Archive for January, 2010
In this series of posts, we are going to review some interesting topics illustrating unexpected behavior of the BGP routing protocol. It may seem that BGP is a robust and stable protocol, however the way it was designed inherently presents some anomalies in optimal route selection. The main reason for this is the fact that BGP is a path-vector protocol, much like a distance-vector protocol with optimal route selection based on policies, rather than simple additive metrics.
The fact that BGP is mainly used for Inter-AS routing results in different routing policies used inside every AS. When those different policies come to interact, the resulting behavior might not be the same as expected by individual policy developers. For example, prepending the AS_PATH attribute may not result in proper global path manipulation if an upstream AS performs additional prepending.
In addition to that, BGP was designed for inter-AS loop detection based on the AS_PATH attribute and therefore cannot detect intra-AS routing loops. Optimally, intra-AS routing loops could be prevented by ensuring a full mesh of BGP peering between all routers in the AS. However, implementing full-mesh is not possible for a large number of BGP routers. Known solutions to this problem – Route Reflectors and BGP Confederations – prevent all BGP speakers from having full information on all potential AS exit points due to the best-path selection process. This unavoidable loss of additional information may result in suboptimal routing or routing loops, as illustrated below.
We have had many requests to share this forum post with the blog, so here it is. I also wanted to share a conversation Hadi had with Sales here at INE. I am so proud to be a part of INE! I have so much respect for my fellow instructors - and our incredible students!
Kady Dennis: Thank you for visiting Internetwork Expert. How may I help you today?
Hadi Esper: Hi Kady, I dont really have any questions to say.. I passed my CCIE R&S (25869) 2 days ago and wanted to say thank you to the sales team who have been very helpful and supportive of me over the last 1 year and 2 months.. i couldnt have made it without your excellent workbooks nor without ur amazing discounts
We recently spotlighted our new CCIE R&S passers in our newsletter, but we were remiss in recognizing everyone else. Shame on us!
Heartfelt congratulations to ALL of our recent passers!
#13900 Casssio Gomes (SP) (2x)
#17275 Yaroslav Rosomakho (SP) (4x)
#21607 Andriy Yerofreyev (Voice) (2X)
#25664 Vikrant Pundir (SP)
#25719 Mohamed Gazzaz (Sec)
#25722 Bambang Gunawan (SP)
#25793 Flavio Provedel (R&S)
#25809 Brian Luers (R&S)
#25820 Joni Oksanen (SP)
#25821 Steven Clarkin (R&S)
#25823 Branimir Turk (R&S)
#25869 Hadi Esper (R&S)
Cisco has announced a new CCIE track – SP Operations. Read more about it here.
This new track features a written exam release in Q2, and a practical lab exam release in Q3 (that is if they hit their targets). Obviously we will keep close tabs on this new track and its development.
I am looking forward to the many comments of our blog faithful. . .
The topic will be The LATEST Version 4 Exam Format. You will not want to miss this important Open Lecture!
Cisco is prone to making subtle modifications to the format and style of CCIE Lab Exams based on pass rates and student feedback. This Open Lecture brings you up to date with the latest information about the current Version 4.X CCIE Lab Exam.
We look forward to answering the many questions our live students will have in our virtual classroom. Bring them all and be sure to join us live online!
Hello everyone – I posted the second part of our PfR lesson in the CCIE Written Bootcamp tonight. Enjoy!
Do you have technical questions about Lab 1 of our latest, best-selling Volume 2, Version 5 Self-Paced Workbook for the CCIE Version 4.X lab exam?
Do you want to see an instructor discuss the solutions and best possible verifications?
Do you have specific exam strategy questions?
Then do we have the product for you!
Here are the next couple of Lab Meetups in this new and improved series:
- Feb 5 – 11 AM EST US – Volume 2, v5, Lab 1
- Feb 12 – 11 AM EST US – Volume 2, V5, Lab 2
- Feb 18 – 11 AM EST US – Volume 2, V5, Lab 3
Convert to your own timezone here!
Want Even More Improvements:
- Know you cannot attend one of the above? Send your question(s) to firstname.lastname@example.org to ensure your query is fully covered Live, On-Air! Then just be sure to catch the recorded version.
- From all questions submitted (email and live), each Meet-Up will include a free drawing for awesome prizes!
- While we are starting with the first three labs in sequence, we do plan on jumping around per student requests.
- All Lab Meet-Ups and Open Lecture Series sessions will be posted in CoD format the WEEK FOLLOWING the actual event.
- I have received many emails asking about the new INE product I have hinted at…yes, we will announce it fully soon, and provide a sample! This exciting new product works perfectly in conjunction with Lab Meet-Ups and will include the series free of charge. It will be made available to existing Lab Meet-Up customers for a special upgrade price.
As always, stay tuned (RSS) to blog.ine.com for the latest from your Cisco training specialists, and we literally cannot wait to “SEE YOU IN CLASS!”
Be sure to watch the blog over the next several days for exciting announcements about upcoming new and improved products (ATCoD, Lab Meet-ups) and just plain new products (shhhh – still secret) from INE.
For the Open Lectures, you will notice new voices, and interactivity in the sessions. We are also varying the days and times as everyone has requested.
Jan 26 – 2 PM EST US – The LATEST Version 4 Exam Format
Jan 28 – 6 PM EST US – Embedded Event Manager (EEM)
Feb 2 – 11 PM EST US – IPv6 Multicast – PIM
Feb 4 – 11 AM EST US – NetFlow
Feb 8 – 3 PM EST US - Advanced Zone-Based Firewall
Feb 10 – 11 PM EST US – PfR/OER Demystified
Convert to your own timezone here!
We are excited to announce that our CCIE Voice Core Knowledge Simulator has been released! You can try out a sample here. So far, the first 100 questions have been released, and will be followed shortly by additional updates.
The simulation is designed to help prepare candidates for the newly added “open ended” section of the 3.0 Voice CCIE Lab Exam. This new section of the exam consists of four computer based, short-answer questions which candidates have 30 minutes to complete.
The simulator is designed to:
* Pinpoint your areas of weakness on Core Knowledge
* Provide study documents to improve in these weak areas
* Practice with question interpretation and your short-answer responses
Enjoy the questions, and as always, good luck with your studies!