CIDR vs. Route Summarization.....same thing?

Ciscopimpenator

It seems that CIDR and route summarization are basically the same thing.

The purpose of both is to summarize routes.

What do you think?

Muchas Gracias

-Ciscopimpenator

MrfixitRight

Ciscopimpenator wrote:

It seems that CIDR and route summarization are basically the same thing.

The purpose of both is to summarize routes.

What do you think?

Muchas Gracias

-Ciscopimpenator

CIDR and route summerization do kind of go hand in hand. But route summarization is not possible without running a classless routing protocol like OSPF or EIGRP.

Ciscopimpenator

On the contrare...


route summarization is enabled by default on RIP and IGRP.
The difference is RIP and IGRP summarize at classful boudaries, where classless protocols can summarize with VLSM's. Also classless protocols can turn off summarization, RIP and IGRP cannot.


What does this all mean?

RIP and IGRP suck.
Use OSPF for your IGP.

Muchas Gracias

-Ciscopimpenator

Netstudent

Correct me if I'm wrong but RIP v2 can turn off Summarization. "No Auto-Summary" command I believe.

NightShade1

They are not the same....
CIDR is supernetting

Lets see it with a practice example... it just the best way to see stuff
Example of summarization

If you had
172.16.12.0/24

172.16.13.0/24

172.16.14.0/24

172.16.15.0/24

This is a class B as you see when you summarize you will summarize it to something higher than /16 but lesst han /24

If i wanted to CIDR i would make the mask less than /16

Example of CIDR


172.16.0.0/16

172.17.0.0/16

172.18.0.0/16

172.19.0.0/16

You can supernet this to 172.16.0.0/14

10101100.00010000.00000000.00000000 -->172.16.0.0/16
10101100.00010001.00000000.00000000 --->172.17.0.0/16
10101100.00010010.00000000.00000000 -->172.18.0.0/16
10101100.00010011.00000000.00000000 -->172.19.0.0/16

As you can see the commmon bits are /14
so we get 172.16.0.0/14


Well in other words the difference between CIDR and route summarization is that route summarization is generally done within, or up to, a classful boundary, whereas CIDR combines several classful networks(this is the key)

For a detailed explanation just google yourself tho....

BTW you can turn off the auto-summary in rip v2....

MrfixitRight

NightShade1 wrote:

They are not the same....
CIDR is supernetting

Well in other words the difference between CIDR and route summarization is that route summarization is generally done within, or up to, a classful boundary, whereas CIDR combines several classful networks(this is the key)

For a detailed explanation just google yourself tho....

BTW you can turn off the auto-summary in rip v2....

Yes Nightshade, you are absolutely correct! And I did "Google" it and found the info below.

From the Cisco Press CCNP Advanced Routing Companion:

"The use of CIDR and VLSM not only reduces address waste, but it also promotes route aggregation, or route summarization."

And from CCNP Self-Study: Building Scalable Cisco Internetworks

"The difference between CIDR and route summarization is that route summarization is generally done within, or up to, a classful boundary, whereas CIDR combines several classful networks."

My earlier information was correct to a point, as OSPF and EIGRP are used in route summarization. Right?

Ciscopimpenator

Wendell Odom is terrible at explaining most things.

Is this guy supposed to be one of Cisco's best writers?

I find better examples and explanations on this forum and random blogs.

Ciscopimpenator

"They are not the same...CIDR is supernetting"

Route summarization is also supernetting so don't get confused there.


According tothe BSCI book, route summarization is knows as route aggregation or
SUPERNETTING.


Anyways the truth is CIDR employs route summarization.

According to BSCI book

"The idea behind CIDR is that blocks of multiple Class C addresses can be combined, or aggregated, to create a larger classles set of IP addresses."



BTW your explanation blew chunks...hahahaha...you might want to go back and review those two concepts....hahahaha

Have a good one

-Ciscopimpenator

MrfixitRight

Ciscopimpenator wrote:

BTW your explanation blew chunks...hahahaha...you might want to go back and review those two concepts....hahahaha

Have a good one

-Ciscopimpenator

No need to be rude, okay. I have only been doing this for 5 weeks, not 5 years. My forte is in troubleshooting desktop, laptop, and printer issues, (which I have been on and off since the late '80's), not Cisco routing protocols and IP addressing. I do think that considering I am attempting to learn something new should be enough. I suppose you never get anything wrong, or get confused with these concepts.

Ciscopimpenator

I was talking to Nightshade...

he was completely confused on his explanation...


I'm just trying to help him. There is nothing like giving other people confusing and mish mosh answers. Sometimes it's better to say you don't know instead of giving other people wordy false answers. Did you read his post? It was completely wrong. Route summarization is supernetting!

