I don’t know yet how often I will post such an article, so lets see how it will evolve

IPExperts Cisco’s STP Toolkit

Overview about the STP Enhancements from Cisco

Cisco was not going to sit and wait around for the standards bodies to enhance Spanning-Tree Protocol so that it would converge faster and be more safe to implement. Instead, Cisco has been hard at work creating tools that could improve the protocol. Here is some review about these various tools.

IPExperts BPDUFilter in Action

Article about the Spanning-Tree Protocol BPDUFilter feature

What if you have the rare circumstance that you want to prevent a port on your switch from sending BPDUs? This is one of the jobs that can be accomplished by BPDUFilter. You need to be very careful with this feature in the lab exam, as well as your production network, of course. That is because this feature not only prevents the sending of BPDUs by a port, but it can also result in a port ignoring BPDUs that are received. Of course, this can lead to a Layer 2 loop in your environment.

IPExperts RootGuard in Action

Article about RootGuard, how it works, is configured and tested:

Many Layer 2 implementations these days have Cisco switches facing customers or partners and there is a risk of inadvertent or malicious Spanning Tree Topology manipulations. Remember from previous posts that STP will reconvergence the topology based on the receipt of what we term superior BPDUs. The Root Guard feature guards a port or ports against such an occurrence by moving the port into a root inconsistent state (effectively disabled) based on the receipt of one of these superior BPDUs.

Cisco on How to properly and safely collect debugs on an IOS router

Actually written for Voice debugs, but if you change the debug commands to something else, it can be useful for other debugs too.

Three Articles on Routing-Bits about Cisco’s OTV(Overlay Transport Virtualization):
Cisco OTV (Part I)
Cisco OTV (Part II)
Cisco OTV (Part III)

OTV(Overlay Transport Virtualization) is a technology that provide layer2 extension capabilities between different data centers. In its most simplest form OTV is a new DCI (Data Center Interconnect) technology that routes MAC-based information by encapsulating traffic in normal IP packets for transit.

The Emulator can be downloaded from the Cisco Developer Community, you’ll need a Cisco.com User Login to download the Emulator

To be able to run the Emulator, you’ll need a VM Player, JDK 1.6 (or higher) and the 7-Zip unzip program. The Cisco UCSPE v1.4 release notes are good starting point on how to get the Emulator up and running.

I got the Emulator up and running on my MacBook Pro with VMware Fusion and am looking forward now to play around with it

Have fun

• Upcoming changes to every CCIE Lab Exam
  • Protecting the integrity of the CCIE certification
  • Robust, matured results-based grading engine
  • Heuristic logic embedded into task wording
  • Accuracy and detail of lab score reports
  • Cisco’s CCIE Lab Delivery System and virtualization for mobile labs
  • No re-reads
• CCIE Voice
  • Next blueprint version expectation
  • Topics for current and next blueprint versions
• CCIE Data Center
  • CCIE Storage grows up
• Reason behind Cisco.com CCIE Statistics web page being removed

Have fun: ‘Cisco Live! 2011′ – Future of CCIE Voice, Data Center and Overall CCIE Program

Hi Pashtuk,

Under the technical definition of a CLASS C network, IE using classes. 192.168.0.0/16 is NOT a class C network. So ‘Class C: 192.0.0.0/3 le 32′ would also block or allow that ‘supernet’ of Class C’s, which isn’t a Class C in itself. Old-school routers (ie RIPv1) would convert the mask to /24,Class C is technically:
bits 1-3 110 + a 24 bit mask.

Cheers,KK

check out http://www.ietf.org/rfc/rfc791.txt“in class c, the high order three bits are one-one-zero, the next 21 bits are the network and the last 8 bits are the local address.”so the technically correct Class C prefix list is:
192.0.0.0/3 ge 24 le 24

you wouldn’t use that in the real world though 

You are right if we are talking about the old “classical” concept of Address Classes with their definition of the subnet mask.

