Routing protocol algorithm
route to forward the traffic to the destination. An
Algorithm is commonly used to determine the best
algorithm used by the particular routing protocol is responsible for maintaining the routing table. Different routing protocol uses different algorithm and process to add a route in a routing table, send updates to remote router and for path determination dicision.The algorithm defines the following process-
algorithm used by the particular routing protocol is responsible for maintaining the routing table. Different routing protocol uses different algorithm and process to add a route in a routing table, send updates to remote router and for path determination dicision.The algorithm defines the following process-
1. It defines the mechanism for sending and receiving the routing information.
2. It defines the mechanism for calculating the best path and adding routes in the routing table.
3. It defines the mechanism for detecting to topology changes.
Characteristic of distance vector routing protocol-
1. Convergence time-it defines how quickly the
routers in the network topology share routing information. The faster
the convergence time, the most preferable the protocol. Some times
routing loops occur when inconsistent routing table is not updated
because of slow convergence in a changing network.
2. Scalability –it defines how a large network can become based on the routing protocol that is deployed.
3. Classful and classless-classless routing protocol
includes the subnet mask in the routing updates. This is support the
use of VLSM (Variable Length Subnet Mask) and route
summarization.classful routing protocol do not use subnet mask in the
routing updates.
4.resources-This include the requirement of routing
protocol such as, memory space,CPU utilization etc.Some resources
require the more powerful hardware to support the routing protocol
operation in addition to the packet forwarding process.
5. Implementation and maintenance-it describes the
knowledge that is required for a network administrator to implement and
maintain the network based on the routing protocol.
Advantages of distance vector routing protocol-
1. It is simple, easy to maintainance.The knowledge require to configure the protocol is not so high
2. Low resources requirement. Distance vector protocol not need large amount of memory to store the information.
3. Distance vector protocol do nor require high level of bandwidth to send routing updates.
Disadvantages of distance vector routing protocol-
1. It has slow convergence. Even some advances
technique are used, like trigger updates but the overall convergence is
slower compare to link state routing protocol.
2. Slow convergence limits the size of the network because larger networks require more time to send routing information.
3.in distance vector routing protocol routing loops
can occur when inconsistent routing table are not updated because of
slow convergence at the time when network changes.
table by configuring the static routes or configuring
The router adds the remoter network to the routing the dynamic route. When the
router learn about the remoter network and the interface through which
the packet send to the remote network, it adds the information of that
router in the routing rable.A static route include the network address
and subnet mask of the remote network with the ip address of the next
hop router or the exit interface. Static router is denoted as S in the
routing table.
When to use the static routing in the router to reach the destination-
1. When a network consist of only few routers so that the network administrator manually configure all the remote router and set up interfaces
2. When the network is connected to the internet through the single IP.In this point there is no use of dynamic routing protocol because ISP only one exit point to the internet.
3. When the large network is configured into hub and spoke topology because each location only has one path to a given destination through the main network.
In the static routing when there is any change or the network failure occurs between two hosts, this change is not route through the network as in dynamic routing protocol. It means after the troubleshooting of the network packet can route.
Static routing command-
Static routes are commonly used when routing from a network to a stub network stub network is a network accessed by a single route. The command is-
Router (config) # ip route (destination network id) (mask of destination network) (next-hop address or exit interface)
This is an advantage to using exit interface in the static routes. The routing table process only has to perform a single lookup to find the exit interface to resolve a next- hop address. For static routes with outbound point to point serial network, it is best to configure the static routes with only the exit interface. For point to point serial interfaces, the next hop address in the routing table is never used by the packet delivery procedure, so it is not needed. For the static route with outbound Ethernet network, it is best to configure the static routes with the both next-hop address and exit interface.
emote networks. A routing table contain network
A routing table is a data file in a RAM that is used to store
route information about directly connected and remote networks. A
routing table contain network or next hop information that tell a router
that a particular router representing the ‘next-hop’ on the way to the
final destination. A routing table is viewed as a table format that
determined where the data packet to be directed in the network to reach
the destination network.
A routing table contains the necessary information to forward the packet along the best path and each packet contains the information about its source and the destination. Routing table just like a database which keep the track of paths.
When router receives any packet, it examines the packet and matches it to the routing table to providing the best match for its destination. The table provides the instruction to the router for sending the packet to the next hop on its route across the network. A routing table contains different types of entries-Network route –it is a route to a specific network id in the internetwork.Host route-it is a route to a specific internetwork address that is network ID and Host ID and the Default route-it is a route that is configure when no match is found for the destination in the routing table.