I try not to BS my way through life. With technology most of the time you either know it or you don't.

Good luck



-Ciscopimpenator

NightShade1

The only one confused here its you my explanation seems pretty clear to me but whatever...

could be KIND of summarization but they are not the same its like comparing apples and orange and saying they are the same because they are fruits O_o

CIDR is moving talking the network address to the left of the neutral major network
If we have 172.16.1.0/24 we know its a class B and the neutral mask is /16 if i want to use the CIRD then i will want to make the mask less than /16 if we were summarizing then we would want a mask greater than /16 but less than /24


They are just not the same, they do have differneces.


If you were soo sure of what you saying guess you wouldnt be asking this in first place...

If they were the same there wouldnt have any difference in first place and there are!!!

Anyways ill put it to you in simple words so you can understand it. Address agregation takes summarization a step further by breaking the class limits of the major networks addresses when the summarization which is what we taking about here dont break those limits! they are limited to that class limit and thats why in the example i gave up the summarization must be higher /16 but smaller than /24
In both case yeah both reduce the length of the address mask

Moderated

If you dont want to listen me fine go and BS yourself way through life heh

MrfixitRight

Ciscopimpenator wrote:

I was talking to Nightshade...

he was completely confused on his explanation...


I'm just trying to help him. There is nothing like giving other people confusing and mish mosh answers. Sometimes it's better to say you don't know instead of giving other people wordy false answers. Did you read his post? It was completely wrong. Route summarization is supernetting!

I try not to BS my way through life. With technology most of the time you either know it or you don't.

Good luck



-Ciscopimpenator

My bad, I thought you were talking to me. I apologize. I am really trying to grasp this stuff, and have been cramming all weekend and tonight too! I have routing protocols oozing out of my ears!!

Okay, my understanding from what I read on the subject, (and there is a lot of material available!) From Todd Lammle book - CCNP: Cisco Certified Network Professional Exam Notes -

Classless Interdomain Routing (CIDR) A method supported by classless routing protocols, such as OSPF and BGPv4, that allows a group of IP networks to appear to other networks as a unified, larger entity. CIDR is based on the concept of ignoring the IP class of address and permitting route aggregation and VLSMs. This enables routers to combine routes in order to minimize the routing information that needs to be conveyed by the primary routers.

And from the same book:

Route summarization is the process of advertising a large number of networks with one route entry. Route summarization is automatically turned on with RIP, IGRP, and EIGRP. You need to turn off auto-summarization if you have discontiguous networks or if you want to configure manual summarization.

And finally from:CCIE Cisco Certified Internetwork Expert Study Guide
by John Swartz and Todd Lammle
-

Supernetting, which is also called summarization, is the process of combining networks to save routing table entries. For example, it is typically more efficient to advertise 172.16.0.0 instead of 254 subnets, starting with 172.16.1.0 going to 172.16.254.0.

So now the question. Is CIDR the same as Supernetting? Or is Route Summarization the same as Supernetting? Oh, and BTW my CCNA Study Guide (640-801) says that CIDR is and extension of VLSM and route summarization. Using VLSM, you can summarize subnets back to the Class A, B, or C network boundry. This practice is commonly referred to as supernetting. Go figure!

rossonieri#1

MrfixitRight wrote:

CIDR and route summerization do kind of go hand in hand. But route summarization is not possible without running a classless routing protocol like OSPF or EIGRP.

this is a nice - simple and almost correct explanation.

NightShade1

"So now the question. Is CIDR the same as Supernetting? Or is Route Summarization the same as Supernetting?"

No, they are not the same.... the both reduce the lenght of address mask but one break the class limits of the major network address and the other doesnt.....

Ciscopimpenator

NightShade1 wrote:

The only one confused here its you my explanation seems pretty clear to me but whatever...

could be KIND of summarization but they are not the same its like comparing apples and orange and saying they are the same because they are fruits O_o

CIDR is moving talking the network address to the left of the neutral major network
If we have 172.16.1.0/24 we know its a class B and the neutral mask is /16 if i want to use the CIRD then i will want to make the mask less than /16 if we were summarizing then we would want a mask greater than /16 but less than /24


They are just not the same, they do have differneces.


If you were soo sure of what you saying guess you wouldnt be asking this in first place...

If they were the same there wouldnt have any difference in first place and there are!!!

Anyways ill put it to you in simple words so you can understand it. Address agregation takes summarization a step further by breaking the class limits of the major networks addresses when the summarization which is what we taking about here dont break those limits! they are limited to that class limit and thats why in the example i gave up the summarization must be higher /16 but smaller than /24
In both case yeah both reduce the length of the address mask

Moderated

If you dont want to listen me fine go and BS yourself way through life heh

Stop! Stop! Stop!