Nonetheless the classical concept does not really matter much anymore nowadays, even though the terms Class A/B/C are still in use. Most of the time if we talk about a Class C network today a /24 subnet is thought off, no matter to which original Class the subnet belongs too.

On another occasion we can also talk about Classes in the meaning of ranges grouped into those defined classes (as used in the article).  In that case, it doesn’t matter what the typical subnet mask was, it only matters that we are able to match every subnet out of that range no matter which mask it got.

It does not have much to do with a real world approach, as a lot of the CCIE stuff I had to learn, but it belongs into the stuff a person has to know for the CCIE lab.

What’s going on?

networking-forum.com in association with Cisco Press is giving away 5 free copies of IPv6 for Enterprise Networks.

This is a monthly event so check back next month if you already have the book above.

How are the winners chosen?

It’s simple, add yourself to the forum’s ‘Cisco Press Book Giveaway’ group. Yep, that’s it.

1) Go to your User Control Panel
2) Select the ‘Usergroups’ option on the left
3) Select the ‘Cisco Press Book Giveaway’ radio button
4) Make sure the drop-down menu says ‘Join selected’ and hit the ‘Submit’ button

You should receive an email confirming that you’ve been added. Or you can view the members of the group to ensure your username is on the list.

Towards the end of the month, the forum staff will close the group and randomly select the winners. The winners will be announced in this thread and they will have a few days to provide their shipping information.

Other details

• Neither networking-forum.com (Amoeba Solutions LLC) nor Cisco Press is responsible for issues with this giveaway.
• There will be mistakes made. Don’t get mad or sue. Simply enter next month’s giveaway.
• The rules and or details may change at any time.

News/updates/changes

Any news/updates/changes will be posted here.

What’s going on?

networking-forum.com is offering a scholarship to one person who would like to earn a Cisco Certified Network Associate specialization certification (CCNA Security, CCNA SP Operations, CCNA Voice, or CCNA Wireless). The scholarship will provide study material, a separate forum specifically dedicated to the candidate for his or her use during their studies with feedback from the site’s members, and reimbursement of the exam fees after they pass their exam.

The Specializations/Exams

• CCNA Security – Implementing Cisco IOS Network Security (640-553)
• CCNA SP Operations – Supporting Cisco Service Provider IP NGN Operations (640-760)
• CCNA Voice – Administering Cisco Voice and Unified Communications (640-461)
• CCNA Wireless – Implementing Cisco Unified Wireless Network Essentials (640-721)

How is the recipient chosen?

To qualify for the scholarship, candidates will need to write an essay about why they want to earn their CCNA specialization certification and why they make a good candidate for the scholarship. All essays must be received by May 18th, 2011 and posted in this thread. The essays will be judged by our staff and a few prominent members. The recipient will be announced in this thread and notified via a site private message on May 25th, 2011.

The Judges

• Steve – networking-forum.com
• ibarrere
• Vito_Corleone – AlwaysTheNetwork
• mellowd – Darren’s CCIE mission
• Infinite – Broken Network
• eaadams
• stretch – PacketLife

What is expected of the recipient?

The recipient of the networking-forum.com CCNA Specialization Scholarship is expected to do the following:

• Keep the community informed of their progress by participating in the dedicated forum.
• Write 3 750+ word blog posts on a topic of their choice.

Other details

• CiscoPress is sponsoring the scholarship by providing books. Thanks to them for supporting the site and the cause.
• The recipient has 3 months to pass their exam after being chosen.
• The recipient must have an active CCNA to qualify for the scholarship.
• Proof of the passed exam(s) must be provided to receive reimbursement.
• A picture of the candidate’s face and dated score sheet will need to be posted on the site or sent to Steve.
• Reimbursement for passed exam fees will be made via PayPal.com or check and will not exceed $250 USD.
• The recipient can not be reimbursed by another party for the same exam.
• The rules and or details of the scholarship may change at any time.

