Routing

Static Routes and Default Routes

What is a Static Route

A static route is a route that is created manually by a network administrator. Static routes are typically used in smaller networks. In static routing, the Router’s routing table entries are populated manually by a network administrator.

The opposite of a static route is a dynamic route. In dynamic routing, the the routing table entries are populated with the help of routing protocols.

The major advantages of static routing are reduced routing protocol router overhead and reduced routing protocol network traffic. The major disadvantages of static routing are network changes require manual reconfiguration in routers and network outages cannot be automatically routed around. Also it is difficult to configure static routing in a complex network.

What is a Default Route

A Default Route (also known as the gateway of last resort) is a special type of static route. Where a static route specifies a path a router should use to reach a specific destination, a default route specifies a path the router should use if it doesn’t know how to reach the destination.

Default Route is the network route used by a router when there is no other known route exists for a given IP datagram’s destination address. All the IP datagrams with unknown destination address are sent to the default route.

Posted By – RamCruiseWalker

Introducion

Administrative Distance

Administrative Distance (AD) is a value that routers use in order to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative Distance counts the reliability of a routing protocol. Administrative Distance (AD) is a numeric value which can range from 0 to 255. A smaller Administrative Distance (AD) is more trusted by a router, therefore the best Administrative Distance (AD) being 0 and the worst, 255.

Administrative Distance (AD) Route Type
0 Connected interface
0 or 1 Static Route
90 Internal EIGRP Route (within the same Autonomous System (AS))
100 IGRP Route
110 OSPF Route
115 IS-IS
120 RIP Route
255 Unknown Route

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Protocol, Routing

Dynamic Routing Protocol

Overview

In the previous chapter, we looked at static routing. We saw how the router finds the best path to a network. We configured static routes and traffic was able to flow between two points.

In this chapter, we will give an overview of dynamic routing protocols. We will define them and learn how they are different from static routes. We will discuss their advantages over static routes, learn the different categories of dynamic routing protocols as well as classless and classful nature. We will also talk about the administrative distance and the metric.

Consider the network diagram shown below.

The administrative overhead that would be needed to make communication between all these devices would be considerable. All the static routes would have to be configured.

Wouldn’t it be much easier, for the network administrator to just “Teach” the routers how to get from one point to another? The solution to this problem would be dynamic routing protocols.

Dynamic routing protocols are a solution that is used in large networks so as to reduce the complexity in configuration that would be occasioned by having to configure static routes. In most networks you will see a mix of both dynamic and static routes.

Definition of dynamic routing protocols

Routing protocols are used to enable the routers exchange routing information, they allow routers to learn about remotely connected networks dynamically. This information is then added to their routing tables as a basis for forwarding packets.

Classification

Dynamic routing protocols can be classified in several ways.

  • Interior and exterior gateway routing protocols,
  • Distance vector, path vector and link state routing protocols,
  • Classful and classless.

The table below shows the various categories of dynamic routing protocols and the ones highlighted inred
will be the focus of this course. Others will be discussed at the CCNP and the CCIE level.

In this course, we will look at EIGRP, OSPFv2 and OSPFv3. These topics will be crucial in passing both your ICND1 and ICND 2 exam, and the CCNA composite exams.

The table below shows more information on the routing protocols to be covered in this course.

Acronym Full name standard year RFC
EIGRP Enhanced Interior Gateway Routing Protocol CISCO 1992 NULL
OSPFv2 Open Shortest Path First version 2 Open 1991 5709
OSPFv3 Open Shortest Path First version 3 Open 1999 5838

Although you may not be examined on the information above directly, both exams will have questions that require knowledge of this information.

Operation of routing protocols

Now that we have an overview of routing protocols, we need to understand how they work.

Routing protocols are comprised of processes, messages and algorithms that are used by routers to learn about remotely connected networks from routers that have been configured with the same routing protocols, the routes that have been learnt are added to the routing table and used as a basis for forwarding packets.

  • Routing protocols function by:
  • Discovering remote networks
  • Maintaining current routing information
  • Path determination

The routing protocol is made up of these components.

