ArticlesReader.com Menu
Newest Articles
Most Viewed Articles
ArticlesReader.com RSS
Submit Article
Login
Signup
Search the articles

Articles Main Categories
Advice
Animals
Automobiles
Business
Career
Communications
Computer Programming
Computers
Entertainment
Environment
Family
Fashion
Finance
Food
Health & Medical
Home & Garden
Humor
Internet Business
Internet Marketing
Legal
Leisure & Recreation
Marketing
Other
Politics
Reference & Education
Religion
Self Improvement
Sports
Technology & Science
Travel
Writing
Subscribe
Receive alert message from us when new articles submitted to our site for free.

Enter your name

Enter your email

Syndicate

















Related Products
Home::Computer Certification

Cisco CCNP / BSCI Certification: The Local Preference BGP Attribute

Author : Chris Bryant, CCIE #12933
When studying for your BSCI exam for the CCNP, you get your first taste of BGP. One of the major differences between BGP and the other protocols you've studied to date is that BGP uses attributes to describe paths, and to influence the selection of one path over the other.



In this free tutorial, we're going to take a look at the Local Preference attribute and compare it to the Cisco-proprietary BGP attribute "weight".



The Local Preference (LOCAL_PREF) attribute is used to influence how traffic will flow from one Autonomous System (AS) to another when multiple paths exist. For example, if AS 100 has two different paths to a destination network in AS 200, the LOCAL_PREF attribute can be used to influence the path selection.



The major difference between the Weight and LOCAL_PREF attributes is that when the LOCAL_PREF attribute is changed, that change is reflected throughout the AS. The new LOCAL_PREF value will be advertised to all other routers in the AS, as compared to the Weight attribute, which is locally significant only. If you change the Weight for a path on one router in an AS, the other routers in the AS will not learn of the change.



A route-map can be used to change a local preference value. For example, if you want to change the local preference value to 200 for the path advertisement 10.2.2.0/24 coming in from neighbor 10.1.1.1, there are three steps involved. First, write an ACL matching the remote network you want to change the local preference for.



R1(config)#access-list 5 permit 10.2.2.0 0.0.0.255



Second, write a route-map setting the local preference to 200. This will double the default value of 100, and the path with the highest local preference will be the preferred path.



R1(config)#route-map PREFER_PATH permit 10



R1(config-route-map)#match ip address 5



R1(config-route-map)#set local-pref 200



Finally, apply the route-map to routes that are being received from 10.1.1.1.



R1(config)#router bgp 100



R1(config-router)#network 10.1.1.1 route-map PREFER_PATH in



R1 will then advertise this new local preference value to all other routers in AS 100 - all of its iBGP neighbors.


Article Source: http://www.articledashboard.com





Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (www.thebryantadvantage.com), home of free http://www.thebryantadvantage.com/">CCNA and http://www.thebryantadvantage.com/ccnpstorebsci.htm">CCNP tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages. Video courses and training, binary and subnetting help, and corporate training are also available. Pass the http://www.thebryantadvantage.com/UltimateCCNAStudyPackage.html">CCNA exam and http://www.thebryantadvantage.com/ccnpstorebsci.htm">BSCI exam with Chris Bryant, CCIE #12933!

For a copy of his FREE ebooks, “How To Pass The CCNA” and “How To Pass The CCNP”, visit the website and download your copies! Get your http://www.thebryantadvantage.com/">CCNP certification with The Bryant Advantage!





