An Internet Based Communication Server for Remote Control

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(1)(1) Workshop：Computer Systems. (2) Title：An Internet Based Communication Server for Remote Control. (3) Abstract：Today, communication has been applied to everywhere; most devices are equipped with the communication capacity. However, some available older version devices are not provided with the long distance communication functions. This paper introduces a multi-port communication server to solve the problem. This server is able to provide an effective multipoint-to-multipoint communication service. The implementation of such a communication server, based on a low cost with multi-port, is presented. It will describe the driver design of communication server and the interface with the upper-layer access protocols such as PPP, SNMP in Linux. In addition, the server also provided the Web interface and NAT; hence the administrator can manage his/her remote equipments easily via Internet. This paper will describe the detail about the implementation. (4) Author name: Zun-Po Huang, Wen-Shyang Hwang, Jimmin Wang* Current affiliation：Department of Electrical Engineering, National Kaohsiung University of Applied Sciences *Kinghold Technology Co., Ltd. Postal address：415 Chien Kung Road, Kaohsiung, 80782 Taiwan R.O.C. Email address：zunpo_hwang@yahoo.com.tw TEL : 886-7-3814526 EXT.5566 (5) Keyword：Communication Server, Web Interface, PPP, Remote Control. 1.

(2) An Internet Based Communication Server for Remote Control Zun-Po Huang, Wen-Shyang Hwang, and Jimmin Wang* Computer Network Protocol and Applications Laboratory Department of Electrical Engineering, National Kaohsiung University of Applied Sciences *Kinghold Technology Co., Ltd. Email：adrian@wshlab2.ee.kuas.edu.tw remote control today. The most communication. Abstract Today, communication has been applied to. technology of these equipments is the traditional. everywhere; most devices are equipped with the. RS-232. Hence, it’s worth to investigate how to. communication capacity. However, some available. upgrade the communication capacity of these. older version devices are not provided with the long. equipments to communicate through Internet, and. distance communication functions. This paper. how to perform the remote control via Internet.. introduces a multi-port communication server to. Equipments communicate in the Internet have. solve the problem. This server is able to provide an. to obtain IP addresses first, however the version 4. effective multipoint-to-multipoint communication. IP address is insufficient gradually. There are two. service.. a. solutions to solve this problem now. One is IPv6.. communication server, based on a low cost with. Another is NAT (Network Address Translation).. multi-port, is presented. It will describe the driver. Before the version 6 IP address is popular, the NAT. design of communication server and the interface. technique should be the candidate. This paper will. with the upper-layer access protocols such as PPP,. describe the driver implementation of the multi-port. SNMP in Linux. In addition, the server also. communication server implemented by Kinghold. provided the Web interface and NAT; hence the. Technology Co. in 2001. The server is an industry. administrator. remote. computer with multiple RS-232 ports, and prepares. equipments easily via Internet. This paper will. to support the remote control via Web interface, and. describe the detail about the implementation.. an intelligent handling function. The intelligent. Keywords: Communication Server, Web Interface,. handling function is used to monitor data and deal. The. implementation. can. manage. of. such. his/her. with. PPP, Remote Control. events immediately through the default. Knowledge base on database, and then notify administrator to handle it further.. I. Introduction Communication technologies are everywhere now; including wireless (e.g. IEEE 802.11,. II. Communication server hardware. Bluetooth, infrared rays etc.) and wire (e.g. Ethernet,. In this section, we will introduce the hardware of. USB, RS-232, IEEE 488 etc.). The equipments. the communication server; it can be divided to three. without the long distance communication function. main parts: Multi-port card, communication server. are also required to communicate via Internet for. drive card, and communication server host. Figure 1. 2.