  1. Data structures – this is information about remote networks. It is usually stored in the RAM and may be comprised of tables such as neighbor tables and topology tables.
  2. Algorithm – this is the sequential list of steps that the routing takes when determining the best path to a particular network.
  3. Routing protocol messages – these are messages that are used to maintain updated routing information. Examples include; hello messages, update messages among others.

The way routing protocols operate may differ depending on the routing protocol, however, there are certain characteristics inherent in every routing protocol.

  • Exchange of information on interfaces to discover neighboring routers
  • Exchange of routes that have been advertised
  • Running of the algorithm so as to determine the best path
  • Adding of best paths to the routing table
  • Detection of topology changes and making the necessary changes

These are the general steps routers will take. However, the processes differ with each routing protocol and will be discussed at a later stage.

Advantages and disadvantages

Now that we have seen the dynamic routing protocols to be covered in this course, we need to know the advantages and disadvantages of using dynamic routing protocols. We also need to compare them to static routes.

Advantages

  • Exchange of routing information when there is a topology change is dynamic.
  • Less administrative overhead as compared to static routes which have to be manually configured
  • Less error prone than static routing which.
  • Scalability, since there is less administrative overhead than static routes.

Disadvantages

  • Require more expertise by the administrator, they are not as simple to configure as static routes.
  • They use more of the routers resources; such as CPU and RAM.

Egp vs igp

As mentioned earlier, routing protocols fall into two main categories which are;

  • EGP – Exterior Gateway Protocols
  • IGP – Interior Gateway Protocols

This categorization, is based on the Autonomous Systems.

Autonomous systems also known as routing domains; are collections of routers under the same administration. This may mean the routers that are owned by one company.

For example, company XYZ, could have 1 branch connected to the headquarters through a leased line. The networks owned and managed by XYZ would be one autonomous system, while the leased line and interconnections between the branch office and the headquarters which are controlled by the ISP would be another autonomous system. This is shown in the exhibit below.

The networks controlled by XYZ are labelled as AS 100 while AS 650 represents the ISP.

Interior Gateway Protocols (IGP) are used for intra-autonomous system routing – routing inside an autonomous system.

Exterior Gateway Protocols (EGP) are used for inter-autonomous system routing – routing between autonomous systems.

In this scenario for example, routing between XYZ headquarters and the branch office would use and IGP, whilst routing between company XYZ and the ISP would use an EGP.

Distance vector routing protocols vs. link state routing protocols

Interior Gateway Protocols (IGPs) can be classified as two types:

  • Distance vector routing protocols
  • Link-state routing protocols

Distance vector means that routes are advertised as vectors of distance and direction. If we take an example of a tourist getting directions, distance vector protocols would be where the tourist would only use road signs to get to where they are going. They do not know the exact landscape and possible blocks, they only know of the next point towards their destination.

Distance vector protocols work best in situations where:

  • The network is simple and flat and does not require a special hierarchical design.
  • The administrators do not have enough knowledge to configure and troubleshoot link-state protocols.
  • Specific types of networks, such as hub-and-spoke networks, are being implemented.
  • Worst-case convergence times in a network are not a concern

On the other hand, if the tourist had an entire map of the desired destination, with details of different paths to where they were going, they would be using a link-state routing protocol.

Link state routing protocols usually have a complete view of the topology. They usually know of the best paths as well as backup paths to networks. Link state protocols use the shortest-path first algorithm to find the best path to a network.

Link-state protocols work best in situations where:

  • The network design is hierarchical, usually occurring in large networks.
  • The administrators have a good knowledge of the implemented link-state routing protocol.
  • Fast convergence of the network is crucial.

Classful and classless

Classful Routing Protocols

Classful routing protocols don’t include the subnet mask in their routing updates. This is because they were designed prior to the introduction of CIDR and VLSM. RIPv1 is an example of such protocols.

Since they do not include the subnet mask in their routing updates, they cannot work where the networks have been subnetted.

Classless routing protocols

Classless routing protocols include the subnet mask with the network address in routing updates.

In this course, we will focus on the classless routing protocols since the use of classful routing protocols is outdated and no longer used in most modern networks.

Administrative distance and metric

Metric

Suppose a router has more than 1 destination to a network, how would it determine the best path to that network?

