> |
104 The data transfer performance can be measured in three different ways: </p> <ul> |
105 <li id="GUID-02E93F2D-E249-516C-98B2-AFB9A22CCEF4"><p> <b>Throughput</b> - |
105 <li id="GUID-02E93F2D-E249-516C-98B2-AFB9A22CCEF4"><p> <b>Throughput</b> - |