Basics of networking
A network can set of autonomous computer networks to facilitate communication and networking at the same time, the simple concept of connected computers are connected to define.
Networks and networking has grown exponentially over the past 15 years, have evolved to keep pace with the speed of light with only a huge increase needs critical summary of utilities such as sharing data and printers, and advanced needs such as videoconferencing.
TYPESNETWORKS
Local area network (LAN)
A LAN (Local Area Network) is a group of computers and network devices connected together, usually within the same building. A Local Area Network (LAN) is developing high-speed communications system for connecting computers and other computing devices together in a small geographical area, such as a workgroup, department or building. Networks together to implement local access technology. This means that all devices connected to shared LANa sole means of communication, usually a coaxial cable, twisted pair or fiber optic cable.
Metropolitan Area Network (MAN)
Metropolitan Area Network or MAN are large computer networks usually spans a city or a country. Normally, the use of wireless infrastructure or optical fiber connections to link their Web sites.
The IEEE 802-2001 standard describes a man as: "A man is optimized for a wider geographical area of a LAN, ranging from several blocks of buildingsentire cities. MAN may also moderate the communication channels need high speeds. A man can be owned and operated by a single organization, but is typically used by many individuals and organizations. MAN might be owned and operated as public services. They often provide the means for internetworking of local networks. Metropolitan Area Network may extend up to 50 km. "
Wide Area Network (WAN)
Wide Area Network (WAN) is a computer network covering awide area. A WAN is limited compared to a man, not a place, although it could be restricted to a geographical location may also be restricted within the boundaries of one state or country. A WAN connects several LANs and is a company (a company or organization) or to limit the audience.
The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN.
NETWORKINGDEVICES
ROUTER
Routers are used in network and pass along data packets from a network connection to another. Routers by default break broadcast domain, that the set of all devices on a network segment that all mail is sent to listen to this segment.
Routers also break up collision domains. This is an Ethernet term used to describe a network scenario where a particular device sends a packet on a network segment, forcing every other device in this segmentWatch for it. At the same time trying to transfer to another device, causing a collision, after which both devices must be repeated at a time.
Router level 3 of the OSI model (Open System Interconnection) reference model run.
SWITCHES
The switches are used to segment the network based on MAC addresses. Switches to look at the hardware addresses incoming frame before the decision, forward or drop the frame.
Switches collision domains, butthe hosts of the switch are still members of a large broadcast domain.
HUB
A hub is actually a multiple port repeater. A repeater receives a digital signal and then amplified or regenerated signal and transmit the digital signal on all active ports without looking at all the data. An active hub does the same. This means that all devices connected to a hub in the same collision domain and broadcast domain itself, which means that the devices share thesame bandwidth. work on the physical hub of the OSI model.
IP addresses
An IP address is a numerical identifier for each machine an IP network. It designates the specific location of a networked device. An IP address is an address and software designed to host on a network with a host on a different network, regardless of the type of LAN to communicate with the technicians involved in.
IP terminology
Bit: A bit 'is a digit, either a 1 ora 0
Byte: A byte is 7 or 8 bits, depending on whether parity is used.
Octet: An octet, consisting of 8 bits is made just a normal 8-bit binary number. In most cases, byte and octet are fully interchangeable.
Network Address: This is the description of routing packets to a remote network used for sending. For example, 10.0.0.0, 172.16.0.0, and 192.168.10.0 is the network address.
Broadcast address: The address of the host applications and used for sending informationall nodes on a network as a broadcast address. Examples include 255.255.255.255, all networks, all nodes is 172.16.255.255, which is all subnets and hosts on network 172.16.0.0.
Hierarchical IP addresses
An IP address consists of 32 information bits (IPv4). IPv6, a new version of IP consists of 128 bits of information. The 32-bit IP is divided into four sections known as an octet or byte, each containing 1 byte (8 bits).
An IP address is representedUse one of these three methods.
Dotted decimal notation, as in 172.16.30.56
Binary, as shown in 10101100.00010000.00011110.00111000
Hexadecimal, as in AC.10.1E.38
All these examples represent the same IP address. But the most commonly used is the dotted decimal notation. The Windows Registry stores the IP address of a machine in hexadecimal.
The 32-bit IP address is an address or hierarchical structure to a flat hierarchical address of the contract. Although both species could have the addressing schemebeen used, hierarchical addressing was chosen for good reason. The advantage of this approach is that there are a large number of addresses, namely 4.3 billion (a 32-bit address space with two possible values for each position to deal with 1 or 0 returns 237 or 4294967296).