The metric, is the mechanism used by the routing protocol to assign costs to reach remote networks. In the tourist example, this may be the amount of fuel the tourist has to use to get to their destination. The metric is used to determine the best path to a network when there are multiple paths.

The table below shows the various metrics used by routing protocols which will be covered in this course.

Routing protocol Metric Description
RIPv1 Hop count The number of routers between the source and destination network.
RIPv2 Hop count The number of routers between the source and destination network.
EIGRP Composite metric A combination of several values used to determine the best path. The composite metric will be discussed in the chapter on EIGRP.
OSPFv2 Cost The bandwith or cost configured from the router to the destination network
OSPFv3 Cost The bandwith or cost configured from the router to the destination network

Understanding the different costs types will be crucial in your final exam.

Administrative distance

What if we had configured several routing protocols on one router, how would the router determine the best path to the desired network?

The administrative distance is the way routers use to give preference to routing sources. For example if a router learns of the same route via EIGRP and RIP, it will prefer the route it learnt via EIGRP.

All routes in the routing table are prioritized. With the best and most preferred paths being the directly connected routes. The AD is the trustworthiness of a route.

The AD is usually a value from 0 to 255, the lower the value the better the routing source, a route with an administrative distance of 255 will never be trusted.

If we use the tourist example, the administrative distance would be the trust placed on each means of transport, for example an airline would be more trusted over walking.

The table below shows the various administrative distances for the routing protocols which will be covered in this course.

Routing protocol Administrative distance
RIP 120
OSPF 110
EIGRP 90
Static routes 1

Summary

In this chapter, we have learnt about dynamic routing protocols. We defined and classified the various routing protocols. We explained how they work as well as their advantages and disadvantages. We also looked at the various classifications of routing protocols such as; EGP and IGP and distance vector and link state routing protocols. We also looked at classful and classless routing protocols as well as explained what the metric and administrative distance mean.

NOTE: The concepts learnt in this chapter are crucial in understanding routing. These concepts are usually examined in both ICND 1 and ICND 2 as well as the CCNA composite exam. These concepts will also be useful at the CCNP and CCIE levels.

In the next chapter, we will look at the first routing of this course which is EIGRP.

Posted By – RamCruiseWalker

Protocol, Routing

Static Routing Protocol

Overview

Welcome to the world of routing. In the next few chapters, we will look at how packets find their way in networks through routers. In this chapter, we will learn static routing.

Routers in our networks discover remote networks in one of two ways;

  1. Statically configured routes
  2. Dynamic routing protocols

We will learn various concepts on static routes such as how to configure static routes, how the routing table bases its decisions, routing interfaces among other concepts.

Introduction

as you may already know, the work of the router is to forward packets from the source device to the destination device. In between there may be several routers. The router uses a database known as the routing table to forward these packets.

In previous chapters, we connected a router to computer and verified communication by using ping. However, refer to the topology shown in the exhibit below.

 

The network above shows a small network consisting of 3 routers and 2 hosts. As discussed earlier, each connection to a router should have its own network segment and this is shown in the diagram.

The network administrator also configured R1’s and R3’s serial interfaces as the DCE and all other configurations are correct.

In this scenario, R1 can ping HOST A, R1 can ping R2 s0/0/0 interface but not interface s0/0/1.

R3 can ping HOST B, R3 can ping R2’s s0/0/1 interface ONLY. HOST A and HOST B cannot communicate. As shown in the exhibit below.

In this chapter, we will explain the reasons as to why these two computers cannot communicate and resolve this problem.

KEEP THIS TOPOLOGY IN MIND AS IT WILL BE USED THROUGHOUT THIS CHAPTER.

Directly connected networks

The routing table is the database that contains information about various networks, we have said that these remote networks may either be learnt through routing protocols or manually configured routes.

The output of the “show ip route” command on a router, shows the routes that a particular router can reach. By default, a router will only know of directly connected routes.

Directly connected routes in our scenario, from R1’s perspective are the network connected to HOST A and the network between R1 and R2.

Since no other configuration has been made on these routers, R2 and R3, should only have directly connected routes.

