IP Users Manual Revision A6 Friday, January 26, 2001
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Table Of Contents Getting Started.....................................................................................................................4 Initialization ..................................................................................................................... 4 EZCom-IP Explorer Introduction ................................................................................. 4 Point-to-Point Link Example ...............................
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 List Of Tables & Figures Table 1, Factory Default Settings ....................................................................................... 4 Table 2, Point-To-Point Setup Parameters ........................................................................ 6 Table 3, Example II, EZCom-IP Radio Settings ............................................................... 14 Table 4, Example II Device IP Addresses ............................................
Grayhill EZCom IP Users Manual Section 1. Rev A6 1/26/2001 Getting Started Initialization When you first remove an EZCom IP radio from it’s carton and apply power to it, the radio will boot-up and go through a series of self-tests. After completing the boot process the radio will be ready to receive configuration information. Before the radio can be used to transmit or receive application specific information (network traffic) it must first be configured for the network that it will be used on.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 1. The Network View, which graphically displays the EZCom-IP, radios in the network. 2. The Control Tabs that can be used to change configuration settings and initiate diagnostic functions. 3. The Monitor, which can be used to observe specific communication events. When you first start the Grayhill EZCom-IP Explorer your will see a single icon in the Network View. This icon represents the computer that is running the GH Explorer program.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Point-to-Point Link Example In this first example we will set up a point-to-point link between two Ethernet networks. For simplicity we have represented both networks as consisting of one PC and one EZCom-IP radio (router). In reality a point-to-point configuration could be used to connect anything from a single PC and router to a fully developed enterprise network.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 and the PC. After the PC and radio have gone through their normal boot process you should see a green link indicator (see Figure 20, on page 43). If you do not see the green link indicator please follow the steps in the troubleshooting guide for “No Ethernet Link”. Now that we have a physical connection between the client PC that will be running the EZCom-IP Explorer and an EZCom-IP radio we can begin to setup our first example.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Once the searching process is complete press OK to return to the EZCom-IP Explorer main window. Figure 4, EZCom-IP Explorer After Finding a Radio Explorer Icon EZCom-IP Radio The Explorer should now look like the one shown in Figure 4, above. Don’t worry if the IP addresses and other data on your screen are not exactly as shown. What is important is that there is an EZCom-IP radio icon below the GH Explorer icon in the Network View.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Don’t worry if you do not fully understand each of the settings that you are about to enter, we will cover each of the settings in more detail in the technical reference section latter in this manual. Now click the Radio Tab. You should not have to change any settings on this tab. All of the factory defaults settings should be fine. You may just want to look over the values and verify that they match those shown if Figure 6.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Setting Up The Second PC & Radio Now that we have completed setting up our first PC and an EZCom-IP radio we will need to repeat the steps we followed with the second PC and radio. For the second PC and radio use the setup information listed in the last column of Table 2 on page 6.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Figure 9, Link Test Dialog When the Link test is complete you should see the test results in the Link Test dialog similar to the results shown in Figure 9. If your Link Test fails, that is you don’t get a large number of Successful packets (typically 90% to 100%), please follow the steps listed in the Troubleshooting guide on page 50.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Windows operating system and in essence enables the PC it’s running on to act as a file and/or print server. To enable file and printer sharing on your computer 1. Click on the Start Button and select Settings and Control Panel. 2. After the Control Panel dialog box opens double-click the Network icon. 3. Click File and Print Sharing. 4. Select the check box for the “I want to give others access to my files”, sharing option.
