Report on Router

FINAL REPORT ON ROUTER 1

ContentsINTRODUCTION:...................................................................................................................................2

How routers work....................................................................................................................................7

Like a postal system or courier ......................................................................................................8

Routing Protocol ......................................................................................................................................9

Types of routing protocol .....................................................................................................................9

Enhanced Interior Gateway Routing Protocol (EIGRP) .......................................................10

Interior Gateway Routing Protocol (IGRP) ..............................................................................11

TYPES OF ROUTERS:........................................................................................................................11

Broadband Routers: ..........................................................................................................................11

Wireless Routers: ..............................................................................................................................12

OTHER TYPE ROUTERS:.................................................................................................................14

EDGE ROUTER:................................................................................................................................14

SUBSCRIBER EDGE ROUTER:..................................................................................................14

INTER-PROVIDER BORDERS ROUTER:...............................................................................14

Core Router.........................................................................................................................................15

Advantage and Disadvantage of Routers .......................................................................................15

Advantage:...........................................................................................................................................15

Easily Shared Internet .....................................................................................................................15

Security and Adaptabil i ty ...............................................................................................................16

Disadvantage: .....................................................................................................................................16

Complicated Setup............................................................................................................................16

Data Overhead....................................................................................................................................16


INTRODUCTION:

A router is a device that forwards data packets between computer network

creating an overlay internetwork. A router is connected to two or more data lines

from different networks. When a data packet comes in one of the lines, the

router reads the address information in the packet to determine its ultimate

destination. Then, using information in its routing table or routing policy, it

directs the packet to the next network on its journey. Routers perform the

"traffic directing" functions on the internet . A data packet is typically forwarded

from one router to another through the networks that constitute the internetwork

until i t reaches its destination node.

The most familiar type of routers are home and small office routers that simply

pass data, such as web pages, email, IM, and videos between the home

computers and the Internet. An example of a router would be the

owner's cable or DSL modem, which connects to the Internet through an ISP

More sophisticated routers, such as enterprise routers, connect large business or

ISP networks up to the powerful core routers that forward data at high speed

along the optical fiber lines of the internet background. Though routers are

typically dedicated hardware devices, use of software-based routers has grown

increasingly common. Routers are very common today in every network area,

this is mainly because every network these days connect to some other network,

whether it 's the Internet or some other remote site. Routers get their name from

what they do.which is route data from one network to another. Routers capture

the information that come through broadband connection via a modem and

deliver it to your computer The router choose route for the packet so that you

receive the information Firstly. Routers are multiport devices and more

sophisticated as compared to repeaters and bridges. Routers also support

filtering bridges. They operate at physical, data link and network layer of OSI

model.


Like bridges, they are self learning, as they can communicate their existence to

other devices and can learn of the existence of new routers, nodes and LAN

segments.

A router has access to the network layer address or logical address (IP address).

It contains a routing table that enables it to make decisions about the route i .e.

to determine which of several possible paths between the source and destination

is the best for a particular transmission. These routing tables are dynamic and

are updated using routing protocols.

The routers receive the packets from one connected network and pass them to a

second connected network. However, if a received packet contains the address of

a node that is on some other network (of which the router is not a member), the

router determines which of its connected networks the best next relay point for

that packet is. Once the router has identified the best route for a packet to

travel, it passes the packet along the appropriate network to another router. That

router checks the destination address, find what it considers the best route for

the packet and passes it to the destination network.

Router is a network communication device that is used to connect logically and

physically different networks. It can be used in the Ethernet, FDDI, Token Ring,

ATM, Frame Relay, ISDN and other types of the LAN/WAN. The router’s main

purpose is the sorting and distribution the data packets. Router contains and

maintains the routing table that has the information of the adjacent routers and

other connected networking devices. Router selects the shortest possible path to

send the data packets at the destination. It is an intelligent device that can

connect ATM with Frame Relay, ISDN with Frame Relay, SONET with ATM or

any other two dissimilar networks. Router uses different protocols such as RIP

(Routing Information Protocol), OSPF (Open Shortest Path First) and BGP and

IGRP (Interior Gateway Routing Protocol) and EIGRP (Enhanced Interior

Gateway Routing Protocol. Routing protocols specifies that how routers will

communicate with each other in the WAN.


