[Linux] Network Knowledge Summary

MTU Max transmission Unit
The basis of transmitting shards in IP layer

ICMP can simply be considered as the most basic control message of IP

Ping uses answer requests and replies to echo two types

Tracert leverages the TTL and ttlexceeded types of the IP

There are seven types of NIC binding modes in Linux: 0. Round robin,1.active-backup,2.load Balancing (XOR), 3.fault-tolerance (broadcast), 4.LACP, 5.transmit load balancing, 6.  Adaptive load Balancing. corresponding Bond0~bond7 respectively

What do you call OpenFlow?
Building a crash-prevention internet
In layman's terms, it is a subproject of the big project Gini that re-design the next generation of network protocols from the source.
Allow the Internet to adapt to changing loads and dynamically adjust the path based on the spikes in network traffic.
OpenFlow the control flow meter in the router by the algorithm rules;
One of the most important advantages of openflow is that it can change the way packets are transmitted over the network
OpenFlow extends the flow table set on the switches and routers, while providing an open protocol for configuring flow table on different switches and routers.
OpenFlow Switch's data path contains a flow table and each flow entry corresponding operation.

echo 7 >/PROC/SYS/KERNEL/PRINTK height log level

Renaming the NIC
IP link set Dev eth4 name eth4.vf0

Linux device drivers have two ways of loading insmod and modprobe, and here's how they differ in usage
1, Insmod can only load a specific device driver at a time, and need to drive the specific address. The wording is:
Insmod Drv.ko
2. Modprobe can load all dependent drivers into the kernel at once. No driver-specific address, but you need to install the driver module in the same way as make Modues_install when installing the file system. The drive is installed in the/lib/modules/$ (uname-r)/... Under The wording is:
Modprob DRV

Network Card Disorderly Order:
Remove rules from/etc/udev/rules.d/70-persistent-net.rule reload driver

Binding interrupts
Cat/proc/interrupts |grep Eth3
echo 0 >/proc/irq/118/smp_affinity
Echo 1 >/proc/irq/119/smp_affinity

Kernel compilation
zcat/proc/config.gz >. config
Make Menuconfig
Make-j 14
Make modules
Make Modules_install
Make install

There are three VLAN modes on the port: Access mode, trunk mode, and hybrid mode. When a user makes a VLAN configuration for a port, the VLAN mode of the port must first be specified.

The port in Access mode is an access port that is directed to the user, which can only belong to a untagged member of a VLAN. The default VLAN is the user-specified VLAN. When a port belongs only to a untagged member of a VLAN, you can specify that the port's VLAN mode is access mode.

Trunk mode port is a trunk port, directly connected to the switch, which can belong to the tagged member of one or more VLANs, but not the untagged member of any VLAN, the default VLAN of this port is 1 and cannot be changed.

The port in hybrid mode is a trunk port that is directly connected to the switch, which can belong to the tagged member of one or more VLANs and/or untagged member of one or more VLANs. The default VLAN for this port can be changed.

Query the file list of RPM packages RPM-QPL xxx.rpm
Query the file list of installed RPM packages RPM-QL xxx
Query installs a package Rpm-qa | grep xxx
Install XXX package RPM-IVH xxx.rpm
Uninstall XXX package Rpm-e xxx
Query the RPM package for a file RPM-QF filename
RPM Package Forced installation--nodeps--force

The core file generation method is modified:
echo "Ulimit-c Unlimited" >>/etc/profile
. /etc/profile
echo "./core-%p-%e-%t" >/proc/sys/kernel/core_pattern
echo "1" >/proc/sys/kernel/core_uses_pid

Permission interpretation
777 Rwxrwxrwx
644 rw-r--r--
666 rw-rw-rw-

A three-digit number represents 9-bit permissions, divided into 3 sections,
The first 3 bits represents the owner's permissions,
The second section, 3 digits, represents the same group of user rights,
Part Three 3-bit represents other user rights,

R for Read permission equals 4,w on behalf of Write permission equals 2,x on behalf of EXECUTE permission equals 1

Change the Linux boot interface level
/etc/inittab

View Linux veneer version information
Cat/etc/issue

View CPU Information
Cat/proc/cpuinfo

Modification Time: Date-s
Modify Time zone: Cp/usr/share/zoneinfo/asia/shanghai/etc/localtime

Format image
DD If=/dev/zero of=./test bs=1024 count=1000

Set swap partition size
1, set up the swap space file dd If=/dev/zero of=/home/swap bs=1024 count=2048000
2, set into swap swap space Mkswap/home/swap 2048000
3. Activate the swap space Swapon/home/swap

If the swap space is included in the/etc/fstab, it can be used automatically.
/dev/hda8 None swap SW 0 0 # #注意, if you are using separate partitions to set up swap, then join this line
/swapfile None swap SW 0 0 # #否则, make a swap with the file, then join the line. Just one line

Swap Setup Recommendations:
4GB or 4GB of memory system, the minimum need 2GB swap space;
More than 4GB and less than 16GB of memory system, the minimum need 4GB swap space;
More than 16GB and less than 64GB of memory system, the minimum need 8GB swap space;
Systems that are larger than 64GB and less than 256GB of memory, require 16GB swap space minimum

[Linux] Network Knowledge Summary