(3) shows a Multi-Port card whose main function is. III. System Architecture. used to receive and transmit data from/to remote. The system architecture of the communication. equipments. The connector of Multi-Port card is. server is shown as in Figure 4. A tty driver is. Registered Jack-45 (RJ-45) and it will be converted. developed for the communication server first. At. to RS-232 serial port standard. There is an interface. that time, we use the software named “mgetty” to. that is shown as a red oval drawing in Figure 1, it is. listen to signals from ports of the communication. used to connect with the communication server. server, in order to aware whether any equipments is. drive card as shown in Figure 2. We’ve developed. dialing to the communication server. While the. the driver for this card (Figure 2, ISA slot) whose. dialing tone is arrival, mgetty will response the. main function is used to drive the communication. phone call and then execute the handshake process. server in Linux. Figure 3 shows the communication. between. server host that can provide sixteen equipments to. equipment (DTE). After handshaking, the control. connect with.. authority of mgetty would hand over pppd (PPP. the communication server and the. Daemon). The jobs of pppd are used to transmit or receive PPP packets and configure the options such as MTU/MRU (Max. Transmission/Receive Unit) at both sides. As long as DTE connects to DSE (Data Switching Equipment), administrator can obtain. the. information. about. utilization. of. communication server via Internet immediately. It’s worth to be motioned. In our experience, the. Figure 1. Multi-Port card. communications by using modem and null modem are all tested. There are many situations for DSE directly connecting with DTE by using RS-232 without modem; the technique is named as “Null modem.” Figure 2. Communication server drive card. Figure 4. System architecture Figure 3. Communication server host. 3.

(4) The procedure of DSE operations is shown as. built-in editor for the binary, hexadecimal and. in Figure 5. The frames from the remote equipment. disassembler modes. The transmitted or received. will be received by the multi-port card driver, and. PPP frames at both sides are monitored by BIEW as. inserted into the corresponding received queue. The. shown in Figure 6. In the figure, a red shape (0x7e,. tty driver would remove frames from the received. 0xff… 0xc6 0x7e) is marked to present the DSE is. queues, and then passes the frames to the PPP. transmitting a PPP frame that is an IPCP (Internet. module. The PPP module inspects these frames to. Protocol Control Protocol) to the remote DTE. By. subdivide into two kind format frames. One is the. using BIEW, we can accurately verify the. PPP control frame that is used to configure the. communication between DSE and DTE and the tty. options such as MTU, MRU at both sides. While. driver for communication server whether successful. the PPP module receives the PPP control frame, it. to work.. will pass these frames to pppd (at user mode) in order to negotiate with the parameters that both sides would like to configure. The other frame format is the data packet in the network layer such as IPv4, IPv6, and IPX. When the PPP module receives these network layer packets, it would pass them to the corresponding process on Linux kernel.. Figure 6. Viewing data buffer on communication. Finally, the NAT mechanism would update their. server. packet headers, and transmit them to Internet. In this implementation, the PPP frame is the major data format. The PPP frame format [7] is shown as in Figure 7. The figure does not include the start and stop bits of asynchronous links, nor any bits or octets inserted for transparency. The fields are transmitted from left to right. The Flag field is a single octet and indicates the beginning or end of a frame (named frame separator). The Flag field consists of the hexadecimal code 0x7e. There is only one Flag is required between two frames. The Address field is a single octet and contains the. Figure 5. DSE Operations. hexadecimal code 0xff, it is an All-Stations address. PPP does not assign any individual station address.. IV. Implementation results While DTE connecting to DSE, we use the. The All-Stations address means this frame will. software named BIEW (Binary vIEW) [10] to view. always be received. The Control field is a single. the binary file (/proc/kcore) on communication. octet and contains the hexadecimal code 0x03.. server for finding out what data buffer temporarily. The Protocol field is two octets long, and its. at that time. BIEW is an advanced file viewer with. value identifies the protocol that encapsulated in the. 4.