They determine that which path to select to send the data towards its

destination. There are three main types of the routing protocols i .e. link state,

path vector and distance vector. Router contains the operating system, Flash

memory, NVRAM and processor. High level routers contain the Application

Specific Integrated Circuits to perform parallel processing. A router is also act

as a gateway that connects LAN with the internet

For home and business users that use the high speed DSL connection a router

also act as a hardware firewall device. It filters and blocks the unwanted traffic

based on the IP address, port, protocol, application and service. Before buying

router for deploying in your home or office network make sure it is compatible

with other devices in your networks. It is recommend that you buy and deploy

the all the network devices from the same vendor.Computers that specialize in

sending packets over the data network.They are responsible for interconnecting

networks by selecting the best path for a packet to travel and forwarding packets

to their destination Function of router is to take out the destination IP address

from the packet and determines the next network point to which a data packet

should be forwarded towards its destination.Before reaching the destination

from source, packet may have to follow a long path, in between it may go

through many routers, like first router may send it to second and so on number

may rise up to 10 to 20 routers.


Data is sent in form of packets between 2 end devices

Routers are used to direct packet to its destination

There are two major groups of router interfaces

LAN Interfaces:

1: Are used to connect router to LAN network

2: Has a layer 2 MAC address

3: Can be assigned a Layer 3 IP address

4: Usually consist of an RJ-45 jack


WAN Interfaces:

1: Are used to connect routers to external networks that interconnect LANs.

2: Depending on the WAN technology, a layer 2 address may be used.

3: Uses a layer 3 IP address

In such cases router can act as hardware firewall, i t does not allow computer’s

IP address to directly expose to the internet A router work at layer 3 on OSI

Model and have functions on Layer 4 (filtering ACL, NAT) and don't perform

any scan on Hosts. Basically, He only route packets so only know the

source/destination IP and if the PC is on a subnet directly connected he know

the MAC address. Some routers can capture packet or monitoring and by this

information you can determine Port of a Host. If you use overloaded an

encrypted VPN can prevent the reading of information of packets.


How routers work

A router passes data between multiple networks. It works at the “layer 3” (the network link layer),

which means that it must be able to understand the data packets so that it can route them to their destination.

Routers are essentially computers optimized for handling packets that have


to be transferred between separate networks. Routers attempt to send packets from their source to their destination in the fastest way possible, which is not always the absolute shortest path.

On a network, packets with destinations on the LAN go directly from the sending machine to the destination machine without any intermediaries. However, if the destination address of a packet is outside the LAN, the sending machine sends it to the router, which the sending machine knows as the default gateway, and has no further interaction with that packet.

When the router receives a packet destined for a point outside the LAN, it looks to see if it has a route to get the packet to that destination network. If it does (or if it has a default gateway of its own), it will send the packet to the next stop.

Like a postal system or courier

Routing between a LAN and a wide-area network (WAN) is like a postal system or a courier network. A package traveling from New York to San Francisco might travel through a hub in Memphis or Chicago and be re-sorted in Reno before heading to its final destination. If the package had to be hand-delivered quickly, you could do that, but the cost would increase significantly, and hopefully, the package won't get routed the long way around, because that tends to be inefficient and difficult to trace.

In the same manner, routers send packets according to the available routes between networks and try to determine the shortest possible route at any given time.

How does a router do this? Well, inside a router is a set of data called routing tables. Routing tables include:

• All possible routes the router is aware of Information on which connections lead to particular groups of addresses

• Priorities for connections to be used Rules for handling both routine and special cases of traffic

Routing tables are dynamic — they are updated by routing protocols such as Routing Information Protocol (RIP) or Open Shortest Path First (OSPF) that constantly pass messages between routers. The router


consults them to determine whether or not it has a route to a particular destination address.

