Cisco Router Summarization

[@hongkim4528]

Even 10 years ago, you still explain best. I was trying to refresh my memory on route summ and you rock, Keith! I'm so grateful to have great resource like you! Keep up the great work. Finally I'll be taking CCNA exam tomorrow(Thanks to you). No matter what outcome is, I'll keep trying like you said. Thank you, Keith.

[@KeithBarker]

Thank you Hong Kim!

[@ankoorsen4316]

You are a god, its been 12 years since this video has been uploaded and I have already spent like an hour or so today for a crisp explanation on summarization and been through fairly recently uploaded videos on several channels but this one is the best . You are actually OG of I.T.

[@oat-tennis]

by far, best route summarization video i've seen on youtube. most of them do not show entering the calculated summarize network route in actual router. This clearly show what router will react when it has new route. super clear.

[@hajjabuamin]

This is still helping after almost 10 years, thank you Keith

[@KeithBarker]

Thank you Hashem Ouaida! Some videos just keep on giving. Thanks for the feedback!

[@hajjabuamin]

@@KeithBarker Thanks for replying, I just passed my CCNA 2 days ago and I wanted to thank you. I loved your videos on the CBTBNuggets and i loved your labs as well. Thanks again

[@KeithBarker]

Glad to hear it was useful for you. Thank you for your comments. Best wishes, Keith

[@tapkaBbabkax007]

Keith Barker , kindly expressing my thankfulness for such a detailed video. I understood how to calculate the best route. Now it's possibly to increase productivity of network equipment. Also I figured out that this method is suitable for each routing protocol. Going to practice more. Bits clearly show how to cut to get the desired!

[@KeithBarker]

Hi Angel- Thanks for the comments. I appreciate it. Best wishes, Keith Barker

[@kickerpunter]

I can't tell you how many video I've watched and articles I've read on supernetting trying to understand it for my ICND1 exam. Breaking it down into binary helps so much. Thank you!!

[@majormadness4817]

I see your point about the information already being out there on Wendell's site. Just wanted to say thanks for all the awesome videos that you've made on the subject. Because of people like you, Wendell and Jeremy it made getting my CCNA much easier! Looking forward to starting on Route soon! See ya around CLN. Thanks again!

[@samueladebowale8303]

Thanks so much Keith!! Been looking for the easier way to explain to my Students in the Academy and this right here has done the magic for me. Thanks much for posting the video!!!!

[@josephpmans]

Oh thank you Keith, you finally provided me with the missing piece!

[@austinpeelor8408]

Fancy meeting you here!!!!

[@josephpmans]

@@austinpeelor8408 Indeed

[@prashantmorgaonkar3095]

Keith, High five for a easy to digest but professional presentation !

[@KeithBarker]

Hi Major- Thanks for the Post. Wendell is one of my favorite authors, and I certainly understand why you enjoy the methods he teaches. He has that method posted at the ccnaskillsDOTcom site for everyone to use, so I don't know that a video would be required using his exact method. Thanks for the post, Keith Barker

[@btharvey92]

This is a brilliant video, having a bit of trouble with my CCNA 2 practical, this is superb, thanks!

[@KeithBarker]

Hello- The summary of 23.1.2.0/27 covers the range of: 23.1.2.0 - 23.1.2.31 (which doesn't cover the range of IP addresses). Does that help with your question? Keith

[@mellord83]

Route summarization is such a cool topic. It is basically using subnetting. Did my CCNA ten years ago and this was great refresh my knowledge

[@IamDjVoz]

Thank you so much i read the book, saw it on class and still had a lot of doubts your video made it crystal clear

[@oliviersama2150]

wow! That`s very good and clear. I was so confused with ipv4 summary.Thank you Keith, you are the best teacher ever!! :)

[@gg.wellplayed]

I'm looking for a short video with detailed explanation and found this, thanks Keith

[@KeithBarker]

Glad it was helpful!

[@chirunanda]

Thank you very much........ It provided me an great information regarding Summarization....

[@KeithBarker]

The block size for a /27 is 32. First subnet would be 23.1.2.0/27 and the next one would be 23.1.2.32/27

[@KeithBarker]

Hi Said- That is great news, thank you for letting me know. Best wishes on your exams, Keith

[@rameunknown]

This was an awesome explanation. Keep it up buddy.

[@verticostate]

Im so glad i'd watched this vid again.. I get it now. you rock Keith.

[@KeithBarker]

Excellent. Glad it worked for you.

[@Mike-bq7uz]

greatest cisco instructor ever....hands down

[@djbneozen]

I get the route summerization. Perfectly explained. So here is a question. Why does the EIGRP route show 23.0.0.0 /27 on R9.... Instead of 23.1.2.128 /27 ?

