Cisco Tips & Tricks

May 31, 2006

Resetting BGP session

Filed under: bgp, IP Routing, Router — ciscotips @ 8:59 pm

There are times when route propagated in BGP doesn't exist. As we know that even in link down situation, BGP takes its own sweet time to converge. In this kind of scenario we need to clear advertised routes and in some cases we use the following command

clear ip bgp *

You can also verify the advertised routes with following command

sh ip bgp neighbors A.B.C.D advertised-routes

Even in cases when you change the inbound/outbound policy , you need to reset your BGP session.But using clear ip bgp * can impact all other links as BGP will create routing table from scratch. This is as good as rebooting the router. To minimise impact we can use following command.

clear ip bgp A.B.C.D soft out –> When you make changes in outbound policy

and use

clear ip bgp A.B.C.D soft in –> When you make changes in inbound policy .

Advertisements

15 Comments »

  1. research on this:

    The bgp fast-external-fallover command is used to disable or enable fast external fallover for BGP peering sessions with directly connected external peers. The session is immediately reset if link goes down. Only directly connected peering sessions are supported.

    If BGP fast external fallover is disabled, the BGP routing process will wait until the default hold timer expires (3 keepalives) to reset the peering session. BGP fast external fallover can also be configured on a per-interface basis using the ip bgp fast-external-fallover interface configuration command.

    Examples
    In the following example, the BGP fast external fallover feature is disabled. If the link through which this session is carried flaps, the connection will not be reset.

    Router(config)# router bgp 50000

    Router(config-router)# no bgp fast-external-fallover

    Comment by Roy — May 31, 2006 @ 9:33 pm

  2. Hey There. I found your blog using msn. This is an extremely well
    written article. I’ll be sure to bookmark it and come back to read more of your useful information. Thanks for the post. I will definitely comeback.

    Comment by bed table — September 14, 2012 @ 4:47 am

  3. Your way of telling everything in this article is actually pleasant, every one be capable of effortlessly understand
    it, Thanks a lot.

    Comment by ร้านกาแฟ — March 21, 2013 @ 6:18 pm

  4. Hello to every body, it’s my first pay a visit of this website; this web site includes remarkable and in fact excellent material in favor of visitors.

    Comment by Anonymous — April 8, 2013 @ 12:05 pm

  5. Hey there would you mind sharing which blog platform you’re working with? I’m looking to start my own blog soon but I’m having a hard time deciding between BlogEngine/Wordpress/B2evolution and Drupal. The reason I ask is because your design seems different then most blogs and I’m looking for something unique.
    P.S My apologies for getting off-topic but I had to ask!

    Comment by Nose Job — April 28, 2013 @ 9:52 pm

  6. Thanks for your personal marvelous posting!
    I seriously enjoyed reading it, you could be a great author.
    I will be sure to bookmark your blog and will often
    come back from now on. I want to encourage one to continue your great posts, have
    a nice holiday weekend!

    Comment by metal high sleeper — May 5, 2013 @ 3:06 am

  7. Hmm it appears like your site ate my first comment (it was extremely long) so I guess I’ll just sum it up what I wrote and say, I’m thoroughly enjoying your blog.
    I too am an aspiring blog writer but I’m still new to the whole thing. Do you have any recommendations for newbie blog writers? I’d
    genuinely appreciate it.

    Comment by car beds for children — May 13, 2013 @ 3:23 pm

  8. Hello friends, its impressive paragraph regarding educationand completely explained, keep it up all
    the time.

    Comment by childrens white bedroom furniture — June 15, 2013 @ 10:22 am

  9. Hi, just wanted to tell you, I loved this post. It was practical.
    Keep on posting!

    Comment by “Gambling (2 — July 12, 2013 @ 11:12 am

  10. I hardly leave responses, but i did a few searching and wound up here Resetting BGP session | Cisco Tips & Tricks.

    And I do have 2 questions for you if you don’t mind. Could it be only me or does it look as if like a few of these responses appear as if they are written by brain dead visitors? 😛 And, if you are writing on other online social sites, I would like to keep up with anything fresh you have to post. Would you make a list of all of your public pages like your twitter feed, Facebook page or linkedin profile?

    Comment by Jackpot 6000 — July 18, 2013 @ 6:18 pm

  11. With havin so much content and articles do you ever run into any issues of plagorism
    or copyright infringement? My website has a lot of exclusive content I’ve either authored myself or outsourced but it appears a lot of it is popping it up all over the web without my authorization. Do you know any ways to help protect against content from being stolen? I’d really appreciate it.

    Comment by Aunts and Uncles Canada — August 1, 2013 @ 1:19 pm

  12. thanks for sharing it and it is excellent!

    Comment by Cisco 2960 — September 6, 2013 @ 2:56 am

  13. The south park precocious seven-year-old pageant queen, who
    stars in TLC reality series Here Comes Honey Boo Boo,” they are making them even more popular, more famous, if you will. Is one of their games in south park 2010.

    Comment by www.couchsurfing.org — October 2, 2013 @ 10:43 am

  14. A person necessarily help to make significantly posts I would state.
    This is the first time I frequented your web page and thus far?
    I amazed with the analysis you made to make this particular put up extraordinary.

    Wonderful job!

    Comment by http://bigloutube.com/ — February 13, 2014 @ 8:13 am

  15. Hello! This is kind of off topic but I need some advice from an established blog.
    Is it tough to set up your own blog? I’m not very techincal but I can figure things
    out pretty quick. I’m thinking about creating my own but I’m not sure where to begin.
    Do you have any points or suggestions? Thank you

    Comment by kayfun in stock — June 26, 2014 @ 12:00 pm


RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Blog at WordPress.com.

%d bloggers like this: