09-07-2012, 10:12 AM
BROADBAND CONVERGENCE NETWORKING
BROADBAND CONVERGENCE.doc (Size: 385.5 KB / Downloads: 39)
INTRODUCTION
PROBLEM DEFINITION
The successful deployment of broadband networks and services requires a comprehensive assessment of the capabilities of the impacted network elements. In particular, conformance, performance, and interoperability testing of switching systems and routers is necessary for all aspects of network and service deployment. To ensure timely, high quality deployment of products and services on Multi Protocol Label Switching , Asynchronous Transfer Mode (ATM), Frame Relay, and/or Internet Protocol (IP)-based networks, network service providers need to select network equipment with proven reliability and the interoperability necessary to support the services they plan to offer. Often, service providers will refuse to purchase new products and capabilities from their existing telecommunications suppliers if they have experienced numerous or significant field problems with that supplier’s products in the past.
DATA FLOW DIAGRAM
The Data flow oriented design has been adopted for the system. The main attraction of the data flow oriented design is that it is amenable to a wide range of application areas. Data flow Diagram show’s the logical flow of the system and define boundaries of the system. It describes the Input (source), output (destination), Database (Data Sources), and Procedures (Data flows) all in a format that meets the user’s requirements. While preparing that logical system design, it is tried to specify the user needs at a level of detail that virtually determines the information flow into and out of the system, the required data sources and the specified objects of the design were also considered.
THE ATM/IP NET
The switch in the A/I net. Each input and output port processor contains two parts, one for ATM and one for IP. In implementation, the input and output port processors are collocated and fabricated on a single chip. The switch contains two central controllers. One handles ATM call processing; the other executes IP routing protocols (e.g., BGP, OSPF) and the IP management and control protocols (e.g., SNMP, ICMP). Processing regular ATM cells or IP packets is done by the input/output port processors. In the A/I Net, ATM is for real-time traffic, IP for non-real-time traffic. An IP packet is first encapsulated in ATM adaptation layer type 5 (AAL5) and then divided into cells. The cells which carry IP traffic are called IP cells in our discussion below. A default VC throughout the entire network is used to carry IP cells. Real-time ATM cells are assigned a higher priority than IP cells. Non-real-time ATM cells have the same priority as IP cells.
ANALYSIS OF IMPLEMENTATION
In the A/I Net ATM and IP cells are mixed on a link. But cells from different IP packets are not interleaved-consecutive IP cells belong to the same IP packet. Noninterleaving transmission of IP packets is the key feature of the A/I Net (A later section describe its implementation). IP packets in other ATM/IP integrated networks are carried by different ATM VCs and their transmission are interleaved. Cell discarding during congestion will lead to the loss of many IP packets. To make the matter worse, transmitting the remaining cells of a packet that already experiences cell dropping accomplishes nothing but bandwidth waste. To reduce the loss, early discarding and packet-based discarding have been proposed.
BROADBAND CONVERGENCE.doc (Size: 385.5 KB / Downloads: 39)
INTRODUCTION
PROBLEM DEFINITION
The successful deployment of broadband networks and services requires a comprehensive assessment of the capabilities of the impacted network elements. In particular, conformance, performance, and interoperability testing of switching systems and routers is necessary for all aspects of network and service deployment. To ensure timely, high quality deployment of products and services on Multi Protocol Label Switching , Asynchronous Transfer Mode (ATM), Frame Relay, and/or Internet Protocol (IP)-based networks, network service providers need to select network equipment with proven reliability and the interoperability necessary to support the services they plan to offer. Often, service providers will refuse to purchase new products and capabilities from their existing telecommunications suppliers if they have experienced numerous or significant field problems with that supplier’s products in the past.
DATA FLOW DIAGRAM
The Data flow oriented design has been adopted for the system. The main attraction of the data flow oriented design is that it is amenable to a wide range of application areas. Data flow Diagram show’s the logical flow of the system and define boundaries of the system. It describes the Input (source), output (destination), Database (Data Sources), and Procedures (Data flows) all in a format that meets the user’s requirements. While preparing that logical system design, it is tried to specify the user needs at a level of detail that virtually determines the information flow into and out of the system, the required data sources and the specified objects of the design were also considered.
THE ATM/IP NET
The switch in the A/I net. Each input and output port processor contains two parts, one for ATM and one for IP. In implementation, the input and output port processors are collocated and fabricated on a single chip. The switch contains two central controllers. One handles ATM call processing; the other executes IP routing protocols (e.g., BGP, OSPF) and the IP management and control protocols (e.g., SNMP, ICMP). Processing regular ATM cells or IP packets is done by the input/output port processors. In the A/I Net, ATM is for real-time traffic, IP for non-real-time traffic. An IP packet is first encapsulated in ATM adaptation layer type 5 (AAL5) and then divided into cells. The cells which carry IP traffic are called IP cells in our discussion below. A default VC throughout the entire network is used to carry IP cells. Real-time ATM cells are assigned a higher priority than IP cells. Non-real-time ATM cells have the same priority as IP cells.
ANALYSIS OF IMPLEMENTATION
In the A/I Net ATM and IP cells are mixed on a link. But cells from different IP packets are not interleaved-consecutive IP cells belong to the same IP packet. Noninterleaving transmission of IP packets is the key feature of the A/I Net (A later section describe its implementation). IP packets in other ATM/IP integrated networks are carried by different ATM VCs and their transmission are interleaved. Cell discarding during congestion will lead to the loss of many IP packets. To make the matter worse, transmitting the remaining cells of a packet that already experiences cell dropping accomplishes nothing but bandwidth waste. To reduce the loss, early discarding and packet-based discarding have been proposed.