The disadvantage of the addressing system refers to the routing plan. If every address is unique, all routers on the Internet would have the address of each computer in the internet shop. Thatefficient routing impossible.
Network Address RANGE
The network address uniquely identifies each network. Every computer on the same network shares that network address as part of its IP address. The IP address 172.16.30.56, the network address is 172.16.
The node address is assigned and uniquely identifies each computer on a network. This number can be defined as a host address. The node address 172.16.30.56 is 30.56. Class A network is used when asmall number of networks have a very large number of nodes are mandatory. Class C network is used when a large number of networks is necessary with a small number of nodes.
Class A addresses
The first bit of first byte in a Class A network address must always be turned off or 0. This means that a class A address must be 0-127 inclusive.
0xxxxxxx.hhhhhhhh.hhhhhhhh.hhhhhhhh
If we take the other 7 bits all off and then turn each time, we find the class A range of networkAddresses.
00000000 = 0
01111111 = 127
Class-A network.node.node.node format is, for example, the IP address 49.22.102.70, the 49 is network address and 22.102.70 is the node address. Each machine on the network should be the distinctive network address of the 49th
Class B addresses
The first bit of first byte must be on time, but the second bit must be turned off forever.
01xxxxxx.xxxxxxxx.hhhhhhhh.hhhhhhhh
If we turn ourThe first bit and the second is now, and the other six pieces all out and then we are all the range of Class B network addresses to find.
10000000 = 128
10111111 = 191
Class B-format is now network.network.node.node IP address 132.163.40.57, which is the network address and 132.163 40.57 is the node address.
Class C addresses
The first and second bits of the first byte must be on time, but the third bit can neveron.
110xxxxx.xxxxxxxx.xxxxxxxx.hhhhhhhh
If we turn the bit on first and second and third bits, and then all the other 5 bits to all and all, find the range of network addresses Class C
11000000 = 192
11011111 = 223
Class C consists network.network.network.node, for example, the IP address 195.166.231.75, which is 195 166 231 the network address and 75 is the address of the node.
Class D and Class E addresses
The address is 224-255reserved for Class D and E networks Class D (224-239) is used for multicast addresses and E-Class (240-255) for scientific purposes.
Private IP addresses
Private IP addresses are those that can be used in a private network, but are not routed on the Internet. This is for the purpose of creating a well-designed safety measure required, but also conveniently saves valuable IP address space. If every computer in each network was real IP addresses for routing, wewill run from IP addresses to hand years ago.
Class A 10.0.0.0 to 10.255.255.255
Class B 172.16.0.0 to 172.31.255.255
Class C 192.168.0.0 to 192.168.255.255
IP address problem
Here is the troubleshooting procedure in solving a problem is on an IP network.
First Open a DOSWindow ping 127.0.0.1. This is the diagnostic or loopback address, and if you get a successful ping, your IP stack is initialized. If it fails, then you have an IP stack failure and need TCP / IP to be installed on the machine.
From the second DOS window, ping the IP addresses of local hosts. If this has happened, then your Network Interface Card (NIC) card works. If it fails, then there is a problem with the NIC. This does not mean that a cable is connectedthe NIC, only that the IP protocol stack for the host to communicate with the NIC.
Third From the DOS window, ping the default gateway. If the ping works, the network is connected to the network and can communicate on the local network. If it fails, then you have a local problem, the physical network could happen anywhere from the NIC to the gateway.
Fourth If steps 1-3 are able, try to ping the remote server. If this works then you have IP communicationthen between the local computer and the remote server, you also know that the remote physical network.
Fifth If you can not even with the server after steps 1-4 have been conducted to communicate, then there is probably a resolution problem, and you must check the domain name server (DNS) settings.
Network Address Translation
Network Address Translation (NAT) to translate primarily at private addresses in a network of a global address outside. The main ideais the Internet address to save space, but increases the internal network security by hiding IP addresses from external networks.
TABLE 3: NAT ADVANTAGES AND DISADVANTAGES
BENEFITS
Conserves legally registered addresses.
Reduces address overlap event.
Increases flexibility when connecting to the Internet.
Delete address renumbering the network changes.
Translation switch port path delays
DISADVANTAGES
The loss ofEnd-to-end traceability
Some applications will not be enabled with NAT.
Types of NAT
Static NAT This type of NAT is designed so that one-to-one relationship between local and global addresses. Static NAT assumes that there is a real Internet IP address for each computer on the network.
