Ethereum TX
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
extended data
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
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
After reading the answers of other respondents, I really want to laugh. It's not terrible to pretend that I don't understand. What's terrible is to answer blindly. There's something wrong with this question. The burst of 5.7 billion yuan has nothing to do with a drop of 10 cents. It can even be said that its disappearance is e to the sharp rise. So where is the decline? If bitcoin really falls, it will not be 5.7 billion capital washed away, it will be tens of billions, hundreds of billions of capital evaporated, those who talk about trends and development, please study the capital and stock market well, and by the way, please search for the meaning of the word "burst", no culture is too terrible
in addition, I would like to make a digression. Recently, a hot topic is fund. In 2021, the annual meeting is more or less a national fund. In 2020, the fund manager is still a good active fund. Even if the position is not changed, the annual yield will reach at least 40%, but this does not mean that this year is still OK, It's not that everyone can make money playing with funds. it's similar to the nature of stocks. Index funds, stock funds and even active funds are risky. I think many people say that they should get on the bus quickly. They are really worried about your funds of course, 2021 may be a bull market. It is estimated that the whole network has spread, many people are rubbing their hands to make a lot of money, but I can't do much. I just advise you not to go with the flow too much, don't be greedy, and don't think you are. That's all. Good luck
eth0 to awk for processing
where - F & # 39;:|< br />+'
this is a separator defined by awk and then matched with "BCAST & quot;, Take the content of the fourth column
since your command is not universal, you can't output the result here, but you should intercept the broadcast address
however, different switches may be slightly different. For example, for some switches, the green light indicates that the network is normally connected, the green light indicates that there is data transmission, and the yellow light indicates that although the physical line is connected, there is a problem with the IP address or other settings, and the network is not normally connected; Also (it seems to be D-Link). The green light indicates normal communication. If a port is connected to a cascade switch, the receiver of this port will display a yellow light......... As long as the network can communicate normally, these are not particularly important, if you want to understand clearly, look for the relevant instructions to see it!!!
lo, which is the same as that of many Cisco routers! This Lo address, this is a logical address, does not exist physically, so like Cisco router, it means never drop line
many devices developed based on Linux, such as Shenxin technology, have a universal address, and this universal address is lo address!
whether it is installed automatically or manually, Linux will ask you questions about the network and configure relevant software. The basic command used to configure the network card is ifconfig
after executing the ifconfig command, the system will set the necessary parameters in the kernel table, so that Linux knows how to communicate with the network card on the network. The ifconfig command has the following two formats:
* ifconfig [interface]
* ifconfig interface [aftype] option | address...
the first format of ifconfig (or use the ifconfig command without any parameters) can be used to view the network configuration of the current system
just after the system is installed, Linux is actually used without network card or network connection, but through ifconfig, you can use loopback mode to make the computer think that it is working on the network
now let's run the ifconfig command. The ifconfig command without parameters can display the currently started network interface, The output results are as follows:
[ root@machine1 /sbin]#ifconfig
eth0 Link encap:Ethernet Hwaddr 52:54:AB:DD:6F:61
inet addr:210.34.6.89 Bcast :210.34.6.127 M ask:255.255.255.128
UP BROADCAST RUNNING MULTICAST MTU:1500 M etric:1
RX packets:46299 errors :0 dropped:0 overruns :0 frame:189
TX packets:3057 errors :0 dropped:0 overrun s:0 carrier:0
c ollisions:0 txqueuelen :100
I nterrupt:5 Base address:0xece0
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask :255.0.0.0
UP LOOPBACK RUNNING MTU:3924 M etric:1
RX packets:44 errors :0 dropped:0 overruns :0 frame:0
TX packets:44 errors :0 dropped:0 overruns :0 carrier:0
c ollisions:0 txqueu elen:0
the part headed by eth0 is the configuration parameters of the local Ethernet card, which shows the device name / dev / eth0 under the network card and the MAC address of the hardware 52:54: ab: DD: 6F: 61. The MAC address is determined by the manufacturer, and each network card has a unique address< However, we can manually change the MAC address of the NIC, as long as we add:
ifconfig eth0 HW ether XX: XX: XX: XX: XX: XX: XX in / etc / rc.d/init.d /, which represents NIC 1 and NIC 2, Network card 3
HW stands for hardware
ether stands for Ethernet Ethernet
then restart. At this time, check with ifconfig command, and we will find that the MAC address of network card has changed to XX: XX: XX: XX: XX: XX
the IP setting method of the following network card:
set it directly through setup
configure multiple network cards ifconfig - A to view network devices eth0 / eth1 / Lo (loops)
ifconfig eth1 / / device 1
ifconfig eth1 192.168.1.10 netmask 255.255.255.0 / / setting subnet and IP of NIC
man ifconfig
ifconfig -- help (T002)
therefore, RX and TX are accumulated upward from reset and recalculation after power on.