Grayhill EZCom IP Users Manual Rev A6 Windows TCP/IP Set Up Follow these instructions to install the TCP/IP protocol on your PC only after a network card has been successfully installed. These instructions are for Windows 95 and Windows 98. For TCP/IP setup under Windows NT or Windows 2000, please refer to your operating system manual. 1. Click the Start button. Choose Settings, then Control Panel. 2. Double-click the Network icon. Your Network window should pop up. Select the Configuration tab. 3.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Multipoint Store-&-Forward Example This second example is designed to demonstrate in detail how to setup and utilize the routing functions available within a TCP/IP network using the EZCom-IP radio. It may not be practical to setup this example because it requires at least 4 EZCom-IP radios, 4 PCs, and a WAND router.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 are part of the same network. The IP style network ID is 192.168.0.0 with a subnet mask of 255.255.255.0. Therefore the third byte of the IP address is the subnet ID. The individual subnets are simply identified as (.1), (.2), (.3) & (.4). All of the devices on all four subnets have the same subnet mask 255.255.255.0. The IP addresses for each of the devices in the network are listed in Table 4 below.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Now for subnet (.1), first we will need to set both the PC’s and radio’s default gateways to 192.168.1.3. This will insure that all packets not specifically addressed to one of our subnets be forwarded to the Internet router. Next we need to add routes to the radio’s routing table for all packets destined for one of our subnets. This will entail entering three separate routes as shown in Table 5 below. Table 5, Routing Table for 192.168.1.
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Grayhill EZCom IP Users Manual Section 2. Rev A6 1/26/2001 Technical Reference Introduction The technical reference section of this manual is intended to develop a basic overview on the subject of network technology, sufficient in detail to explain the routing function of the EZCom-IP radio. It is not intended to be an exhaustive coverage of the subject but it dose burrow in to some detail of the lower level protocols.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Protocols And Protocol Architecture When computers and/or other data processing devices such as PLC’s exchange data, there must be a data path between the two computers, via a communication network. Although, a data path alone is not sufficient to establish communications, more is needed. Typically the following tasks also need to be performed: 1. The source system must inform the communication network of the identity of the desired destination system. 2.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 A Simple Model In very general terms, data communications can be said to involve three agents: applications, computers, and networks. The applications execute on computers that can often support multiple simultaneous applications. The computers are connected to the network, and the data to be exchanged is transferred by the network from one computer to another.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 information to be used by the peer transport protocol at computer B. Examples of items that may be stored in this header include • Destination application. When the destination transport layer receives the transport protocol data unit, it must know to whom the data are to be delivered. • Sequence number.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 network with the address of the destination computer, so that the network may route the data to the appropriate destination. The network access layer is concerned with access to and routing data across a network for two end systems attached to the same network. In those cases where two devices are attached to different networks, procedures are needed to allow data to traverse multiple interconnected networks. This is the function of the Internet layer.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 TCP/IP Communications The TCP/IP Protocol Stack In the previous section we introduced the concept of Protocol Architecture and we described the basic structure of the TCP/IP protocol stack. In this section will take a closer look at some of the individual protocols associated with the TCP/IP protocol stack. Most of our attention will be focused on the Internet Protocol (IP) because it is responsible for routing of information on a TCP/IP network.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 The main functions of TCP are: • Session establishment • Byte stream communications • Sliding windows Session Establishment Applications using the TCP protocol must be able to open, close, and check the status of sessions to allow them to communicate. To perform this function, TCP uses a three-way handshake. The handshake is important not only to create the session, but also in allowing the hosts to exchange data about their capabilities.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 included in the TCP header of each and every segment sent. A host that is communicating sets the size of its send window to match the other host’s receive window. If you look at the data being transmitted, you would see a series of bytes. If you overlay a window at the start of the data, you can see that a portion of the data falls into the window. This is the only data with which the TCP layer can work.
Grayhill EZCom IP Users Manual • • • Rev A6 1/26/2001 Messages that require no acknowledgment. Using UDP can reduce network overhead. Simple Network Management Protocol (SNMP) alerts fall into this category. On a large network, considerable SNMP alerts are generated because every SNMP device transmits status updates. Seldom, however, is loss of an SNMP message critical. Running SNMP over UDP, therefore, reduces network overhead. Messages between hosts are sporadic. SNMP again serves as a good example.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 octet or byte. To understand TCP/IP and some of the concepts that make it work, it is important to be familiar with the binary form of the address. Understanding binary is relatively easy. Look at the number 238, for example. In conventional math, this is two hundred and thirty-eight. Automatically, you see the 2 as two groups of one hundred, the 3 as three groups of ten, and there are eight groups of one.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Figure 13, IP Address Formats 0 Network (7 bits) 10 Network (14 bits) 110 Host (16 bits) Network (21 bits) 111 Class A Host (24 bits) Host (16 bits) Class B Class C Extended Addressing Class Format undefined Because the Class A addresses use only the first octet to identify the network ID, there are a limited number of them (126, to be exact; 127 is reserved).
