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Thread Index [isp-bgp] AW: Re: BGP Advertisement question..
If I remember correctly, the network command always generates routes with the "I" attribute. To get an incomplete attribute one would need to do a "redistribute igp" in the router bgp ASN config. (that would be a really bad idea)... The behavior is cisco though (I am not sure if juniper does this)... I have a bunch of quagga/zebra boxes and they will announce anything in the network statement (even if there is no route for it) and it always has the origin attribute set to "I". John :) -----Ursprüngliche Nachricht----- Von: James [mailto:haesu@...] Gesendet: Tuesday, May 11, 2004 8:04 PM An: isp-bgp@isp-bgp.com Betreff: [isp-bgp] Re: BGP Advertisement question.. hmmmm.. i may be way wrong on this, but i am just curious though... If i were carrying that /24 in say.. an IGP.. in this setup (feel free to let me know if I am not interpreting this correctly), bgp would advertise the prefix through the manual "network a.b.c.d mask x.x.x.x" configuration statement, since IGP would have lower admin dist than a floating static. Now... let say IGP bombs out, and now we are down to floating static being the active route. I am not really sure if BGP would remain non-flapping state here... b/c since its now switching to 'redistribute static', wouldn't the origin-type change from I to "?" (incomplete) since the prefix is now being learned by another "protocol"? Or is this not the case with static and connected routes being redistributed? I am not sure if the incomplete origin type applies to static/conn routes as well, although i would guess it woudl since its still being redistributed.. hence.. why i am asking :-D -J On Tue, May 11, 2004 at 08:51:45PM -0600, James Edwards wrote: > How are you carrying 203.23.194.0/24 in routing ? > ie "sho ip route 203.23.194.0/24" > > BGP has to learn 203.23.194.0/24 from > static or connected routes, also it can learn this > prefix from another routing protocol. > > One way is to nail static routes into > BGP: > > router bgp 17766 > redistribute static > ! > > ip route 203.23.194.0 255.255.255.0 null 0 255 > > This is a very stable way to do BGP, you are least > likely to flap you advertisements if they are nailed > to a static route. > > This assumes you have 203.23.194.0/24 carried > by something else, like an IGP, which will > be preferred over this static route to null. > The 255 weight takes care of this. If you do not > have 203.23.194.0/24 in your routing table, ie > "sho ip route 203.23.194.0/24" can't find this prefix, > we will need more information. > > Content-Description: footer > > _______________ ______________ > Content-Description: footer > To unsubscribe via postal mail, please contact us at: > Jupitermedia Corp. > Attn: Discussion List Management > 475 Park Avenue South > New York, NY 10016 > > Please include the email address which you have been contacted with. > -- James Jun TowardEX Technologies, Inc. Technical Lead Network Design, Consulting, IT Outsourcing james@... Boston-based Colocation & Bandwidth Services cell: 1(978)-394-2867 web: http://www.towardex.com , noc: www.twdx.net _______________ ______________ To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with. To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
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