(5) Information field of the frame. For example, the. page is as shown in Figure 12. It presents a. protocol field that contains the hexadecimal code. traffic analysis on a specify day that the. 0x8021 is to indicate an IPCP encapsulated in the. administrator could choose over his own will.. Information field of the frame. It could find them in. As this example, we choose the traffic analysis. Figure 6 about the sixth and seventh character from. chart on June 13, 2002.. the place we marked with the red curve. There is a. 3. The “On-Line equipments” function is use to. little difference of the PPP frames between in. know how many equipments are connected to. Figure 6 and in Figure 7, because of the procedure. the communication server now.. Octet-stuffed [8].. 4. The “I.D. for specific equipments” function presents that equipment must get a user name and a password if it would make a phone call to communication server by using Dial-up. 5. The “Add an I.D. for specific equipments”. Figure 7. PPP frame format. function presents the administrator would add Since the hardware is a novel design, the. an I.D. for a specific equipment.. original serial port device will work abnormally. A new device for the communication server is written, the figure 6 shows all communications are successful. In addition, we built a Web Server Administration System shown as in Figure 8 to get the information which administrator would like to care. about.. In. Figure. 8,. we. could. click. “Administrator Login” to login “Administration Menu” as shown in Figure 9. There are five options. Figure 8. Web Server Administration System. can be chosen. These options are follows: 1. The “SerialPort options” presents that the administrator would like to configure options such as MTU, MRU etc. for serial ports as shown in Figure 10. It shows the administrator could configure the existence serial port (rs1 or ttyS1 in Figure 10) or create a new serial port if needed.. Figure 9. Administration Menu. 2. The “Traffic Analysis” presents that the administrator could get how much traffic on the communication server now. After clicking the “Traffic Analysis” option, the sub-menu page is as shown in Figure 11. While the “Total Traffic Analysis” option is chosen, the statistic traffic. Figure 10. Configure Serial Port Menu. 5.

(6) REFERENCE [1] Marino, P.; Poza, F.; Nogueira, J. “Industrial LAN’s with real-time communication servers”, IEEE International Workshop, pp.119-127, 1997 [2] Jing Bai, Bingyi Hu, Yonghong Zhang, and. Figure 11. Traffic Analysis Menu. Datian Ye, “A Communication Server for Telemedicine. Applications”,. Technology. in. Information. Biomedicine,. IEEE. Transactions, Volume: 1 Issue: 3, pp. 205-209, Sept. 1997 [3] Geoffrey C. Sauerborn, “The distributed interactive. simulation. (DIS). lethality. communication server”, Distributed Interactive Simulation. Figure 12. Graph for Traffic Analysis. and. Real-Time. Applications,. pp.82-85, 1998 [4] Alessandro Rubini & Jonathan Corbet, “Linux. V. Conclus ion and future work In this paper, we propose a communication. Device Drivers, 2nd Edition”, O’REILLY, June. server with multi-ports to connect multiple remote. 2001. [5] Rémy Card and Frank Mével, “the LINUX KERNEL book”, WILEY, 1998. [6] Richard Stones and Neil Matthew, “Beginning Linux Programming”, WROX, October 1999. [7] W. Simpson, “The Point-to-Point Protocol (PPP) for the Transmission of Mult i-Protocol Datagrams over the Point-to-Point Link”, RFC 1331, May 1992. [8] W. Simpson, “PPP in HDLC-like Framing”, RFC 1662, July 1994. [9] William Stallings, “Operating Systems, Fourth Edition”, Prentice Hall, 2001 [10] http://biew.sourceforge.net/, BIEW software.. equipments simultaneously. A novel tty driver is written in Linux. This driver supports not only each port communication between DSE and DTE but also redirects data from PPP to Ethernet. Therefore, the administrator could configure the relative options for equipments and obtain the information about the utilization of communication sever immediately through the web server that have been built by using PHP and MySQL. In the future, more SNMP (Simple Network Management. Protocol). functions ,. is. an. Internet-standard protocol for managing each node on an IP network, will be implemented in the communication server to realize an “intelligent” communication server.. 6.

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