The directly connected networks are the only networks that can be reached by a particular router. In our scenario, this means that;

  • Host A can ping R1
  • R1 can ping R2’s s0/0/0 interface but not interface s0/0/1
  • R2 can ping R1’s s0/0/0 interface but not interface fa0/0 or HOST A
  • R2 can ping R3’s s0/0/0 interface but not interface fa0/0 or HOST B
  • R3 can ping R2’s s0/0/1 interface but not interface s0/0/0
  • HOST B can ping R3.
  • Neither hosts can ping each other
  • R1 and R3 cannot ping each other.

The figure shown below shows all the directly connected networks.

Static routing

Static routes are one way we can communicate to remote networks. In production networks, static routes are mainly configured when routing from a particular network to a stub network.

stub networks are networks that can only be accessed through one point or one interface.

In the above scenario, the 192.168.1.0/24 and 192.168.4.0/24 networks are stub networks. This means that for hosts in these network segments only have one way to communicate with other hosts, which is R1 and R3 for the 192.168.1.0/24 and 192.168.4.0/24 networks respectively.

Understanding stub networks is crucial in understanding static routing.

The command needed to configure a static route is shown below.

Router(config)# ip route (network-address) (subnet-mask) (next-hop ip address/ exit interface)

The table below explains the meaning of each of the parameters in the ip route command as well as an example of the command which would be used on R1 to configure a static route to R3’s LAN network (192.168.4.0/24).

Parameter Meaning example
Ip route State that the route being configured is a static route Ip route
Network-address The network address of the destination network. This is the network I am trying to reach. 192.168.4.0
Subnet-mask The network address of the destination network that I am trying to reach 255.255.255.0
Next hop ip address This is the ip address of the router that is connecting me to the desired network 192.168.2.4
Exit interface This is the exit point interface on my router that connects to the router that will take me to the desired network s0/0/0

 

Refer to the exhibit. Therefore to configure a static route on R1 for network 192.168.4.0/24, the command to be issued on R1 is:

R1(config)# ip route 192.168.3.0 255.255.255.0 192.168.2.4

R1(config)# ip route 192.168.4.0 255.255.255.0 192.168.2.4

OR

R1(config)# ip route 192.168.3.0 255.255.255.0 s0/0/0

R1(config)# ip route 192.168.4.0 255.255.255.0 s0/0/0

NOTE: When configuring static routes
you should only use either the exit interface or the next hop ip address and not both. This will be explained later.

EXAMINE THE ROUTING TABLE ON R1:

1

Highlighted in
red
at the bottom of the show ip route output on R1, is the static route that we just added. The “S” at the beginning means that the routing table got this route as a result of a static route configuration.

In the braces, “1”, is the administrative distance for static routes, and “0” is the metric.

From this we can assume that pings from HOST A to HOST B should work. Right?

Let’s try a ping from HOST A TO HOST B and see what happens.

2

As you can see from the exhibit above, all four pings to HOST B are shown as request timed out. Further, highlighted in red
at the bottom, no packets were received by HOST B. this means that they could not communicate.

In the next section, we will explore why the two hosts could not communicate yet R1 was correctly configured with a static route.

Routing table principles

There are three routing table principles that dictate how routers communicate.

Principle 1:

routers forward packets based on information contained in their routing tables ONLY.”

R1 has 2 routes 192.168.3.0/24 which is the connection between R2 and R3, and 192.168.4.0/24, which is the network on which HOST B is located. Therefore, based on the first principle, R1 will make its forwarding decisions based on this information only. It will not consult R2 or R3.Nor does it know whether or not those routers have routes to other networks. As a network administrator, it is your responsibility to make sure that all the routers in a network know about remote networks.

Principle 2:

” Routing information on one router does not mean that other routers in the domain have the same information.”

R1 doesn’t know about the information in R2’s routing table. The same can be said of R2 and R3. Therefore, the fact that R1 has a path to the networks connected to R2 and R3 does not mean that R2 and R3 have the same information.

For example, can reach the network 192.168.4.0/24 on R3 through R2. R1 does not know whether R2 can reach the network connected to R3. Therefore, we need to configure routes from R2 to the LAN connected to R3.

Using Principle 2, we still need to configure the proper routing on the other routers (R2 and R3) to make sure that they have routes to these three networks.

Principle 3:


“Routes on a router to a remote network do not mean that the remote router has return paths.”