Dynamic NAT: This version offers the ability to map an unregistered IP address to a registered IP address from a pool of registered IP addresses.
Overload:This is also known as Port Address Translation (PAT). It 's the most popular type of NAT configuration. Overloading is a form of dynamic NAT, which maps the different IP address is not recorded on a single IP address registered with other ports. With thousands of users can overload the Internet through only one real global IP address to establish.
NAT Terminology
Local Phone Numbers: local hostname first translation.
General Contact: Name Address forTranslation.
Within local name in the source address before translation.
Outside the zone: the name of the destination host before translation.
Inside Global Name Interior houses the translation
Outside global name of the destination host outside after translation.
Layer2 SWITCHING
Layer2 switching is the process by which the hardware address of devices on a LAN segment to a network. The term Layer 2 switching is used because the shift to services, data-link layerWhat is the second layer of the OSI reference model.
Layer2 switching is a bridge, because hardware-based special hardware as an application specific integrated circuit (ASIC) is used. ASICs can run up to gigabit speeds with very low latency rates.
Switches read each frame that passes through the network, the Layer 2 device, then the hardware address of origin in a filter table and keeps track of which was received in the door frame. Information (recordedswitch the filter table) is what helps the machine determine the location of a specific sending device. After a filter table Layer2 device built, it will only forward frames to the segment is located in the target hardware. If the target device on the same segment as the frame, the frame of layer2 locking device to another segment. If the destination is in another segment can be transferred to the frame only to this segment. This is calledTransparent Bridging.
Interface when a switch receives a frame with a destination hardware address that is not in the table filter unit, forward the frame to all connected segments found. If the unknown device that the frame is sent responses to this forwarding action, updates its table to pass the filter on the device now.
BENEFITS OF SWITCHING Layer2
The biggest advantage of LAN switching hub centered implementations is that each device on eachSegment on a switch can transmit silmatenously while hubs allow only one device for each network segment to communicate at a time.
Switches are faster than routers because they do not take time to look at the network layer header information. Instead, they regard the context of the hardware before deciding to fall forward or let the frame.
Switches to create collision domains and private dedicated bandwidth independent of any other hub ports. The figure belowshows five hosts connected to a switch, with all 10Mbps half-duplex to the server. Unlike the hub, each host has 10Mbps dedicated communication to the server.
LIMITATIONS OF SWITCHING Layer2
switched networks break collision domains, but the network is still a large broadcast domain. This means not only the limits of your network size and growth potential, but could also reduce overall performance.
Switching function Layer2
There are three different functionsLayer2 Switching, such
E-learning.
Forward / filter decision
Loop avoidance.
E-learning
When you first switch on the MAC / filter table is supplied empty. If a device sends and receives an interface to the frame, the switch sets the source address MAC frame forward / filter table, so he thought, the interface for sending unit is located. The switch then has no choice but to network with this picture of high tideeach port except the source port because it has no idea where the target device is actually located.
If a device answers and sends a flooded frame frame, then switch the source address of a frame and place the MAC address in its database and this also address associated with the interface that received the frame. Since the switch now has the MAC address filtering is appropriate in its table, the two devices is now a connection point to point. TheSwitch does not need to flood the frame as did the first time.
If there is no message to a specific address within a certain time, the sensor will flush the entry from the database in order to keep as current as possible.
FORWARD / FILTER DECISIONS
When a frame arrives at a switch interface, the target hardware address forward / filter MAC database compliance. If the target hardware address is known and listed in the database, the frame is sentonly the correct output interface.
The switch does not transmit the frame any interface except the interface target. This saves on the segments of the broadband network and other is called FRAME filtering.
LOOP PREVENTION
When two switches connected to each other, redundant connections between switches are a good idea, because to prevent failure of complete network if a link is no longer needed.
redundant links are very useful, but often cause moreThe problems than they solve, it is because the frames are all redundant links silmatenously create network loops are flooded.
Switches use a protocol called STP (Spanning Tree Protocol) created by Digital Equipment Corporation (DEC) for Compaq hours to avoid network loops stop redundant connections. With STP running, frames will only be forwarded to the premium collected STP link.
FAMILY CONFIGURATION Cisco Catalyst 2950 Switch.
The 2950 is a Cisco Catalyst switchswitch family of high-end model. The 2950 is available in many flavors and 10Mbps run all the way up to 1 Gbit / s switched ports with either twisted pair or fiber optics. You can use basic data, video and voice services.
