Ethereum interface

1. Eth interface refers to the interface, is the most widely used LAN communication mode, but also a protocol. Ethernet interface is the port of network data connection
each version of Ethernet has a maximum cable length limit (that is, the length without amplification). Signals within this range can propagate normally, and signals beyond this range cannot propagate
in order to allow the construction of a larger network, repeaters can be used to connect multiple cables. Repeater is a physical layer device, which can receive, amplify and retransmit signals in two directions
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several common Ethernet interface types
1. SC optical fiber interface
SC optical fiber interface has been applied in the era of 100base TX Ethernet, so it was called 100base FX at that time (F is the abbreviation of optical fiber). However, at that time, because the performance was not more prominent than twisted pair, but the cost was higher, so it was not popularized. Now the instry vigorously promotes gigabit network, and SC optical fiber interface is re valued
2. RJ-45 interface
this kind of interface is the most common network equipment interface, commonly known as "crystal head", and the professional term is RJ-45 connector, which belongs to the type of twisted pair Ethernet interface. RJ-45 plug can only be inserted along the fixed direction, and a plastic spring piece is set to be stuck with RJ-45 slot to prevent it from falling off
3. FDDI interface
FDDI has the highest transmission rate among the mature LAN technologies. It has the characteristics of timed token protocol, supports a variety of topologies, and its transmission medium is optical fiber. Fiber distributed data interface (FDDI) is a set of protocols developed by American National Organization for Standardization (ANSI) to transmit digital signals on optical cables
reference source: Network Ethernet interface

2. curl方法，file_get_contents,

3.

If you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records

the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:

< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){
transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />});

Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query

recommend a practical introction, you can see: Ethereum tutorial

4.

The con port is the console interface, which is directly connected to the serial port of the computer by using the console cable. The router is configured locally by using the terminal emulator (generally using the "super terminal" of windows)

eth port is Ethernet interface, and Ethernet interface is the port of network data connection, which connects different computer devices together. The basic elements of Ethernet equipment networking include switch, router, hub, optical fiber and common network cable, Ethernet protocol and communication rules

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switches that can be used for network management generally have a "console" port, which is specially used for the configuration and management of switches. Connecting and configuring the switch through the console port is a necessary step to configure and manage the switch

because other configuration methods often need the help of IP address, domain name or device name, and it is obviously impossible for newly purchased switches to have these parameters built-in, so the console port is the most common and basic switch management and configuration port

console ports of different types of switches are located in different positions, some on the front panel and some on the back panel. Generally, molar switches are mostly located on the front panel, while fixed configuration switches are mostly located on the back panel. On the top or side of the port, there will be a sign similar to "console"

Ethernet interface types: SC optical fiber interface, RJ-45 interface, FDDI interface, AUI interface, BNC interface, console interface

5. The Ge port is a Gigabit Ethernet port, and the ETH port is a fast Ethernet port, that is, a 100M Ethernet port.

6. Through curl to simulate, and then get the data, and use it in JSON format

7. Ppp0 should be connected to the cat. There is no problem with the connection of computers in the eth0 world. There is no speed priority at the exit of the router itself. It is all the same.

8. The optical fiber cat has two interfaces, pots and eth.
the ETH interface refers to the broadband Internet interface, which is used when you connect the network cable of the computer or router

9. In recent years, Cisco's high-end routers have basically adopted IOS XR system instead of the original IOS system; The original IOS system has a variety of simulators to simulate, a variety of play; However, it seems that there are not many options for IOS XR simulation. You can download the IOS xrv-k9-demo-5.2.0 file (the version is not necessarily 5.2.0) from the Cisco official website, and use VMware to run and simulate the IOS XR system
however, when I first used it, I encountered a problem, that is, the router simulated by IOS XR only has two physical interfaces: mgmteth0 / 0 / cpu0 / 0, and gigabitethernet 0 / 0 / 0 / 0, which is obviously not enough to play
therefore, under VMware, add the [network adapter] of the virtual machine. No matter how much you add it, the number of physical interfaces in the IOS XR system is always the same. What can you do
the solution is as follows: IOS XR virtual machine in my document, under the corresponding folder, there is a file: xxxxx.vmx, which corresponds to the name of the virtual machine. Use WordPad to open (Note: do not use Notepad to open and edit, because this will cause an error to be reported when running the virtual machine at last, and prompt "dictionary error"). In this document, there are some information about IOS XR physical interface, such as:
Ethernet0. Present = & quot; TRUE"< br />ethernet0.virtualDev = " e1000"< br />ethernet0.connectionType = " bridged"< br />ethernet0.startConnected = " TRUE"< br />ethernet0.addressType = " generated"< br />ethernet0.generatedAddress = " 00:0c:29:1c:1d:34"
in this document, the number of Ethernet is consistent with the number of network adapters in the virtual machine. According to the MAC address of each Ethernet in the document, it can correspond to each network adapter in the virtual machine. Therefore, as long as the [network adapter] of the virtual machine is added, the number of Ethernet in this document will be increased, and the corresponding configuration will be added
however, the problem to be solved in this paper is rooted in a command: Ethernet0. Virtualdev = & quot; e1000"， By default, this command is available for Ethernet 0 and Ethernet 1, but not for other physical interfaces such as Ethernet 2 and Ethernet 3. Therefore, the router virtualized by IOS XR has no corresponding physical interface. By adding the following commands, we can solve the problem of unable to add physical interface of Router:
Ethernet 2. Virtualdev = & quot; e1000"< br />ethernet3.virtualDev = " e1000"
you can add [network adapter] in the virtual machine according to your own test needs, and add the above command in the VMX file, save the document, open it again, and you can see that the physical interface of the IOS XR router has increased, As follows
RP / 0 / 0 / cpu0: XR? Sho IP int bri
Thu Jul 16 22:45:55.638 UTC

interface IP address status protocol
mgmteth0 / 0 / cpu0 / 0 unassigned shutdown down
gigabitethernet 0 / 0 / 0 unassigned up
gigabitethernet ET0 / 0 / 0 / 1 unassigned shutdown down
gigabitethernet 0 / 0 / 0 / 2 unassigned shutdown down
gigabitethernet 0 / 0 / 0 / 3 unassigned shutdown down
note that when modifying the VMX document, you need to close the virtual machine first, save the closed document, and then open the virtual machine
when IOS XR virtual machine is just started, it is relatively slow, and it takes a long time to load the configuration, and the previous configuration can not be saved. As long as you wait for a period of time, you can resume normal use.