This principle means that when a route is configured on one router, the remote router must be configured with a return route. In our networks, most of the communication is bidirectional, this means that for every message we send, a reply is expected.

If we use the analogy of the post office, it would be like sending a letter without a return address. The recipient cannot reply to a letter without a return address, and the postman would not know where to send the letter.

In our scenario, this means that, when we configure a route to network 192.168.4.0/24 on R1, we need to configure a route on the remote routers that leads to the LANs connected to R1.

Using Principle 3 as guidance, we will configure proper static routes on the other routers to make sure they have routes back to the 192.16.1.0/24 network.

Applying the principles:

In this scenario, we need to apply all the three principles on all the routers so that the static routes can work.

Principle 1

R1 knows how to get to network 192.168.3.0/24, and network 192.168.4.0/24, however, R2 and R3 do not know how to get there. Therefore, we need to configure a static route on R2 so that it can know how to get to 192.168.4.0/24.

Principle 2

We configured a static route on R1, however, this does not mean that R2 knows a path to 192.168.4.0/24 network. Therefore this router needs to know about that network.

Principle 3

Even though R1 and R2 have a route to network 192.168.4.0, a ping would still fail because both R2 and R3 would not know how to get to R1. Therefore, we need to configure a route that gets back to network 192.168.1.0/24 on R1.in this case we are using the next-hop ip address on both R2 and R3.

From this. We can now make the necessary configurations on all the routers to make communication between HOST A and HOST B possible.

On router R2:

R2(config)# ip route 192.168.1.0 255.255.255.0 192.168.2.3

R2(config)# ip route 192.168.4.0 255.255.255.0 192.168.3.3

On router R3:

R3(config)# ip route 192.168.1.0 255.255.255.0 192.168.3.4

R3(config)# ip route 192.168.4.0 255.255.255.0 192.168.3.4

When all the configurations have been made on all the three routers, communication between HOST A and HOST B should be possible. The figure below shows the routing tables of all the three routers, the static routes have been highlighted in red.

R1:

3

R2:

4

R3:

5

As a result of this output. We should be able to ping from HOST A to HOST B. the output below shows the results of the ping from HOST A to HOST B.

6

The output shows that there are replies coming from HOST B which has the ip address 192.168.4.2, the highlighted section in red shows that 4 packets were sent and all 4 were received by HOST B, with 0% loss.

Therefore, we have successfully configured static routing on the routers.

Resolving the next- hop ip address

Suppose we configured R2 with the next-hop ip address not an exit interface, how would the router know which interface to send the packets through?

Refer to the output of the show ip route command on R2, below.

7

When the router wants to send a packet to the 192.168.1.0 network, it will look at the routing table.

There is a route to that network via 192.168.2.3. Then the router checks to see whether it has an interface that to the 192.168.2.3 network. In this scenario, that would be the network highlighted in blue. The exit interface is serial 0/0/0.

Routes that only have the next-hop ip address and no exit interfaces, must have resolve the next hop ip address using a route on their routing table that connects to the remote network.

In most cases, the route that the next hop is resolved to is usually a directly connected network.

As such, this is usually an issue, since the router has to process a packet twice before it can determine where to forward it. This is known as a recursive lookup.

It is recommended that static routes have an exit interface as opposed to the next hop ip address.

Summary and default routes

Suppose a router has more than 1 LAN connected to it. It would be more practical to use an address that covers all the LANS, and configure 1 static route. Take this scenario, R1 has 5 LANs connected to it;

  • 192.168.1.0/24
  • 192.168.2.0/24
  • 192.168.3.0/24
  • 192.168.4.0/24
  • 192.168.5.0/24

Summarizing these routes is shown in the table below.

8

The first 2 octets and the first 5 bits from the left, in the third octet.

Therefore the new summary network address and subnet mask for the 5 networks will be:192.168.0.0/21 with the subnet mask as 255.255.248.0.

When configuring a static route to the summary network out serial0/0/0 on R2, the command would be;

R2(config)# ip route 192.168.0.0 255.255.248.0 s0/0/0

Refer to the exhibit shown below. Suppose HOST A wants to send an email to a friend or wants to view a website on the internet, how would the router know where to send the packets?