Routing Protocol

A routing protocol specifies how routers communicate with each other, disseminating information that enables them to select routes between any two nodes on a computer network. Routing algorithms determine the specific choice of route. Each router has a priori knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network.

Although there are many types of routing protocols, three major classes are in widespread use on IP networks:

Interior gateway routing via link state routing protocols , such as OSPF and IS-IS

Interior gateway routing via distance vector routing protocols , such as RIPv2, IGRP and EIGRP

Exterior gateway routing . The Border Gateway Protocol (BGP), a path vector routing protocol , is the routing protocol used on the Internet for exchanging traffic between Autonomous Systems.

Many routing protocols are defined in documents called RFCs

Some versions of the Open System Interconnection (OSI) networking model distinguish routing protocols in a special sub layer of the Network Layer (Layer 3).

The specific characteristics of routing protocols include the manner in which they avoid routing loops, the manner in which they select preferred routes, using information about hop costs, the time they require to reach routing convergence , their scalability, and other factors.

Types of routing protocol

Some of the most common routing protocols include IGRP, EIGRP, OSPF, IS-IS and BGP. There are two primary routing protocol types although many different routing protocols defined with those two types. Link state and distance vector protocols comprise the primary types. Distance vector protocols advertise their routing table to all directly connected neighbors at regular frequent intervals using a lot of bandwidth and are slow to converge. When a route becomes unavailable, all router tables must be updated with that new information. The


problem is with each router having to advertise that new information to its neighbors, it takes a long time for all routers to have a current accurate view of the network. Distance vector protocols use fixed length subnet masks which aren't scalable. Link state protocols advertise routing updates only when they occur which uses bandwidth more effectively. Routers don't advertise the routing table which makes convergence faster. The routing protocol will flood the network with link state advertisements to all neighbor routers per area in an attempt to converge the network with new route information. The incremental change is all that is advertised to all routers as a multicast LSA update. They use variable length subnet masks, which are scalable and use addressing more efficiently.

Enhanced Interior Gateway Routing Protocol (EIGRP)

Enhanced Interior Gateway Routing Protocol is a hybrid routing protocol developed by Cisco systems for routing many protocols across an enterprise Cisco network. It has characteristics of both distance vector routing protocols and link state routing protocols. It is proprietary which requires that you use Cisco routers. EIGRP will route the same protocols that IGRP routes (IP, IPX, use the same composite metrics as IGRP to select a best path destination. As well there is the option to load balance traffic across equal or unequal metric cost paths. Summarization is automatic at a network class address however it can be configured to summarize at subnet boundaries as well. Redistribution between IGRP and EIGRP is automatic as well. There is support for a hop count of 255 and variable length subnet masks.

Convergence

Convergence with EIGRP is faster since it uses an algorithm called dual update algorithm or DUAL, which is run when a router detects that a particular route is unavailable. The router queries its neighbors looking for a feasible successor. That is defined as a neighbor with a least cost route to a particular destination that doesn't cause any routing loops. EIGRP will update its routing table with the new route and the associated metric. Route changes are advertised only to affected routers when changes occur. That utilizes bandwidth more efficiently than distance vector routing protocols.

Autonomous Systems

EIGRP does recognize assignment of different autonomous systems which are processes running under the same administrative routing domain. Assigning different autonomous system numbers isn't for defining a backbone such as with


OSPF. With IGRP and EIGRP it is used to change route redistribution, filtering and summarization points.