A routing table includes the following information-
-Destination IP address
-IP address to which the packet is forward
-Outgoing network interface of the router
-Metric used to determine which path is most preferable when there are multiple paths to the destination network.
-Routes-network routes, host route and default route
A remote network is a network that is directly connected to the router. In other words a remote network is a network that can only be reached by sending the packet to another router. Remote network are added to the routing table using a dynamic routing protocol or by configuring the static routes. Dynamic routes are routes to remote network that are learned automatically by the router using the dynamic routing protocol. Static routes are the routes to network that a network administrator manually configured on the router.
forward the packets and is the least–cost route to
A successor is neighbor router that is used to the destination network.Feasible
distance is the lowest calculated metric to the destination.This is
listed in the routing table entry.
In EIGRP,DUAL converges quickly after the topology changes and uses the backup path to other router known as feasible successor.A feasible successor is a neighbor which provides the loop free path to the same network as the successor.
The successor,feasible distance and feasible successor placed with their reported distance in its EIGRP topology table and this can be display by this command-
Router # show ip eigrp topology
Disabling automatic summarization
EIGRP automatic summarizes major network boundaries using the command auto-summary.In EIGRP,DUAL takes all the neighbor adjacencies and reestablishes them and all EIGRP neighbor will immediately send out new updates that will not automatically summarized.
Manual summarization
EIGRP can be configured to summarize the routes,whether the automatic summarization is enable or not.EIGRP is classless routing protocol and include the subnet mask in the routing updates,manual summarization include supernet routes that is a aggregation of multiple classful network address.
To calculate the EIGRP summary route
To calculate the summary route for IGRP use the following steps-
Write all the network that is to be summarized in the binary form.
For the subnet mask,start from the left most bits.
Selects the match bits from left to right.
Stop at the column where the bits don’t match.
Count the number of left most matching bits.This number is the network bits or the subnet mask.
To find the network address for the summarization after the matching bits add all bits 0 to the end of 32 bit.
For example
192.168.1.0 – 11000000.10101000.00000001.00000000
192.168.2.0 – 11000000.10101000.00000010.00000000
192.168.3.0 – 11000000.10101000.00000011.00000000
The first 22 bits are matching so the subnet mask will be /22 that is
255.255.252.0
and the device are not pinging to each other
When in end – to –end connectivity is in problem . When there is a change in the network
connectivity, then administrator should find the way to resolve the
problem. There are some commands that help a lot in troubleshooting-
‘Ping’ command
Ping is stood ‘Packet internet Gropher’.It is a command by which we can check whether the particular host is reachable or not in the network. This command is work by sending the ICMP echo request and listing echo request reply. We use ping command to check the connectivity of my system to another in the network and if we can’t a site and the other entire site are ping, so it’s not a problem of my network. It is problem of that particular site only. If we can’t ping any site or system then the problem is in our network connection. So troubleshooting is must in this case to resolve the problem.
We can use ping command on the MSDOS window and then type ping followed by the domain name or IP address of the computer, we want to ping. We can get a list of the available options for the windows ping command with “ping – ?”
‘Traceroute’ command
The trace route command finds the break in the path when packet moves from source to the destination. The traceroute command traces the network path of the routers when the packet sends from sender to receiver. On the window computer, we can run traceroute in a MSDOS or command window by typing ‘tracert’followed by domain name.
By using the ping and traceroute command, we get the router- trip time. This is the time request to send the echo packet and get the echo reply. This is the useful for a idea of the delay of the link.
‘Show ip route’ command
The show IP route command is used to display the routing table of the router. Initially the routing table is empty if there is no interfaces have been configured. It shows directly connected networks, static route, dynamic route, routing protocols etc.
‘Show ip int brief’ command
This command show the interfaces information briefly-like all the interfaces is configured properly with ip address and the status whether it is up or down.
The Static Routing
table by configuring the static routes or configuring
When to use the static routing in the router to reach the destination-
1. When a network consist of only few routers so that the network administrator manually configure all the remote router and set up interfaces
2. When the network is connected to the internet through the single IP.In this point there is no use of dynamic routing protocol because ISP only one exit point to the internet.
3. When the large network is configured into hub and spoke topology because each location only has one path to a given destination through the main network.
In the static routing when there is any change or the network failure occurs between two hosts, this change is not route through the network as in dynamic routing protocol. It means after the troubleshooting of the network packet can route.