STARTUP 2950
If the 2950 is switched on, it runs through a Power-On Self Test (POST). First, any port LEDs are green, and determines whether the end of the post, that all ports are in good condition, all LEDs blink and then go off again. But if the post is aPort system that has failed both the LED and port LEDs turn amber.
But unlike a router, the switch can actually be used in fresh-out-of-the-box state. You can simply connect the switches in the network and network segments together without any configuration.
To connect to the Cisco switch, use an Ethernet cable to connect a variety rolled to a switch console serial port. After connecting the correct cable from the PC to the Cisco switch, you canStart a HyperTerminal console connection and configure the device to create as follows:
First Open HyperTerminal by clicking the Start button, point to All Programs, then Accessories, then Communication, then click HyperTerminal. Enter a name for the connection. No matter how you call. Then click OK.
According to Select the communication port COM1 or COM2, if you open your PC.
Now the third port settings. The default values (2400bps and no flow control hardware)does not work, you showed the port settings as shown below.
Note that the bit rate is set to 9600 and the current is set to None. At this point, you click OK, then press the Enter key, and you should be connected to your Cisco Switch console port.
Here is the 2950 edition of 'original:
--- --- System Configuration Dialog
Look for the initial configuration dialog? [Yes / No]: no
Press RETURN to get started!
00:04:53:% LINK-5-Changed: Interface VLAN1 changed administratively Down State
00:04:54:% LINE PROTO-5-UPDOWN: Line Interface Protocol VLAN1, and the evolving situation down
Switch>
CONFIGURATION
Switch> prompt means of user EXEC mode and is usually used to display statistics. You can view and change only the configuration of a Cisco switch in privileged EXEC mode, allowing command.
Switch>
Switch>allow
Switch #
Switch # disable
Switch>
The global configuration mode, configure the privileged mode with the terminal command or config t for short can be entered.
Switch # config t
Enter configuration commands, one per line, ending with CNTL / Z.
Switch (config) # hostname Zenith
Zenith (config) #
The hostname command is used to designate the switch. The host name of a switch is significant only locally, but is still useful to set a host namea switch that allows you to locate the switch when you connect.
SETTING THE PASS LINE mode active word and PASSWORD.
Zenith> Enable
Zenith # config t
Enter configuration commands, one per line, ending with CNTL / Z.
Zenith (config) # enable password bank
Zenith (config) # enable secret center
The bank enable password command sets the password how to enable the bank and the enable secret command sets the secret password to activate the media center. The resultingsecret password is more secure, and replace the password if it is set to Allow. The enable password and enable secret password can not be the same switch in 2950
Zenith (config-line) #?
First line number
Console Primary terminal line
vty Virtual terminal
Zenith (config) # line vty?
First line number
Zenith (config) # line vty 0 15
Zenith (config-line) # login
Zenith (config-line) # password alex
Zenith (config-line) #line with 0
Zenith (config-line) # login
Zenith (config-line) # password Malouda
Zenith (exit config-line) #
Zenith (config) # exit
Zenith #
Line vty 0 15, a login and password alex command sets the telnet password for Alex, and the line with 0 password and Malouda Malouda is to forget the console commands.
Setting of IP information
You have set any IP configuration on the switch so that it works. You can connect only a. But there are twoReasons we set the switch IP address information.
To manage the switch via Telnet or other management software.
To configure the switch with VLANs and various networking features.
Zenith (config) # int vlan 1
Zenith (config-if) # ip address 172.16.10.17 255.255.255.0
(Zenith config-if) # no shutdown
Zenith (config-if) # exit
Zenith (config) # ip default-gateway 172.16.10.1
Zenith (config) #
The IP address is 172.16.10.17 and enter Noimplement the shutdown command to enable the interface.
Configure the interface specifications
You can administratively set a name for each interface of the button with the name of order.
Zenith (config) # int FastEthernet 0 /?
Fastethernet number.
Zenith (config) # int FastEthernet 0 / 1
Zenith (config-if) # description LAN Sales
Zenith (config-if) # int f0/12
Zenith (config-if) # description connection to the mail server
Zenith (config-if) #CNTL / Z
Zenith #
You can with descriptions at any time, even with the show command or the show running-config interface command from global configuration mode for research.
Delete and save the configuration SWITCH
Zenith # copy running-config startup-config
Zenith # erase startup-config
The first command copies the configuration in NVRAM (nonvolatile RAM), while the command erase startup-config deletes the switch configuration.