[@LtShifty]

Hey Kieth, yet another great video: Just in time to as I'm covering summarization right now. I'm just getting stuck into CCNP ROUTE, do you have any tips for studying that you yourself have used to get to where you are now as a CCIE? Thanks, and keep the video's coming :)

[@kepenge]

Hi Keith, Great video so one question what about if I add another router outside of the range of 23.1.2.128 - 23.1.2.159. do I need to recalculate the best summary or just advertise that new nework? best regards, Alcides

[@jeanettemorgan9457]

You simplified this technique to the tee. Have been studying CCNA for 2 years, and now, all the puzzle is coming to one big picture. I watched you and others when I didn't know what I was looking at. Summary routes made me wonder. Where did the reduced subnet mask come from. Ok. Ok. Ok. Thank You. :)

[@keithbarker4353]

Glad it is helping. Thank you for the kind feedback Jeanette! Keith

[@KeithBarker]

That first line for each of the routes, is like an "overview" showing the classful information only. It happens for 1, 2, 3, 4, 5, 6 and 7 as well.

[@cesaraumejia]

Great summarization of Route Summarization. Thank you.

[@KeithBarker]

I am sorry. I don't completely follow what your question is. You may want to post on the Cisco Learning Network, where there are lots of folks who can respond. Perhaps there, with a faster back and forth discussion, you can get the answers you are looking for.

[@KeithBarker]

Thanks for the feedback! Keith

[@MuhammadKhan-yl7mt]

Excellently explain and digested.

[@KeithBarker]

Hi Mike. That is very kind of you to say. Thank you. Keith

[@BismillahCollege]

hi keith, absolutely you made my doubt clear. because i am almost finished my CCNP ROUTE studying and still had some doubt with route Summarization. but it looks like 95 persent i am alright even though i am asking my self how does it cover the range you mentioned and whch way. but all other is perfectly understood

[@Flienlow]

Excellent Video Keith!

[@shirleylove979]

Love you keith. Your videos are really helpful.

[@uthmaan2002]

Refer to the exhibit , what is the most efficient summarization that R1 can use to advertise its networks to R2?

[@jlinhart16]

Dude, you're a beast!

[@rafiroomi]

you made it really easy ! cheers keith

[@qasion]

What would be the difference if you summerized likle this 23.1.2.0/27?

[@squidiebah]

Good video Keith

[@uttambaroi]

Keith is superb........!

[@Brightpeom]

that is fantastic .. nice work dude

[@dikair]

Really nice video thank you Sir

[@syedifranali5953]

Amazing explanation.

[@KeithBarker]

Thank you syed Ifran ali!

[@majormadness4817]

I think this is a good video for understanding the basics but I prefer Wendell Odom's decimal way of doing it, much faster! You should make a video of that if you got the time Keith. I see your mug at CBT Nuggets, hanging out with Jeremy now huh? If anyone's interested in the faster way just Google Wendell Odom calculating the best summary route.

[@qasion]

Not really, how did you come up with that rang? Thanks.

[@MichaelPierredotcom]

Thanks for this :), video helps with reading text. I got the point now.

[@davehee6]

Can anyone help with the range ...I can't see where the 159 is coming from. I thought that the last address 148/30 was 4 slots which takes you to 152 so where does the 159 come from??

[@hphdd]

You are right. The last reachable address in this scenairo is .151. This example is not perfect as the addresses form .152-.159 are not in the network.

[@JAY-uk3cq]

how to did you get the 159 at the end of the range

[@earthman7676]

A /27 (.224) gives you 32 addresses. .128 is the first address of the subnet and .159 is the last address.

[@oat-tennis]

correction for earthman7676 :). The /27 (.224 mask) is correct with the network block size of 32 host per subnet. .128 is a network address. Your 1st usable address would be .129 - .158, The .159 is a broadcast address. The block size of 32 will be 0, 32, 64, 96, 128, 160.

[@oat-tennis]

i guess Keith is just saying that it cover the range of network all the way to .159. which is anything belong to the .128 network.

[@navymiguelito]

earthman7676 is correct even if he did include the subnet and broadcast address. But the IP address in question was the broadcast address .159, and technically it's still in the same sub network for .128 even if it's not a usable host address. Yes, I realize I'm commenting a year later :)

[@qasion]

During the test and since time is restricted, it will be hard to write in bineries to find out the answer to these kind of questions, any other short solution?

[@mellord83]

That is why is best to do lots of labs and exercises with binary to decimal and really master it before taking the exam.

[@djbneozen]

Yes. But on a classful rep that would still cover the routes it would be 23.1.2.0 /27 (that is a .255 for the first 3 octets) What am I not understanding here. Why does a /27 look like a /8, when the nearest classful number is a /24? I apologize in advance for my ignorance sir.

[@blipit1]

Just a thought - could this not have been summarised more efficiently using 23.1.2.128/28 and 23.1.2.148/30 - its 2 advertisments but you don't advertise subnets you are not using.

[@brooklynzoo81]

Great video.

[@zeroframe9426]

all those point to point links could be summarised in a block of size 4 with a prefix length of /26 but since those addresses are not contiguous that cant be accomplished thats why you always keep them last when you are subnetting your network. big summarizations are never good idea

[@tanselervansel1648]

Thanks KevinI m the beginner and I m learning too much from your courses.

[@racheljohnson8947]

Thanks Keith! You Rock! I get it!

[@extramild1]

Very helpful - thanks

[@1nt3rnetz]

Perfect! Thank you!

[@novadhd]

it is easier to find the mask with the correct block size to cover your needed IP addresses.

[@AmerikkkaGuitars]

thanks

[@ImH555]

perfect ::)

[@hedgeduck1]

you're intro drives me crazy