What is Classless and Class full Routing?

While sending routing update packet, if it sends subnet mask information also with that packet it is called as classless routing. If it sends packet without subnet mask information then it is called class full routing.

Define Passive Interface?

The router will receive the routing information through that interface but it wont send the routing information through that interface this concept is called Passive Interface. By default it is disabled.

To enable

router#config ter

router(config)#router rip

router(config-router)#passive interface serial 0

Now the routing information is received via serial 0 interface but no routing information is send via it.

Define Split Horizon?

image2

image 3

The Router will not resend the same routing information from which interface it learnt that information is called Split-Horizon. The use of this concept is to avoid the routing loops in Network.

Explanation with Example:

LOOK AT SECOND IMAGE

Here in RA router the 30.0.0.0 information was received via RIP protocol on s0 interface but it wasn’t resend on same interface, it sending only 10.0.0.0 information. Here Split-horizon was enabled.

Lets see what happens when disabled

LOOK AT THIRD IMAGE

Now RA Router is resending the 30.0.0.0 information via s0 interface. It creates routing loops.

This is Split-horizon concept.

Route Propagation:

RIPv1 - Broadcast - 255.255.255.255.

RIPv2 - Multicast - 224.0.0.9.

EIGRP - Multicast - 224.0.0.10.

OSPF - Multicast - 224.0.0.5 - Hello packet 224.0.0.6 - Routing Update.

Protocol Special Properties:

Parameter/Protocol	RIPv1	RIPv2	IGRP/EIGRP
summarization	Auto	Auto	Auto and Manual
VLSM support	No	Yes	Yes
Classless Support	No (Class full)	Yes	Yes
Discontiguous support	No	Yes	Yes
Convergence	Slow	Slow	Fast/Very Fast
Authentication	No	Yes(clear text and MD5)	yes(MD5 only)
Route computation	Bellman-Ford	Bellman-Ford	DUAL

Parameter/Protocol	OSPF
summarization	Manual
VLSM support	Yes
Classless Support	Yes
Discontiguous support	Yes
Convergence	Fast
Authentication	Yes( clear text and MD5)
Route computation	Dijkstra algorithm

Protocol Timers:

Parameter/protocol	RIP	IGRP
Update	30 sec	90 sec
Invalid	180 sec	270 sec
Hold Down	180 sec	280 sec
Flush	240 sec	630 sec

Parameter/Protocol	OSPF
Hello	10 sec
Wait	40 sec
Dead	40 sec

Parameter/protocol	EIGRP
Hello	5 sec
Hold down	15 sec
Active	Manually assigned

Metric Calculation Formula:

RIP

Hop count- To Reach Destination how many router it has to pass.

IGRP

10⁷/Least Bandwidth + ∑ Delay

EIGRP

256*[10⁷/Least Bandwidth + ∑ Delay]

OSPF

10⁸/Bandwidth

Protocols and their Metric Parameters:

RIP

1. Hop count.

IGRP & EIGRP

2. Bandwidth.

3. Reliability.

4. delay.

5. Load.

6. MTU(Maximum Transmission Unit).

OSPF

7. Cost.

What is Metric?

Metric is numeric value used to calculate the best path to the destination. The lowest metric value is considered as best route to the destination. The metric calculation varies based on the type of protocol.

lets take RIP protocol for example,

The RIP protocol calculates metric based on hop count(0-15). To reach a destination one route has metric value 3 and one more route has metric value 5, The route with metric 3 is choosed as best path to reach destination.

What is Administrative Distance?

The Administrative Distance(AD) is the Numerical value that ranges between 0 -255. AD shows the Trust-worthiness of the Protocol.

If AD is high, Trust-worthiness is Less.

If AD is Less, Trust-worthiness is High.

Example and explaination:

You are advertising the same network using RIP and EIGRP Protocol, but the router will take the routes advertised by EIGRP. Why because the AD of EIGRP is 90 and the AD of RIP is 120, the router will prefer the route with low AD(high trust-worthiness) only. thus it takes EIGRP routes.

Protocols and its Administrative Distance

1. Directly Connected - 0.

2. Static Route - 1.

3. External BGP(Border Gateway Protocol) - 20.

4. Internal EIGRP - 90.

5. IGRP - 100.

6. OSPF - 110.

7. IS-IS(Intermediate sys- Intermediate sys)- 115.

8. RIP - 120.

9. ODR(On Demand Routing) - 160.

10.External EIGRP - 170.

11.Internal BGP - 200.

12.Unknown - 255.

What is Hybrid Protocol?

This Protocol has both Distance Vector and Link State protocols characteristics, thus it is called as Hybrid Protocol.

EIGRP belongs Hybrid Protocol.

What is Link State Protocol?

The Link State Protocol is also called as Shortest path Protocol. Here it maintains three tables neighbor table, LSA (Link State adjacency) table, routing table. Link state protocol send updates containing the state of their own links to all routers on the network.

OSPF is a Link State protocol.

What is Distance Vector protocol?

The Distance vector Protocol finds the path to remote network by judging the distance. The vector indicates the direction to the remote network. They send the entire routing table as a periodic update to its directly connected neighbors.

RIP and IGRP belongs to Distance Vector protocol.

What are Protocols used for Dynamic Routing?

There are 3 such Protocols.

1. Distance vector.

2. Link State.

3. Hybrid.

Types of Dynamic Routing Protocol?

There are 4 types dynamic routing protocol.

1.RIP - Routing Information protocol.

2.IGRP - Interior Gateway Routing Protocol.

3.EIGRP - Enhanced Interior Gateway Routing Protocol.

4.OSPF - Open Shortest Path First.

Types of Routing?

There are two types

1.Static Routing.

2.Dynamic Routing.

Static Routing: Manually assigning route to destination by adding information in routing table.

The command for creating static route is

vasanth1406(config)#ip route(network)(subnetmask)(gateway)

Example:

vasanth1406(config)#ip route 10.0.0.0 255.0.0.0 20.0.0.2

Dynamic routing: A routing system that automatically adapts to network topology or traffic changes by advertising its directly connected networks.

What is Routing?

Ans 1: Routing (or routeing) is the process of selecting paths in a network along which to send network traffic.

Ans 2: Routing is a method of finding paths from origins to destinations in a network such as the Internet, along which information can be passed

class C Address

The range of class C address is from 192 to 223(192.0.0.0 to 223.255.255.255).In class first 3 octets is given to network part and the remaining 1 octet is given to host.

Example:

11010101.11010110.00110110.11010101

the private address range is from 192.168.0.0 192.168.255.255.

Class B Address:

The range of class B address is from 128 to 191(128.0.0.0 to 191.255.255.255). In class B 2 octets is given to Network part and remaining 2 octets is given to host part.
Example:

10111010.1100000.01110101.01111000

The private address range in class B is from 172.16.0.0 to 172.32.255.255.