Characteristics Advanced Distance Vector Routes IP, IPX Routing Advertisements: Partial When Route Changes Occur Metrics: Bandwidth, Delay, Reliability, Load, MTU Size Hop Count: 255 Variable Length Subnet Masks Summarization on Network Class Address or Subnet Boundary Load Balancing Across 6 Equal or Unequal Cost Paths (IOS 11.0) Hello Timer: 5 seconds on Ethernet / 60 seconds on Non-Broadcast Hold down Timer: 15 seconds on Ethernet / 180 seconds on Non-Broadcast Metric Calculation = destination path minimum BW * delay (m sec) * 256 Split Horizon

Interior Gateway Routing Protocol (IGRP)

Interior Gateway Routing Protocol is a distance vector routing protocol developed by Cisco systems for routing multiple protocols across small and medium sized Cisco networks. It is proprietary which requires that you use Cisco routers. This contrasts with IP RIP and IPX RIP, which are designed for multi-vendor networks. IGRP will route IP, IPX, Decnet and AppleTalk which makes it very versatile for clients running many different protocols. It is somewhat more scalable than RIP since it supports a hop count of 100, only advertises every 90 seconds and uses a composite of five different metrics to select a best path destination. Note that since IGRP advertises less frequently, it uses less bandwidth than RIP but converges much slower since it is 90 seconds before IGRP routers are aware of network topology changes. IGRP does recognize assignment of different autonomous systems and automatically summarizes at network class boundaries. As well there is the option to load balance traffic across equal or unequal metric cost paths.

Characteristics Distance Vector Routes IP, IPX, Decnet, Appletalk Routing Table Advertisements Every 90 Seconds Metric: Bandwidth, Delay, Reliability, Load, MTU Size Hop Count: 100 Fixed Length Subnet Masks


Summarization on Network Class Address Load Balancing Across 6 Equal or Unequal Cost Paths ( IOS 11.0 ) Update Timer: 90 seconds Invalid Timer: 270 seconds Hold down Timer: 280 seconds Metric Calculation = destination path minimum BW * delay (usec) Split Horizon

TYPES OF ROUTERS:

There are several types of routers in the market.

Broadband Routers:

Broadband routers can do different types of things. Broadband routers can be

used to connect computers or to connect to the Internet.

If you connect to the internet through phone and using Voice over IP technology

(VOIP) then you need broadband router. These are often a special type of

modem (ADSL) that will have both Ethernet and phone jacks.

A device that provides access to the Internet for multiple computers. It typically

includes a network switch with four or more Ethernet ports for wired

connections to desktop and laptop computers. "Wireless routers include a wifi

access point The device forwards Internet traffic from the computers to the cable

or DSL modem and switches non-Internet traffic between the connected

machines. It combines a router, network switch and DHCP server (to assign IP

addresses to stations). The router also provides network address translation

(NAT), which allows multiple users to reach the Internet with one public IP

address assigned by the cable or telephone company to the service outers capture

the information that come through broadband connection via a modem and

deliver it to your computer The router choose route for the packet so that you

receive the information Firstly. Routers are multiport devices and more

sophisticated as compared to repeaters and bridges.


A broadband router utilizes the Ethernet standard for wired connections.

Traditional broadband routers required Ethernet cables be run between the

router, the broadband modem, and each computer on the home network.

Wireless Routers:

Wireless routers create a wireless signal in your home or office. So,

any PC within range of Wireless routers can connect it and use your Internet.

In order to secure your Wireless routers, you simply need to come secure it with

password or get your IP address. Then, you'll log on into your router with the

user ID and passwords will that come with your router. A network device that

combines a router, switch and Wi-Fi access point (Wi-Fi base station) in one

box. Wireless routers provide a convenient way to connect a small number of

wired and any number of wireless computers to the Internet. For more about

wireless networks It is commonly used to provide access to the Internet or a

computer network. It does not require a wired link, as the connection is made

wirelessly, via radio waves.

A wireless router is a device that enables wireless network packet forwarding

and routing, and serves as an access point in a local area network. It works much

like a wired router but replaces wires with wireless radio signals to

communicate within and to external network environments. It can function as a

switch and as an Internet router and access point A wireless router is the router

found in a wireless local area network (WLAN) for home and small office

networks. It enables Internet and local network access. Typically, the wireless

router is directly connected to a wired or wireless WAN. Users connected to the

wireless router are able to access the LAN as well as the external WAN, such as

the Internet. Depending on the capabilities of the wireless router, it can support

from a few to hundreds of simultaneous users. Moreover, most wireless routers

can also function as a firewall with the ability to block, monitor, and control and

filter incoming and outgoing network traffic.