Zenith # cancelstartup-config
Clearing the NVRAM file system to remove all files! Next? [Confirm] [Enter]
[OK]
Erase NVRAM: all
Zenith #
Virtual LAN (VLAN)
A virtual LAN (VLAN) is a logical grouping of network users and resources is linked administratively defined ports on a switch. When you create VLANs, creates a small broadcast domains within a switched internetwork by assigning different ports on the switch different subnets. A VLAN istreated as its own subnet or broadcast domain, which are sent frame switched network only between the ports logically grouped in the same VLAN means.
By default can not communicate with hosts on a specific VLAN with other hosts that are members of another VLAN.
5.1 ADVANTAGES OF VLAN
A group of users can be secure in one VLAN, so that no users outside the VLAN can communicate with them are made.
As a logical grouping of users can run VLANsbe independent of their physical location or geographical area.
VLANs improve network security.
It 'can block broadcast storms caused by a faulty NIC (Network Interface Card) card.
VLANs increase the number of broadcast domains, decreasing their size.
VLAN membership
VLANs are usually the administrator who then assigns switch ports are created for each VLAN. This VLAN is VLAN as static. If the administrator wants a bit 'of work to do tobefore and have all your hardware devices host addresses in a database, then the switch can be configured to dynamically assign VLANs, when a host will make a switch. It is a dynamic VLAN.
VLAN STATIC
Static VLANs are the usual way of creating VLANs, and are also the safest. The door switch, VLAN assignment association always say that the association until an administrator manually changes the port assignment.
Dynamic VLANs
AVLAN dynamic VLAN determines the allocation of a node automatically. With intelligent software, you can base the mapping of hardware addresses, protocols, applications or to create dynamic VLANs.
An example of a VLAN Management Policy Server (VMPS) is the service used to establish a database of MAC addresses that can be used for dynamic addressing of VLANs. A VMPS database maps MAC addresses to VLANs.
Frame Tagging
As frames are switched through the network, you must passbe able to keep track of all the images. Frames depending on the type of bond that is cross processed. The identification method uniquely assigns structure ID defined for each frame. This is sometimes as VLAN ID.
Each switch must first ensure that the picture frame out of the VLAN tag ID, and then figure out what to do with the framework, adding the information in the table filter. When the frame reaches a switch that has another trunked radioLink, the door frame connecting parents are forwarded.
Once the structure reaches out to an access link in matching the VLAN ID, the switch removes the VLAN ID. This is therefore the target device, the frame can be understood without its VLAN ID to receive.
There are two different types of links in a switched environment, which are:
access link: This type of link is only part of a VLAN. Each device is connected to nothing access connection to a VLANMembers, the device simply takes his share of the broadcast domain. Access link devices can not communicate with devices outside their VLAN if the packet is forwarded.
Link Trunk: Trunk links can carry multiple VLANs. A link is a trunk of 100 or 1000 Mbit / s point to point connection between two switches between a switch and server. These carry the traffic of multiple VLANs 1-1005 at a time. Trunking allows you to make one side of the door multiple VLANs at the same time. It also allowsVLAN span multiple switches.
VLAN identification methods
There are basically two types of coding frame.
Inter-Switch Link (ISL)
IEEE 802.1Q
The main purpose of ISL and 802.1Q Frame Tagging methods is to allow communication inter-switch VLANs.
Inter-Switch Link (ISL) Protocol: This is the property of Cisco switches and is used for Fast Ethernet and Gigabit Ethernet links only. ISL routing can be used on a switch port, router interfacesserver interface cards to trunk a server.
IEEE 802.1Q: Created by the IEEE as a standard method of coding structure is not Cisco proprietary trunking, if you're between a Cisco switched link and go to another brand, You Have to 802.1Q for the trunk link to use . work
VLAN Trunking Protocol (VTP)
This protocol was developed by Cisco, but is not the owner. The basic goals of VLAN Trunking Protocol (VTP) are to manage all configured VLANs across a switchedInter net and consistency of the network. VTP allows an administrator to add, delete and rename VLANs on a switch, the information is then propagated to all other switches in VTP domain.
Before being able to VTP VLAN on the network, you must create a VTP server. All switches in the same VLAN information must be the same VTP domain.
You can with a VTP domain if there is more than one switch connected in a network, but when all switchesOnly in a VLAN, no need to use VTP. VTP information between switches on trunk port in September
No comments:
Post a Comment