Networking Blog

Posts Tagged ‘networking’

ACROSSER Technology announces the release of the AR-R5700 Series of Networking Security Appliances based upon the Intel Q35 Chipset. It is a system capable of utilizing the Core 2 Quad, Core 2 Duo and Celeron Intel embedded processors. It is the latest member of ACROSSER’s Networking 1U 19″ Rack Mount System family. These Networking systems are designed for applications where reliability and performance are critical for the applications.

For large enterprise and other applications requiring a large demand for data transfer, High performance Networking appliances are the best choice in this situation. The AR-R5700 series has many desirable design features. The most powerful feature is the Intel Q35 and ICH9R Chipset which can support Intel CPU’s up to the Core2Quad level. This is a new generation supporting CPU FSB at 1333MHz. The wide range CPU support can give you the flexibility to choose the best one for your application. Memory capacity of up to 8GB using 4 DDR2 DIMM sockets also provides for very high level performance.

The AR-R5700 Series uses a modular design to achieve additional Networking ports using the AR-B2003 and AR-B2004. The AR-B2003 adds four Gigabit Ethernet RJ-45 LAN ports. For long distance data transfer, Fiber Gigabit Ports can provide the capabilities you need. The AR-B2004 expansion module can fulfill the requirement; it can support not only 2 more SPF Gigabit Ethernet but also 2 more RJ-45 Gigabit Ethernet. These 2 modules are connected through a PCIE x 8 channel from Intel Q35 on the AR-B5700.

By pass functionality is also a critical feature for 24 hour operation networking devices. It can also be implemented in this series of models. There is one pair of by pass LAN on the basic AR-B5700 model. However, there is one more pair on the AR-B2003 and AR-B2004 expansion modules.

There are 3 models in AR-R5700 series:

1. AR-R5700: Intel Q35 +ICH9R with 6 x RJ45 Gigabit Ethernet;
2. AR-R5700L8F2: Intel Q35 +ICH9R with 8 x RJ45 Gigabit Ethernet and 2 SPF Gigabit Ethernet;
3. AR-R5700L10: Intel Q35 +ICH9R with 10 x RJ45 Gigabit Ethernet.

AR-R5700 series features:

• Intel Q35+ICH9R chipset supports CPU from Core2Quad/Core2Duo/Celeron, front side bus up to 1333MHz.
• 4 x Memory slots in total, supports maximum up to 8GB using 64bit OS.
• 6 x RJ-45 Gigabit Ethernet standard, maximum up to 10 RJ-45 Gigabit Ethernet.
• Flexible Extension Gigabit Ethernet module (2 x RJ-45 + 2 x SPF Gigabit Ethernet) or 4 x RJ-45 Gigabit Ethernet.
• Console re-direction by serial port (RJ-45 connector with a DB9 cable).
• By pass function controlled by H/W and Software.
• 16 x 2 characters LCD module.

The Transmission Control Protocol (TCP) provides fairly reliable transfers and it attempts to deliver the packets in order at their destination. This makes it very suitable for any application which would like to transfer a sequence of bytes (e.g., a file transfer, an e-mail or the Web) to its destination in a somewhat reliable and sequential fashion. TCP is the most ubiquitous protocol on today’s Internet and is used by many of the Internet applications that we use on an everyday basis. The Web is built on TCP/IP as HTTP uses TCP to manage the individual conversations between Web clients and Web servers by dividing the HTTP messages into smaller pieces and delivering them in order at the destination.

TCP employs the use of a number of events and controls to implement its behaviour and it is therefore far more complicated an implementation than UDP. Briefly, TCP therefore includes the following features:

1. Connection Oriented: When a TCP connection is created, the underlying protocol implemented a handshake mechanism in order to establish a TCP connection. TCP connections therefore have state and have a lifetime until they are disconnected. The procedure is broadly as follows. A client sends a SYN packet to the desired location, the TCP server, which is a minimal 40-byte packet which contains the sender’s and destination addresses. When the server receives this packet it will respond with an ACK packet, which is an acknowledgement of the server’s willingness to accept the connection.

2. Multiple TCP Connections: The connection request at the server is implemented using an accept() method. A TCP server can block an accept call or use an asynchronous event to indicate that the server should accept the connection. Once accepted, the server typically spawns a new thread and creates a socket to manage this new connection. A server therefore generally acts as a listener and multi-plexor for managing multiple TCP connections and brokers these requests to actual TCP sockets that create a one-to-one TCP relationship with the client.

3. Data Control Mechanisms: attempt to deliver data in a reliable in-order fashion and therefore employ the use of ACKs to acknowledge delivery of packets as and when they arrive. The TCP receiver also implements a buffer that is used to slot the packets in the correct order before data is delivered to the application. Therefore, even though data might arrive in the incorrect order in the first instance, the packets are re-ordered before being passed to the application.

4. TCP Events: Most C++ TCP implementations allow an application to attach itself as a listener to a socket.4 Since sockets can be senders and/or receivers of information, clients and servers receive events based on their role in the TCP connection. A client TCP socket (or the socket that is brokered to deal with the incoming connection at the server) therefore can receive Connect, Send, Receive and Disconnected events. Briefly, a client is notifed of a Connect event, when it receives an ACK back from the server indicating that the server has accepted the connection request. A Send event is passed to the client when the data has been sent to the server (either using edge- or level-trigger mechanisms) and after a connect event has been received. A Receive event is received by the client when data has arrived and is ready for collection (for asynchronous notifcation) and a Disconnected event means that the connection has been terminated. A server in the TCP implementation generally acts as a broker to create new sockets for dealing with new connections and therefore it is typically only interested in receiving Accept and Receive events. When a client has requested a connection (by sending a SYN packet), the server passes an Accept event to the listener for server connections. The application can use this event in order to call the accept() socket method in order to accept this connection (however, in Java this behaviour is implemented through a blocking call to the ServerSocket accept method). Thereafter, a server socket can be notifed with a Receive event when data has arrived and is ready for collection.