It enables you to run a computer or gaming system from anywhere in the house

without having to run cables through the walls.

OTHER TYPE ROUTERS:

EDGE ROUTER:

A router is a device that forwards data packets between computer networks,

creating an overlay internetwork. A router is connected to two or more data lines

from different networks. When a data packet comes in one of the lines, the

router reads the address information in the packet to determine its ultimate

destination. Then, using information in its routing table or routing policy, it

directs the packet to the next network on its journey. Routers perform the

"traffic directing" functions on the Internet. A data packet is typically forwarded


from one router to another through the networks that constitute the internetwork

until i t reaches its destination node

The most familiar type of routers are home and small office routers that simply

pass data, such as web pages, email, IM, and videos between the home

computers and the Internet. An example of a router would be the

owner's cable or DSL modem which connects to the Internet through an ISP.

More sophisticated routers, such as enterprise routers, connect large business or

ISP networks up to the powerful core routers that forward data at high speed

along the optical fiber lines of the Internet backbone. Though routers are

typically dedicated hardware devices, use of software-based routers has grown

increasingly common.

This type of router are placed at the edge of the ISP network, they are normally

configured to external protocol like BGP (Border gateway protocol) to another

BGP of other ISP or large organization.

SUBSCRIBER EDGE ROUTER:

This type of router belongs to an end user (enterprise) organization. It’s

configured to broadcast external BGP to its provider’s .

INTER-PROVIDER BORDERS ROUTER:This type of router is for Interconnecting ISPs, this is a BGP speaking router

that maintains BGP sessions with other BGP speaking routers in other providers.


Core RouterA router that resides within the middle or backbone of the LAN network rather

than at its periphery. In some instances, a core router provides a step down back

bone, interconnecting the distribution routers from multiple building of a

campus (LAN), or Large enterprise Location (WAN). They tend to be optimized

for a high bandwidth. A core router is a router that forwards packets to

computer hosts within a network but not between networks). A core router is

sometimes contrasted with an edge router , which routes packets between self-

contained network and other outside networks along a network backbone.

Advantage and Disadvantage of Routers

Advantage:

Easily Shared Internet

One of the biggest reasons for using a router is to connect multiple users to the Internet. Connecting to the Internet requires a publicly-unique IP address. As such, Internet providers typically only offer a single IP address or charge fees for large amounts of publicly routable addresses. The solution is to add a router


with network address translation enabled. Connecting to the Internet through a router with NAT allows the router to use the single public IP address and a series of UDP ports to share the connection. Without NAT, connecting a large organization’s computers to the Internet becomes virtually impossible .

Security and Adaptability

Connecting an Internet modem directly to a PC exposes that PC to a host of security issues. Furthermore, expanding a direct-connection network becomes complicated without the addition of switches or a router and communicating between the individual PCs becomes difficult. Using a router as an intermediary between the “outside” network of the Internet and the “inside” network of your organization provides a scalable environment that is also, to a degree, easier to secure. A router is not a replacement for a firewall or anti-malware measures, but it’s an important first step towards a largely secure network environment.

Disadvantage:

Complicated Setup

The aforementioned router requires NAT to be set up. In addition, each computer must be assigned a private IP address that is typically organized by a DHCP server. This is required for the simplest connections. Connecting to additional IP-based networks adds additional complication in the form of routing tables -- a table that describes the best route for reaching a desired network. If IP telephony or video services are to be running on the IP network, you’ll also need to consider quality of service configurations. helps prioritize one type of traffic, such as voice, over others when bandwidth is limited. As additional services are added, more configuration becomes required of the router

Data OverheadUnlike a point-to-point “layer 2” link, routers add additional IP-based headers. These headers include information such as source and destination addresses, UDP information and checksums. These headers are attached to every payload of data. Large pieces of data are typically broken into thousands of smaller headers, making this header data consume a percentage of the total available bandwidth.

Report on Router

Technology

Transcript of Report on Router