determined by the physical characteristics of the Ethernet. This 1500 byte is called the MTU (maximum transmission unit) of the link layer ). The Internet Protocol allows IP sharding so that data packets can be divided into small fragments to pass through links with the maximum transmission unit smaller than the original size of the data packet. This fragment process occurs at the network layer. It uses the value of the maximum transmission unit that
counted as a group? What's the point of each signal bit?
This is the function of the "link layer", which determines how 0 and 1 are grouped above the "solid layer".
3.2 Ethernet Protocol
In the early days, each company had its own way of grouping electrical signals. Gradually, a protocol called "Ethernet"(Ethernet) occupies a dominant position.
Ethernet requires that a set of electrical signals constitute a packet called "frame". Each frame is divided into two parts: header (head) and data.
sectionsHead contains: (fixed 18 bytes)
Sender/Source Address, 6 bytes
Recipient/Destination Address, 6 bytes
Data type, 6 bytes
Data contains: (minimum 46 bytes, maximum 1500 bytes)
Details of the packet
Head length +data length = Shortest 64 bytes, up to 1518 bytes, over maximum limit on shard send
MAC Address: Ethernet Specifies that devices that are connected to the Internet
will receive all multicast packets in the network-A displays all interface information-S Display summary information (similar to netstat-i)Add to configure the IPV6 address for the specified NICDel deletes the IPV6 address of the specified network cardmtunetmaskTunel establishing a tunnelDSTADDR set a remote address to establish point-to-point communication-broadcast-pointtopointMulticast setting the multicast flag for the network cardAddress sets IPV4 addresses for network cardstxqueuelen4. Us
interface.The ARP setting specifies whether the NIC supports the ARP protocol.-promisc sets whether the promiscuous mode of the NIC is supported, and if this parameter is selected, the NIC will receive all packets sent to it in the network-allmulti Settings Support multicast mode, if you select this parameter, the NIC will receive all multicast packets in the network-A displays all interface information-S Display summary information (similar to netstat-i)Add to configure the IPV6 address for th
We are bound to encounter a situation where Bank A and bank B open your account almost at the same time and see the original 1000 Yuan deposit on your account, and both banks want to add a 500 yuan deposit to your account. Then, bank A will change 1000 yuan to 1500 yuan, at the same time, Bank B will also change 1000 yuan to 1500 yuan. This is going to be a bad thing! Finally, your bank account at the end o
1. Enter your own salary to calculate the personal income tax: according to the current tax rate (find your own tax rate)
public static void Main (string[] args) {System.out.println ("Please enter your salary:");Scanner sc=new Scanner (system.in);Double money=sc.nextdouble ();Double total=0.0;total=money-3500;Double revenue=0.0;if (totalSystem.out.println ("Congratulations, no watering");}else if (totalrevenue=total*0.03;}else if (total>1500totalrevenue=1500
I feel the same way, but. cn domain name has been cnnic do rotten, in fact, it seems that this is not a personal webmaster anything, in the end, in fact, or cinnic!
OK, back to the theme, talk about my investment in some ideas, I have done Oh! Did you have a note today? Oh please look down
I have been crazy registering more than 1500 these days is not very bad. cn Domain Name purpose is to do garbage station! Oh, I now have more than 10 servers on e
on users;
User created.
SQL> GRANT CREATE SESSION, CREATE ANY TABLE, ALTER ANY TABLE,
2 drop any table, lock any table, select any table,
3 create any index, CREATE ANY TRIGGER
4 to tj;
Grant succeeded.
SQL> GRANT EXECUTE_CATALOG_ROLE TO TJ;
Grant succeeded.
2. Log On with the TJ user and create a table DEMO. As the original table for online redefinition, add a primary key and an index to the table.
SQL> conn tj/tj
Connected.
SQL> create table demo as select empno, ename, sal, deptno from scott
We will surely encounter this situation: Bank A and Bank B open your account almost simultaneously and see the original 1000 yuan deposit in your account, then both banks want to add a deposit of 500 yuan to your account. Then, Bank A will change 1000 yuan to 1500 Yuan, and Bank B will also change 1000 yuan to 1500 yuan. This is terrible! In the end, your bank account has only
of the real Nic is 1500.We know that for openvpn, it is best to set the MTU at both ends to be consistent. In the case that we are unlikely to change the MTU of the real network before and after openvpn, Tun basically sends and receives messages based on around 1500 of the data, although completely simulating network behavior, however, it is fundamentally different from the real network environment. In the
thousand of household appliances and furniture (some women are charged for dowry ).
4. Cars, based on ordinary scooter, are counted as 0.1 million. Some well-intentioned Nanjing girls also agreed to use electric vehicles as a substitute, totaling 1500 yuan.
5. xi jiu, taking 25 mid-sized hotels as an example, includes self-built wine, cigarettes, sugar, and 1200 × 25 = 30 thousand. The average RMB 1200 for each table is used to collect red packets, w
the way of interpretation: how many electrical signals to calculate a group, the meaning of each signal?This is the function of the link layer, which, on the physical layer, determines how the 0 and 1 are groupedEthernet protocol:Ethernet provides that a set of electrical signals constitute a packet called "frame", each frame is divided into 2 parts, header (head) and data"Header" contains some description of the packet, such as sender, recipient, data type, etc., "data" contains specific conte
transmits the first packet (3000-3499), so the receiver finds a duplicate, and then returns a sack=3000-3500 because the ACK is 4000 means that all data before 4000 is received. So this SACK is d-sack--is designed to tell the sender that I received duplicate data, and our sender also know that the packet is not lost, the missing is the ACK packet.
1 2 3 4 5 6 7
Transmitted Received ACK SentSegment Segment (Including SACK Blocks)3000-3499 3000-3499 3500 (ACK dropped)3500-3999 35
, two Ack is lost, so the sending end multiplicity transmits the first packet (3000-3499), so the receiver finds a duplicate, and then returns a sack=3000-3500 because the ACK is 4000 means that all data before 4000 is received. So this SACK is d-sack--is designed to tell the sender that I received duplicate data, and our sender also know that the packet is not lost, the missing is the ACK packet.
1234567
transmitted received ACK Sent segment segment (Including SACK Block
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