Static routing command-
Static routes are commonly used when routing from a network to a stub network stub network is a network accessed by a single route. The command is-
Router (config) # ip route (destination network id) (mask of destination network) (next-hop address or exit interface)
This is an advantage to using exit interface in the static routes. The routing table process only has to perform a single lookup to find the exit interface to resolve a next- hop address. For static routes with outbound point to point serial network, it is best to configure the static routes with only the exit interface. For point to point serial interfaces, the next hop address in the routing table is never used by the packet delivery procedure, so it is not needed. For the static route with outbound Ethernet network, it is best to configure the static routes with the both next-hop address and exit interface.
The Routing Table
emote networks. A routing table contain network
A routing table contains the necessary information to forward the packet along the best path and each packet contains the information about its source and the destination. Routing table just like a database which keep the track of paths.
When router receives any packet, it examines the packet and matches it to the routing table to providing the best match for its destination. The table provides the instruction to the router for sending the packet to the next hop on its route across the network. A routing table contains different types of entries-Network route –it is a route to a specific network id in the internetwork.Host route-it is a route to a specific internetwork address that is network ID and Host ID and the Default route-it is a route that is configure when no match is found for the destination in the routing table.
A routing table includes the following information-
-Destination IP address
-IP address to which the packet is forward
-Outgoing network interface of the router
-Metric used to determine which path is most preferable when there are multiple paths to the destination network.
-Routes-network routes, host route and default route
A remote network is a network that is directly connected to the router. In other words a remote network is a network that can only be reached by sending the packet to another router. Remote network are added to the routing table using a dynamic routing protocol or by configuring the static routes. Dynamic routes are routes to remote network that are learned automatically by the router using the dynamic routing protocol. Static routes are the routes to network that a network administrator manually configured on the router.
Successor and Feasible successor
forward the packets and is the least–cost route to
In EIGRP,DUAL converges quickly after the topology changes and uses the backup path to other router known as feasible successor.A feasible successor is a neighbor which provides the loop free path to the same network as the successor.
The successor,feasible distance and feasible successor placed with their reported distance in its EIGRP topology table and this can be display by this command-
Router # show ip eigrp topology
Disabling automatic summarization
EIGRP automatic summarizes major network boundaries using the command auto-summary.In EIGRP,DUAL takes all the neighbor adjacencies and reestablishes them and all EIGRP neighbor will immediately send out new updates that will not automatically summarized.
Manual summarization
EIGRP can be configured to summarize the routes,whether the automatic summarization is enable or not.EIGRP is classless routing protocol and include the subnet mask in the routing updates,manual summarization include supernet routes that is a aggregation of multiple classful network address.
To calculate the EIGRP summary route
To calculate the summary route for IGRP use the following steps-
Write all the network that is to be summarized in the binary form.
For the subnet mask,start from the left most bits.
Selects the match bits from left to right.
Stop at the column where the bits don’t match.
Count the number of left most matching bits.This number is the network bits or the subnet mask.
To find the network address for the summarization after the matching bits add all bits 0 to the end of 32 bit.
For example
192.168.1.0 – 11000000.10101000.00000001.00000000
192.168.2.0 – 11000000.10101000.00000010.00000000
192.168.3.0 – 11000000.10101000.00000011.00000000
The first 22 bits are matching so the subnet mask will be /22 that is
255.255.252.0
To troubleshooting a missing route
and the device are not pinging to each other
‘Ping’ command
Ping is stood ‘Packet internet Gropher’.It is a command by which we can check whether the particular host is reachable or not in the network. This command is work by sending the ICMP echo request and listing echo request reply. We use ping command to check the connectivity of my system to another in the network and if we can’t a site and the other entire site are ping, so it’s not a problem of my network. It is problem of that particular site only. If we can’t ping any site or system then the problem is in our network connection. So troubleshooting is must in this case to resolve the problem.
We can use ping command on the MSDOS window and then type ping followed by the domain name or IP address of the computer, we want to ping. We can get a list of the available options for the windows ping command with “ping – ?”
‘Traceroute’ command
The trace route command finds the break in the path when packet moves from source to the destination. The traceroute command traces the network path of the routers when the packet sends from sender to receiver. On the window computer, we can run traceroute in a MSDOS or command window by typing ‘tracert’followed by domain name.
By using the ping and traceroute command, we get the router- trip time. This is the time request to send the echo packet and get the echo reply. This is the useful for a idea of the delay of the link.
‘Show ip route’ command
The show IP route command is used to display the routing table of the router. Initially the routing table is empty if there is no interfaces have been configured. It shows directly connected networks, static route, dynamic route, routing protocols etc.
‘Show ip int brief’ command
This command show the interfaces information briefly-like all the interfaces is configured properly with ip address and the status whether it is up or down.
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