Spam emails More free articles

Related articles


  1. Cisco Certification: The OSI Model Isn't Just For Exams Anymore!
  2. Cisco CCNP / BSCI Certification: Introduction To ISIS Terminology
  3. Cisco CCNA Certification: The Value Of The CCNA And CCNP
  4. MCSE 70-290 Certification Primer
  5. Cisco Certification: A Survival Guide To The Cisco Cable Jungle
  6. Cisco Certification: Taking Your First Certification Exam
  7. Cisco Certification: Building Your Home Lab, Part II
  8. Cisco Certification: Building Your Own Home Lab, Part I
  9. Cisco Certification: Introduction To ISDN, Part V
  10. Cisco Certification: Introduction To ISDN, Part III
  11. Cisco Certifications Overview
  12. Cisco Certification: Introduction To ISDN, Part I
  13. Cisco Certification: What To Do DURING Your Exam!
  14. Cisco Certification: The Joy Of Hex
  15. Cisco Certification: How To Become A Truly Valuable CCNA
  16. Cisco Certification: Five Things To Do DURING Your CCNA Exam
  17. Cisco CCNA Certification: Becoming A Truly Valuable CCNA
  18. Cisco CCNP / BSCI Certification: The BGP Attribute “MED”
  19. Cisco CCNA Certification: Cisco Switching Modes Tutorial
  20. Cisco CCNP / BSCI Certification: The Local Preference BGP Attribute
  21. Cisco CCNA Certification: Error Detection vs. Error Recovery
  22. Cisco CCNA Certification: Broadcasts, Unicasts, And Multicasts
  23. Cisco Certification: Recertifying Your CCNA and CCNP
  24. Computer Certification: Become A Utility Player
  25. Cisco CCNA / CCNP Home Labs: Developing Troubleshooting Skills
More related feeds
CIsco CCNP / BSCI Exam Tutorial: Introduction To Policy Routing
extcommunity BGP extended community attribute. interface Output interface. ip IP specific information. level Where to import route. local-preference BGP local preference path attribute. metric Metric value for destination routing ...

Top Adding: Cisco CCNP BSCI Certification The Local Preference BGP ...
One of the major differences between BGP and the other protocols you ve studied to date is that BGP uses attributes to describe paths and to influence the selection of one path over the other. R1 will then advertise this new local pre.

Cisco CCNP / BSCI Certification: The Local Preference BGP Attribute
from 10.1.1.1. R1(config)#router bgp 100. R1(config-router)#network 10.1.1.1 route-map PREFER_PATH in. R1 will then advertise this new local preference value to all other routers in AS 100 - all of its iBGP neighbors.

CCNA, CCNP, CCENT, and Cisco Security Questions - DHCP, OSPF ...
atomic aggregate EF aggregator. Answer: D, E. The BGP attributes are known atomic unit and LOCAL_PREF (local preference) . CCNP /BSCI:. What QoS scheme is defined in RFC 1613? A. DiffServ FIFO BC Integrated Services D. Best Effort ...

Cisco CCNP BSCI Certification The Local Preference BGP Attribute
One of the field differences between BGP and the added protocols you've unnatural to fellow is that BGP uses attributes to exposit paths, and to impact the activity of digit line over the other...

Cisco CCNP / BSCI Certification: The BGP Attribute “MED”
In earlier free BGP tutorials, I discussed the BGP attributes “weight” and “local preference”. These attributes are used to favor one path to a destination over another; for example, if BGP AS 100 has two paths to a destination in AS ...

Cisco CCNA, CCNP, and CCENT Practice Exam Questions - DHCP, BGP ...
E. change the local preference attribute F. configuration Confederations Answers: C, F. route reflectors and Confederations help us to this particular BGP rule. CCNP /BSCI: Which of the following statements is not true a destination ...

CCNA Security, CCNP, And Cisco CCNA Practice Exam Questions: DHCP ...
CCNP / BSCI: What are the BGP well-known discretionary attributes? A. AS_PATH B. origin C. NEXT_HOP D. LOCAL_PREF E. atomic aggregate F. aggregator Answer: D, E. The BGP well-known attributes are atomic aggregate and LOCAL_PREF (local ...

Cisco CCNA, CCNP, And CCENT Practice Exam Questions: DHCP, BGP ...
E. changing the weight attribute C. Topics include DHCP, classless protocols, and BGP route reflectors. CCNP / BSCI: By default, iBGP routers cannot propagate routes to iBGP neighbors that were originally learned from another iBGP ...

Cisco:642-892 Composite Updated
Describe the functions and operations of BGP Configure or verify BGP operation in a non-transit AS (eg, authentication) Configure BGP path selection. (ie, Local Preference, AS Path, Weight or MED attributes) ...

 


 

© 2007 articlesreader.com - All Rights Reserved