The internet has many ip addresses, and configuring one static route to a specific network would not work. Therefore, a default route is needed.

A default static route is a route that will match all packets. Default static routes are used:

When no other routes in the routing table match the packet’s destination IP address. In other words, when a more specific match does not exist. A common use is when connecting a company’s edge router to the ISP network.

When a router has only one other router to which it is connected. This condition is known as a stub router.

The syntax for configuring a static default route is:

Router(config)# ip route 0.0.0.0 0.0.0.0 [next-hop ip address/ exit interface]

A route to this network would tell the router to forward any packet for which it does not have a route to the indicated next-hop ip address or exit interface.

In this scenario, to configure a default static route, the command sequence on R1 would be.

R1(config)# ip route 0.0.0.0 0.0.0.0 12.145.3.2

Or

R1(config)# ip route 0.0.0.0 0.0.0.0 s0/0/0

Summary

In this chapter, we have learnt how a router finds a path to a remote network, we have configured static routes using the principles of the routing table, learnt about the recursive lookup, as well as configured summary routes and default static routes.

In the next chapter, we will get into the world of dynamic routing protocols.

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Protocol

Difference between Interior Gateway Protocol (IGP) and Exterior Gateway Protocol (EGP)

Interior Gateway Protocol (IGP) is a Routing Protocol which is used to find network path information within anAutonomous System.

Known Interior Gateway Protocol (IGP) Routing Protocols are Routing Information Protocol (RIP), Interior Gateway Routing Protocol (IGRP), Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS)

Exterior Gateway Protocol (EGP) is a Routing Protocol which is used to find network path information between different Autonomous Systems. Exterior Gateway Protocol (EGP) is commonly used in the Internet to exchange routing table information. There is only one Exterior Gateway Protocol (EGP) exists now and it is Border Gateway Protocol (BGP).

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Introducion

Autonomous System | Autonomous System Number

                        An Autonomous System (AS) is a group of networks under a single administrative control which could be an Internet Service Provider (ISP) or a large Enterprise Organization. An Interior Gateway Protocol (IGP) refers to a routing protocol that handles routing within a single autonomous system. IGPs include RIP, IGRP, EIGRP, and OSPF. An Exterior Gateway Protocol (EGP) handles routing between different Autonomous Systems (AS). Border Gateway Protocol (BGP) is an EGP. BGP is used to route traffic across the Internet backbone between different Autonomous Systems.

When BGP (Border Gateway Protocol) was at development and standardization stage, a 16-bit binary number was used as the Autonomous System Number (ASN) to identify the Autonomous Systems. 16-bit Autonomous System Number (ASN) is also known as 2-Octet Autonomous System Number (ASN). By using a 16 bit binary number, we can represent (2 16) numbers, which is equal to 65536 in decimals.

The Autonomous System Number (ASN) value 0 is reserved, and the largest ASN value 65,535, is also reserved. The values, from 1 to 64,511, are available for use in Internet routing, and the values 64,512 to 65,534 is designated for private use.

Available 16-bit (2-Octet) Autonomous System Numbers (ASN) were in verge of depletion by middle of 2011. To provide more Autonomous System Numbers (ASN), IETF published RFC 4893 in May 2007, which introduced 32-bit AS numbers. 32-bit Autonomous System Number (ASN) is also known as 4-Octet Autonomous System Number (ASN). 32-bit (4-Octet) AS numbers are represented as either as simple integers, or in the form x.y, where x and y are 16-bit numbers. Numbers of the form 0.y are exactly the previous 16-bit AS numbers.

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Introducion

Difference Between Routable Protocol and Non-Routable Protocol

Routable protocol

A Routable protocol is a network protocol which can carry data from one network and can pass through the router to reach another network and be delivered to a computer in that remote network.

Examples of routable protocols: Internet Protocol (IP -IPv4 and IPv6), IPX, AppleTalk, VINES Internetwork Protocol (VIP), DECnet

Routable Protocol

Non-routable protocols

A non-routable protocol’s data cannot be passed through a router to reach a remote network. This is mainly because of the lack of capability of protocol (almost all non-routable protocols are designed long back which will not fit well in current networks) and the addressing scheme the non-routable protocol is using.

