Dynamic Routing - 2 Lectures

Dynamic Routing

You configuring the route and automatic mall all the other route in the same routing table gets the information. Ex”hey, Boston routing router has this IP address and then network router will get the information, NY…. You don’t have to go and configure that.

-you configure using just one router. then all the other routers will learn the routing table.

“The router sends and receives routing messages on the router interfaces.”

Routers have a certain way of communicating with each other in dynamic routing. They talk next to each other and the other one asks “hey, do you have something new for me?” and that’s how they learn the information about their routing tables.

Three types of Dynamic Routing

OSPF, EIGRP, BGP. RIP(old so no talk about it).

OSPF (open shortest path first)

the most common one. we have to really understand this because a lot of companies use this.

vendor neutral

• “(open shortest path first)” : this protocol choose the shortest path to send the information

• “its a link state”: As long as they are connected with each other, they share the information.

• “an interior”: used inside the network. within the AS system.

• “uses the AS (autonomous system)” :for the routers to communicate with each other they has be in the same area or the autimouus system. the As is like a company with their own number. You choose which one you want to use, ether 1 or 2. but when you want all your routers to speak, you put then in the AS.

• done worry about first path algorithm.

• “LSDB (Link State Database)": where the routers flood their database with the network information. they share the information together. For ex: if you delete vlan 35 from MA router , NY will also know do the same thing and NJ will also learn and remove it from the database.

• “Areas": if you are in the sam area, you share the same routing table. so if you have all the offices in one area, it will cause network traffic, bandwidth issues and jitters. So we group them in area 1, area 2, area 3 so they can be easily manageable

Advantages of Dynamic Routing

-if these is any deletion, you don’y have to do anything. the routers will be able to do it themselves.

-reduces errors. when you configure it on one side of the network, it propagates through the entire networks. it goes through the other networks.

-if you delete anything, the NY and Nj all learn that MA detected something from its router. Different from static router where you would have to manually go and do it.

-scalable: used for large networks . if you have to configure 200 routes and create then to be able to talk to all the regional offices. can’t do this by static route.

Dynamic routing Vs static routing?

Dynamic routing, you just have do it once and go through the information. The routers will determine, they decide, what is the shortest path to use You just do your configuration. Static router: go through the individual routers and configure the static route. You have to tell the orders to go through the interfaces and the next hop

Main guys

OSPF and EIGRP

EIGRP (Enhanced Interior Gateway Routing Protocol)

made my CISCO(vendors that provides lot so switches)

Difference between OSPF and EIGRP

EIGRP is Enhanced Interior Gateway Routing Protocol, which is a Cisco proprietary, (means it belongs to somebody).

-if you are not using CISCO equipment, it is difficult to use EIGRP. if you have Cisco routers, firewall, you are going to use EIGRP. You can use OSPF but EIGRP is specific for them and it is ideal but not mandatory.

OSPF is (open shortest path First), which is vendor neutral, it means open source. anyone can cause it. in IT it means anyone can use it.

-For mix environment : it means you are not using only Cisco vendor you are using juniper, etc. For example, so if in Ma if one is bison, router is juniper, it is the best to use OSPF

EIGRP - “AD value of EIGRP = 90, External EIGRP =170”

• it has a way of selecting its best path, It is called the administrative distance. internal means 90, external means 170. explanation comes with the lab so don’t worry.

EIGRP- “Hello packet has a 5 second timer and hold-down timer is of 15 sec”

MA router will send a hello packet to NY router every 5 seconds. after 15 seconds, 3 times, and the router doesn’t respond, it means that router is dead. so MA will remove all the information about NY router. MA router will tell itself “My neighbor is dead”

-hold down timer is 15 seconds. if no response, it will drop the router off the routing table.

EIGRP - “Eigrp is a distance vector routing protocol. Distance” means the route metric to reach the

Network. “Vector” means the interface or direction to reach the network.”

-means it calculates the distance.

-MA router will calculate how to get to NJ router, where to of through all the interfaces, it will do the calculation to send the packet.

EIGRP sends “Hellos” at multicast address “224.0.0.10”

every witch or every router as the multicast address when you configure the EIGRP. That is what they use to send the hello packet to each other.

what is a HOP? If I saw what is my next hop “EIGRP supports maximum “255” Hop-Counts.”

from one router to another router. you jump on another router to the router. for for EIGRP, you can have 255 routers. No that important

EIGRP “It can Load Balance on equal and unequal cost paths.”

-if I am sending a lot of traffic through that one hop, you can send the other information to another side

“EIGRP Process operates under the context of “Autonomous System”. “Autonomous

System (AS)” – It represents a common routing domain, in which routers use the same

metric calculation method and exchange routes only with the members of same “AS”

They're all dynamic. all dynamic routers the As system. they should be in the same AS system. if they are not in the same AS, they can’t share the information. so you mean one area with different sections?

EIGRP only supports “MD5 Authentication”.

you can create a password for the routers, so of you get to MA router, you knock and you say the password and it will give you the route. HOW?? so before you go the next hop or send a password? where is the password used?

summary

OSPF AND EIGRP. They are all internal

BGP (Boarder gateway protocol)

is for internet protocols. if you are moving across the internet. For you to me able to move across the world, you need BGP. s the routing protocol that governs how data packets travel across the internet.

in google type EIGRO vs OSPF

know the metric for the OSPF: “it uses bandwidth to determine the nest path.” and know EIGRP

routing protocol

AI Overview

A routing protocol is a set of rules and procedures that enable routers to exchange information and make informed decisions about the best paths for forwarding data packets across a network.