Network Connectivity And Management

NETWORK CONNECTIVITY AND MANAGEMENT AT HCL Info-Tech Systems Jaipur By

Manmohan Garg [email protected]

INTRODCTION • Representation of a network: Types and topologies of networks. • OSI reference model. • Network components and their features. • Data-Center internal connectivity. • UPS Connectivity in the Data-Center. • Network management. • Scope of improvement. • References.

TYPES OF NETWORKS • LAN – Local area network is a small geographical area such as our school board.

• MAN – Metropolitan area network is a network over a larger geographical area such as the provincial government.

• WAN – Wide area network is a network used over an extremely large geographical area such as the federal government.

Representation of a network 2.Physical Topologies

2. Logical Topologies

NETWORKS ARE BROKEN INTO 3 TOPOLOGIES. • BUS TOPOLOGY Allows information to be directed from one computer to the other. Lots of binary collision though.

2. STAR TOPOLOGY is the most common type used. All computers are attached to a hub. Less collisions and most efficient.

3. RING TOPOLOGY Uses a token to pass information from 1 computer to the other.

• A disadvantage of a token ring is if one computer is broken or down, the message cannot be passed to the other computers.

OSI reference Model The Open Systems Interconnection Basic Reference Model.

THE PHYSICAL LAYER It is concerned with transmitting raw bits over a communication channel though hubs, wires (cat5UTP), modems, network card.

CAT5 cable Speeds up to 100 Mbps.

COMMUNICATION CHANNELS

When looking at network cables in the way the wire ends are connected within the RJ45. 3.Straight though cables

2.

Cross-over cables

Crimping Tool

Hubs • Hubs are layer 1 devices. They regenerates the signal and broadcast it out all the rest of their ports. • Classifications of hubs 4.Active or Passive hubs. 5.Intelligent or Dumb hubs.

THE DATA-LINK LAYER The data link layer takes raw transmission and transforms it into a line that appears free of transmission errors in the network layer. • There are smart devices such as switches in the Data-Link Layer. • These devices takes decision on the MAC address.

• Data link layer sends frames small fixed length pieces of data.

SWITCH • A switch is a Layer 2 device. • They make decisions based on MAC addresses.

• Switches make decisions based on the MAC table.

THE NETWORK LAYER The network layer is concerned with controlling the operation of the subnet.

IP Address • An Internet Protocol address is a logical address that is assigned to devices participating in a computer network utilizing the Internet Protocol for communication between its nodes.

IP Address

Structure of an IP address

Subnet mask It is used to identify the network and host bits in an IP address.

Broadcast Address It is used to send data to all of the devices on a network. • Broadcast IP addresses end with binary 1s in the host part of the address. • Class B Broadcast Address Example: 176.10.255.255

Loopback The IP address 127.0.0.1 is used as the loopback address. It is used by the host computer to send a message back to itself.

Subnetting Subnetworks are smaller divisions of networks. • Subnet addresses are locally assigned by a network administrator. • Subnets reduce a broadcast domain.

Subnet Addresses • It has Class A, B, or C network portion plus a subnet field and a host field. • For subnet field Bits are borrowed from the host field

• The minimum number of bits we can borrow is two.

Calculating Subnets • We will subnet the IP address: 223.14.17.0 3.What class IP address is this? Class C 4.Class C default subnet mask: 255.255.255.0 5.Let we Need: 13 subnets 10 hosts on each subnet

Now we have to determine how many bits to borrow from the host ID.

• For the 4 bits borrowed each bit can be a 1 or a 0 leaving you with 24 or 16 possible combinations. • The same goes for the 4 leftover host bits.

But there are only 14 available subnets and hosts on each subnet. • Because you cannot use the first and last subnet. • Last one is the broadcast address and first one is the network address. To get the new subnet mask we will Add the place values to get 128 + 64 + 32 + 16 = 240 the last octet decimal value of the subnet mask.

The ranges of host addresses for each subnet.

ROUTERS • A router is a Layer 3 device. • It Forwards data depending on the Network address (IP), not the Hardware (MAC) address. • The purpose of a router is to examine incoming packets (Layer 3 data), choose the best path for them through the network. • It works in LAN, MAN and WAN environments.

• It is used to connect networks.

• It Limits the collision domain

THE TRANSPORT LAYER •

•

•

It provide logical communication between applications processes running on different hosts. It transport protocols that runs in end systems. Sender side: it breaks application messages into segments, passes to network layer. Receiver side: it reassembles segments into messages, passes to application layer. It has more than one transport protocol available to applications : TCP and UDP.

• Reliable, in-order delivery: TCP Connection-oriented and acknowledgment.

THE SESSION LAYER • The session layer allows different machines to establish sessions between them. • The Session layer provides the mechanism for managing the dialogue control and token management end- user application processes. • It provides communication between systems in simplex mode, half duplex and full duplex mode.