You are completely wrong.
Go read the BSCI book or go on wikipedia and read CIDR and route summarization.

CIDR is the concept that higher authorities such as IANA allocate IP addresses in contiguous blocks to help promote smaller routing tables. This is accomplished using route summarization and supernetting. Thats it.

Moderated

A public service announcement

-Ciscopimpenator

NightShade1

Moderated

Ciscopimpenator

NightShade1 wrote:

"So now the question. Is CIDR the same as Supernetting? Or is Route Summarization the same as Supernetting?"

No, they are not the same.... the both reduce the lenght of address mask but one break the class limits of the major network address and the other doesnt.....

supernetting = summarization

supernetting does not equal CIDR, like you said earlier

WTF are class limits? Most people say classful or classless, not class limits. CIDR uses summarization. CIDR is a concept of keeping routing tables small by allocating IP addresses properly.


I learned this today because I did some major research.

I'm just letting you know because you are wrong and this is an important concept.

-Ciscopimpenator

Ciscopimpenator

NightShade1 wrote:

Moderated

I just broke it down, I don't need your help. Moderated


-Ciscopimpenator

Ciscopimpenator

Moderated

NightShade1

Class limit means

if you got a class B you know that the classfull mask of that is /16

breaking the class limits is going from a class B to a class A by for example doing routing aggregation what i mean is that i could have 4 class B on /16 and reduce it to one class A of /14... here i would be breaking the limits of the class....

i just wonder why in books when they doing this

172.16.12.0/24
172.16.13.0/24
172.16.14.0/24
172.16.15.0/24

172.16.12.0/22 they refer that as a route summarization

And when we are doing
172.16.0.0/16
172.17.0.0/16
172.18.0.0/16
172.19.0.0/16

172.16.0.0/14 they refer that as a route aggregation...

I mean they are the same why not calling it both route summarization!!!

ah yeah damn to make the difference....

You are completely wrong.
Go read the BSCI book or go on wikipedia and read CIDR and route summarization.

well so CCNP Self-Study: Advanced IP Addressing says they arent the same.... i actually bealive more to that book than wikipedia in which anyone can go and upload information lol
in fact i found an article of that book on internet http://www.ciscopress.com/articles/article.asp?p=174107&seqNum=4&rl=1
go to the end of the page you will see that the authors make the differnce between them.


Anyways just take it or leave it if you dont want to listen me then its cool tho....

EdTheLad

Ciscopimpenator wrote:

NightShade1 wrote:

"So now the question. Is CIDR the same as Supernetting? Or is Route Summarization the same as Supernetting?"

No, they are not the same.... the both reduce the lenght of address mask but one break the class limits of the major network address and the other doesnt.....

supernetting = summarization

supernetting does not equal CIDR, like you said earlier

WTF are class limits? Most people say classful or classless, not class limits. CIDR uses summarization. CIDR is a concept of keeping routing tables small by allocating IP addresses properly.


I learned this today because I did some major research.

I'm just letting you know because you are wrong and this is an important concept.

-Ciscopimpenator

Maybe you should try and understand when someone is pointing you in the right direction.
Nightshade has tried to explain summarization is to the right of the major network boundary while supernetting i.e. CIDR is to the left of the major boundary.
This concept has been explained many times in this forum by myself and others, maybe you should use the search engine before you start the insults.

NightShade1

EdTheLad wrote:

Ciscopimpenator wrote:

NightShade1 wrote:

"So now the question. Is CIDR the same as Supernetting? Or is Route Summarization the same as Supernetting?"

No, they are not the same.... the both reduce the lenght of address mask but one break the class limits of the major network address and the other doesnt.....

supernetting = summarization

supernetting does not equal CIDR, like you said earlier

WTF are class limits? Most people say classful or classless, not class limits. CIDR uses summarization. CIDR is a concept of keeping routing tables small by allocating IP addresses properly.


I learned this today because I did some major research.

I'm just letting you know because you are wrong and this is an important concept.

-Ciscopimpenator

Maybe you should try and understand when someone is pointing you in the right direction.
Nightshade has tried to explain summarization is to the right of the major network boundary while supernetting i.e. CIDR is to the left of the major boundary.
This concept has been explained many times in this forum by myself and others, maybe you should use the search engine before you start the insults.

Ty EdTheLad at last someone that actually knows.....

he-man

So whats subnetting then?


Keep up the good work guys, you make studying so much more fun

mikej412

EdTheLad wrote:

Maybe you should try and understand when someone is pointing you in the right direction.
Nightshade has tried to explain summarization is to the right of the major network boundary while supernetting i.e. CIDR is to the left of the major boundary.
This concept has been explained many times in this forum by myself and others, maybe you should use the search engine before you start the insults.

Yeah, what Ed said.