Non-routing protocols reachability limit is its own network and they are designed in such a way to think that all computers they communicate are on the same network as the source computer.

Non Routable Protocol

Examples of non-routable protocols: Local Area Transport Protocol (LAT), NetBios Extended User Interface (NetBEUI).

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Introducion

Router interface naming convention

Cisco Routers different types of interfaces like Serial, Ethernet, Fast Ethernet, Gigabit Ethernet, Tokenring,  FDDI are some of them (A single router may not have all these). The speed of Ethernet, Fast Ethernet and Gigabit Ethernet are different. The speed of Ethernet is 10 Mbps (Megabits per second), Fast Ethernet is 100 Mbps (Megabits per second) and Gigabit Ethernet is 1 Gbps (Gigabits per second)

Most of the latest routers are modular routers. Modular routers are expandable routers by using plug-in components.

The following naming convention is followed for a Cisco Router.

<Interface_Type><Slot_Number/Port_Number>

Slot numbers begin with 0 and port numbers begin with 0. Hence the name of the first interface of a WIC2T (modular card with two smart serial interfaces) is serial0/0 and the name of the second port is serial0/1. The short form of the two interface is s0/0 and s0/1.

Old 2500 series routers are not modular, and they had fixed ports. The interface naming convention of these routers is

<Interface_Type>< Port_Number>

Hence the name of the first Ethernet interface for non-modular router is ethernet0 or e0, and first Serial interface is serial0 or s0.

Introducion

Difference Between Routing Protocols and Routed Protocols

Routed Protocols

A Routed Protocol is a network protocol which can be used to send the user data from one network to another network. Routed Protocol carries user traffic such as e-mails, file transfers, web traffic etc.

Routed protocols use an addressing system (example IP Address) which can address a particular network and a host (a computer, server, network printer etc) inside that network. In other words, the address which is used by a Routed Protocol (Example IP (Internet Protocol)) has a network address part and a host (a computer inside a network) part.

IP (Internet Protocol) is the most widely used Routed Protocol. Internet is using IP (IPv4 or IPv6) as its Routed Protocol. Other Routed protocols are vanishing from network industry.

A Routed Protocol is an integral part of network protocol suit and it is available in every device which is participating in network communication (Example, Routers, Switches, Computers etc).

Routing Protocol

A Routing Protocol learns routes (path) for a Routed Protocol and IP (Internet Protocol), IPX (Internetwork Packet Exchange) and Appletalk are the examples of Routed Protocols.

Routing Protocols are network protocols used to dynamically advertise and learn the networks connected, and to learn the routes (network paths) which are available. Routing protocols running in different routers exchange updates between each other and most efficient routes to a destination. Routing Protocols have capacity to learn about a network when a new network is added and detect when a network is unavailable.

Routing Protocols normally run only in Routers, Layer 3 Swithes, End devices (firewalls) or Network Servers withNetwork Operating Systems. Routing Protocols are not available in a normal computer or a printer.

Examples of Routing Protocols are RIP (Routing Information Protocol) , EIGRP (Enhanced Interior Gateway Routing Protocol) and OSPF (Open Shortest Path First).

Following table lists important Routing Protocols related Routed Protocols.

Routed Protocol Routing Protocols
IP RIP, IGRP, OSPF, EIGRP
IPX RIP, NLSP, EIGRP
Appletalk RMTP, AURP, EIGRP

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Introducion

Difference Between Static Route and Dynamic Route

Routing is the process of selecting paths in a network along which to send network traffic and route is the path to send the network traffic.

There are two ways a router learn a route: static and dynamic. The difference between static route and dynamic route is as below. A static route is a route that is manually configured on the router. Simply we can say a static route is a route that is created manually by a network administrator. The information about the networks that are directly connected to the active router interfaces are added to the routing table initially and they are known as connected routes. The second way that the router can learn static routes are by configuring the routes manually.

Dynamic routes are routes that a router learns by using a routing protocol. Routing protocols will learn about routes from other neighbouring routers running the same routing protocol. Dynamic routing protocols share network numbers a router knows about and how to reach these networks. Through this sharing process, a router can learn about all of the reachable network numbers in the network.

Posted By – RamCruiseWalker