THE PRESENTATION LAYER • The presentation layer is responsible for the delivery and formatting of information to the application layer for further processing or display. • If any packets got lost along the way, or were damaged, then the presentation layer will send a sign to the sender that it requires the specific packet.

THE APPLICATION LAYER • It interfaces directly to and performs common application services for the application processes; it also issues requests to the presentation layer. • It has many end-user protocols to perform various tasks. • FTP - File Transfer Protocol It provides a standard system for sending and receiving files over IP networks.

• HTTP Protocol Web browsers and servers use the Hypertext Transfer Protocol (HTTP) protocol to communicate. • DHCP The Dynamic Host Configuration Protocol (DHCP) supports automatic address assignment and improved configuration management of IP

• IPv6 - Internet Protocol version 6 IPv6 promises to relieve the current IP address shortage, and this new version of the protocol may also increase performance and improve administration capabilities.

DATA CENTER INTERNAL CONNECTIVITY

RRVPNL 2*5 KVA UPS Status – (Rack Wise) Pw. Board 1 Pw. Board 2

Pw. Board 3

Pw. Board 4

Pw. Board 5

Pw. Board 6

• . UPS1

UPS2

UPS1

1A 1B

2A

4 Cooling 100 Fan 325

DNS

100

325 Firewall

UPS2

UPS1

3A 3B

San Switch 325

80

4 Cooling 100 Fan

325

325

Switch 325 250

250 San Storage

325

Appli. 1

Database 1

5A 5B

60 Cisco L3 Switch

Cisco L3 Switch

Web 1

UPS2

4A 4B

4 Cooling 100 Fan 60

325 Mail/SMTP

325

UPS1

4 Cooling 100 Fan

325

17” Color 100 325 Monitor 325

UPS2 2B

325 325 325 325

6A 6B

4 Cooling Fan File 1

Web 2

325

17” Color Monitor

100

Appli. 1

325

Database 1 325

File 2

4 Cooling Fan 17” Color Monitor

T&D Database

File 3

External DNS Linux

T&D Application

Pw. Board 7

UPS1

UPS2

4 Cooling Fan

7A 7B 60

Cisco L3 Switch

100

1A,2A,3A,4A,7A Power load on UPS No. – 1 1B,2B,3B,4B,7B Power load on UPS No. – 2 Power load of Cooling fans, Servers, Monitors, Switches shown in this diagram in Watts

APPLICATION SERVER • An application server is a software engine that delivers applications to client computers or devices, typically through the Internet and using the Hypertext Transfer Protocol. • The application server combines or works with a web (hypertext transfer protocol) server and is called a web application server .

DATABASE SERVER • A database server is a computer system or program that provides database services to other computers or computer programs. • Database servers store the database on a dedicated computer system, allow it to be accessed concurrently, maintain the integrity of the data, and handle transaction support and user authorization.

Domain Name System (DNS) Server • A DNS stores information such as the list of mail servers that accept email for a given domain. By providing a worldwide keyword-based redirection service, the Domain Name System is an essential component of contemporary Internet use. • For example: www.google.co.in, into IP addresses, e.g.

FILE SERVER • In the client/server model, a file server is a computer responsible for the central storage and management of data files. so that other computers on the same network can access the files. • A file server allows users to share information over a network without having to physically transfer files by floppy diskette or some other external storage device

MAIL SERVER • A mail server is an application that receives incoming e-mail from local users (people within the same domain) and remote senders and forwards outgoing e-mail for delivery. • As a rule, the system uses SMTP (Simple Mail Transfer Protocol) or ESMTP (extended SMTP) for sending e-mail, and either POP3(Post Office Protocol 3) or IMAP(Internet Message Access Protocol) for

PROXY SERVER • A proxy server is a server which services the requests of its clients by forwarding requests to other servers. • The proxy server provides the resource by connecting to the specified server and requesting the service on behalf of the client

NETWORK MANAGEMENT Network management is the ability to control and monitor a computer network from a central location. It covers a wide area, including: • Security: Ensuring that the network is protected from unauthorized users. • Performance: Eliminating bottlenecks in the network. • Reliability: Making sure the network is available to users

TROUBLESHOOTING • Verifying the problem Narrow the scope 1. Try multiple websites 2. Try multiple services (browser, email, IM) 3. Put 146.186.157.6 in browser. Tests TCP/IP and gateway connection Tests DNS

Finding the problem • Try websites from another PC If problem exists on another machine Indicates problem outside of PCs

• Check all cabling • Reboot router and modem If problem isn’t on another machine Indicates problem on your PC 1. Check cabling at both ends. 2. Check TCP/IP settings. 3. Reboot PC.

Possible improvements in the RRVPNL network 2.No of routers can be increased: 3.DHCP server was not present 4.Backbone cable can be upgraded to fiber cable which support speedy data transfer. 5.Authentication methods can be useful

Thank You.