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 not, it needs to look for a route to the host. This will be done in the routing table. We will take a closer look at the routing table in just a minute. For now lets look at the logic used to find a route in the routing table first.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Routing Table All devices that use the IP protocol have a routing table, which includes the EZCom-IP radio. In some cases a host’s, routing table does not contain much routing information, except for the default gateway (router) address. In this case any packet not on the local network is normally sent to the default gateway. IP on the gateway then looks in its routing table for a route to the remote network.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 The ROUTE Utility Program Syntax for the ROUTE command is as follows: Manipulates network routing tables. ROUTE [-f] [command [destination] [MASK netmask] [gateway] [METRIC metric]] -f Clears the routing tables of all gateway entries. If this is used in conjunction with one of the commands, the tables are cleared prior to running the command. -p When used with the ADD command, makes a route persistent across boots of the system.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Finding Another Machine’s Address Whether a packet that you are sending is going to a host on your network or to a host on a remote network, the packet is always sent to a MAC address (the hardware address of the network card). The only difference in sending to the local or the remote network is that the address used for a remote network is the address of the router on the local network.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 This might seem a little severe. Entries in the ARP cache, however, are the hardware addresses of the network cards in other hosts. This could very possibly change for a given host, and would (if your entries were permanent) require all the hosts to be updated. ARP Utility Program To work with your ARP cache, you can use the ARP command.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Ethernet Physical Layer As we have mentioned before the EZCom-IP radio is essentially an Ethernet IP router. It is not necessary to fully understand how Ethernet works to utilize the EZCom-IP radio just as it is not necessary to understand the internal workings of a combustion engine to drive a car. However for those interested there is a description of media access procedure for Ethernet in appendix B.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Subnetting Subnetting is the process of dividing a network into smaller sections or segments; with each segment having it’s own IP subnet address. Subnetting is not necessary in all situation, but it will greatly reduce the number of routing table entries that you will have to create and maintain. It will also improve the overall network performance by reducing the time it takes for each radio to lookup a route when forwarding packets.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Table 12, Extracting a Network ID Using a Standard Subnet Mask IP Address Subnet Mask Network ID 160.16.45.3 255.255.255.0 160.16.0.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 1100. It takes 4 bits to write the number 12 in binary. To allow for at least 12 unique binary combinations, therefore, you need to use 4 bits for your subnet mask. You can add the bits to the standard subnet mask to generate a custom subnet mask. When the bits are added to the subnet mask, all the required bits are set to 1. In the class B example used earlier, it would look like Table 15.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 possible combinations exist in the subnetted octet. Looking at them as an entire octet, they can be converted to decimal. This gives you the subnet IDs. Table 17 shows the calculation of subnet IDs using binary.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Knowing that you need 28 subnets, the obvious answer is to use 5 bits for subnetting-as you can see, that this gives you up to 30 subnets. You might, therefore, use the 255.255.248.0 as the subnet mask. This leaves 3 bits for hosts in the third octet plus the 8 in the last for a total of 11 bits. That works out to 2,046 hosts per segment. Finding the end of the valid host IDs is also simple.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 EZCom IP Routing Introduction Routing is the primary function of an EZCom IP radio. The routing scheme implemented in the EZCom IP radio is modeled after the same routing mechanism used on the Internet. In fact the EZCom-IP radio can be used to route private network or Internet information. Figure 18 below shows a simplified view of the processing an EZCom-IP radio performs when it receives network traffic.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Table 24, Typical EZCom-IP Radio Routing Table Target 192.168.1.0 192.168.4.12 Subnet Mask 255.255.255.0 255.255.255.255 Next Hop 192.168.1.2 192.168.4.1 Interface Radio Radio Origin Local Each EZCom-IP radio has a routing table in memory that it searches each time it receives a datagram to send. Each entry in the routing table contains the following information: • Destination IP Address.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 EZCom IP routing is done on a hop-by-hop basis. As we can see from the information stored in the routing table, EZCom IP dose not know the complete route to any destination (except, of course, those destinations that are directly connected via the network or the RF port). All IP routing provides is the IP address of the next-hop router to which the datagram is sent. It is assumed that the next-hop router is really “closer” to the destination.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 Indicators and Connectors The following indicators are provided on the face of the EZCom-IP radio. Figure 20, EZCom-IP Indicators M in Signal Mode RX Max Power Link Status TX • Signal is a series of 10 indicators that represent receive signal strength. When illuminated red indicates uncorrelated signal. Green is correlated. • Mode indicates 1 meg/sec or when green 2 meg/sec. • Power when illuminated indicates power is on.