Hi,

How you will convert 0008.209a.081b in link-local address. First step is ok where u insert FFFE i.e. 0008.20FF.FE9a.081b
issue is 2nd step, how to convert 0008 to binary?
I have done reverse engineering from link-local address
link-local address is FE80::208:20FF:FE9A:81B

when u convert 208 to binary it comes 10000001000. So my question is how to convert 0008 to 10000000000 (this comes to 400 in HEX)

To get from the  BIA 0008.209a.081b to the link-local address FE80::208:20FF:FE9A:81B we should recap the rules for the modified EUI-64 addressing first:

• FFFE will be put in between the vendor-id (3 most significant bytes) and the extension-id (3 least significant bytes)
• Thereafter the seventh bit, known as universal/local bit, gets inverted.
• At last, change all points ‘.’ to colons ‘:’ and delete all leading zeros

In this case we first insert FFFE into the BIA which leads to 0008.20FFFE9a.081b

Then we have to invert the seventh bit, which means we first change from hex 0008 to binary which leads to 00000000 00001000.
Even though, 0008 in hex only gives out a value of 1000, we must not forget that its still two bytes which means that the leading zeros have to be put in front of 1000 to get a total of 16 (2×8) bits.
If we invert the 7th bit (out of 16) now leads to 00000010 00001000 in hex: 0208. All together its now 0208.20FFFE9a.081b.

Calculators tend to not show the leading zeros if you convert something like 0008 from hex to binary since for them, it does not make sense but in that case it is still important to keep them in mind, they are still there, just set to zero.
A calculator will give you 1000 in binary for 0008, but in that case it has to be 00000000 00001000.

Now delete al leading zeros, change points  ‘.’ to colons ‘:’ and put FE80:: in front of it and then we got your link-local address of FE80::208:20FF:FE9A:81B.

To get back to the issues you had while calculating the link-local, never forget to use all bits while doing this calculation.
A BIA always uses all 6 bytes (or 48 bits), Cisco itself does show the BIAs in three groups of 2 Bytes separated by a point ‘.’

Also 208 does not give 10000001000 (this is Hex 408, there is one zero too much) it is actually 1000001000 or even better 00000010 00001000.
But still to go with your example, you did not invert the 7h bit, it was actually the 13th bit.

Recruiters

I often see posts like “I need a CCIE!! please send your resume to xx@yz.com.” There are quite some variations of that type, but in the end its all the same.
Dear recruiter, please do provide some more information on what kind of position you are talking about, where it is located and (very important IMHO) if the company is sponsoring people from outside the country the job is located in. In the end, you earn money with finding fitting people for the open positions you do have, so why don’t you do write some more about it? Another benefit of more information you (probably) will get less messages from people that don’t fit into the requirements or do live in the wrong part of the world, which leads to less time to invest to write back.

Job Seekers

Most of the time I see comments on job postings like “pls check my profile”.
Guys, do you really think its enough? In the End you want to have a new job, so do invest some time and write a message to the recruiter with more than just “pls check my profile”.. Write a short notice about what you’re currently doing and that you’re interested in the job. DO something for it..

In my opinion, this should be something very basic for both sides. How much time does it take, to be more specific or to write a bit more. In the end both sides are interested to get that up and running, one wants to find people and the other ones try to find a new job/opportunity/challenge.

Its only my 2cent about this thingie and I might have some new “friends” now, but its how I see it .-)

Steve wants to publish a new page every one or two weeks, so if you’re just working on your CCNA or just want to check your knowledge from time to time, you might want to check it out. Its multiple choice, but no explanations so far. If you think you’ve found a mistake you are welcome to post it on the networking-forum.

Now with the new license model, this is not possible any more (at least at the moment), if I lets say need to get into L2TPv3 I need to additionally buy the DATA License which has a list price of $1’000 for a CISCO3900 router! If they stay on that license route and don’t offer options for educational practice it will get hard to learn new (or refresh) things on your own.

Greg Ferro from Etherealmind.com did (re-)start a petition for an educational IOS license, if you’re in the same boat I’d suggest to visit his blog and sign the Petition: http://etherealmind.com/cisco-ios-petition-reloaded/