Grayhill EZCom IP Users Manual Section 3. Rev A6 1/26/2001 Grayhill EZCom-IP Explorer Program Introduction The Grayhill EZCom-IP Explorer is a client side program that can be run on any 32 bit Windows based PC. It is designed to communicate configuration and diagnostic information to and from a group of EZCom-IP radios either directly to the local area network or logically attached via the wireless network. The program offers the user a verity of configuration and diagnostic tools.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 GH Explorer will then add a radio icon to the Network View for each radio it finds on the local network. The information in the Control Tab window is associated with the icon selected in the Network View. As you click on different icons in the Network View the information in the Control Tab View is updated with the setup values from the object represented by the selected icon.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 The Disconnect menu item is used to delete a radio from the Network View. When you select Disconnect you are telling the Explorer program that you no longer want to communicate with the radio selected in the Network View. Disconnect only effects the radio selected in the Network view and any other radios that are listed below it. When there are mutable instances of the same radio in the network view you can use Disconnect to delete the unwanted duplicates.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 The Update Button is used to upload any changes you have made on the IP Address tab to the currently selected radio. Any change that you make on this tab will not take effect until you click on the Update button. Radio Tab The Radio Tab is used to set the operating characteristics for the currently selected radio.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 The form of the Subnet Mask is dependent on the type of destination address entered in the previous step. If the destination address is a host address then the subnet mask will always be 255.255.255.255. On the other hand if the destination address is a network address the subnet mask will be the mask implemented on the destination network.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 The Link Test can be used to verify the quality of communications between two radios. To use the link test function first select the radio that you want to initiate the link test, from the Network view. Then Click on the Link Test button, this will bring up the Link Test dialog as shown below. Now enter the Mac Address of the radio you want to link to and click on the Run Test button.
Grayhill EZCom IP Users Manual Section 4 Rev A6 1/26/2001 Troubleshooting Guide LED Activity B If you encounter difficulty using and/or installing your EZCom-IP product, the error may be related to various causes: • Out-of range situation, which prevents the EZCom-IP radio from establishing a wireless connection with the network. • Configuration mismatch, which prevents the EZCom-IP radio from establishing a wireless connection with the (correct) network.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 need to isolate and correct the mismatch. Typically poor VSWR readings are caused by poorly installed cable connectors. Some times if there is a Polyphaser used for lightning suppression they can go bad and cause a poor VSWR. 4. If the 2 radios are separated by a large distance say a few miles or more try running a link test to a closer in radio or possibly a spare radio if one is available.
Grayhill EZCom IP Users Manual Appendix A. Rev A6 1/26/2001 Ethernet (CSMA/CD) The most commonly used medium access control technique for bus/tree and star topologies are carrier-sense multiple access with collision detection (CSMA/CD). The original baseband version of this technique was developed by Xerox as part of the Ethernet LAN. The original broadband version was developed by MITRE as part of its MITREnet LAN. All of this work formed the basis for the IEEE 802.3 standard.
Grayhill EZCom IP Users Manual Rev A6 1/26/2001 transmitting, one after the other, and none of their frames get through unscathed. Suppose, however, that the propagation time is small compared to frame transmission time. In that case, when a station launches a frame, all the other stations know it almost immediately. So, if they had any sense, they would not try transmitting until the first station was done.
Grayhill EZCom IP Users Manual Rev A6 3. If a collision is detected during transmission, transmit a brief jamming signal to assure that all stations know that there has been a collision and then cease transmission. 4. After transmitting the jamming signal, wait a random amount of time, and then attempt to transmit again. (Repeat from step 1.