tag:blogger.com,1999:blog-6193417800921617897.post2806700413138860839..comments2023-09-07T04:03:14.584-07:00Comments on CCIE TO BE: BGP - Conditional Advertisement with non-exist-mapdeadhead blueshttp://www.blogger.com/profile/10566569168999502387noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-6193417800921617897.post-37215131917933934492012-12-12T00:50:48.622-08:002012-12-12T00:50:48.622-08:00Zahid,
In case your ISP is giving you default, yo...Zahid,<br /><br />In case your ISP is giving you default, you can match default via ACL or even Prefix-list.<br />More over since we are using route-map, you can match AS-PATH list as well...<br /><br />One of the non supported feature of route-map in conditional advertisement is of next-hop.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6193417800921617897.post-70318596696982157982012-05-01T12:22:24.462-07:002012-05-01T12:22:24.462-07:00Yes this is very helpful in Primary and Secondary ...Yes this is very helpful in Primary and Secondary ISP scenario... <br /><br />I have a doubt... what if both ISP are originating default for me? how to track then?Anonymoushttps://www.blogger.com/profile/04023772615413214184noreply@blogger.comtag:blogger.com,1999:blog-6193417800921617897.post-54410040621884511012011-06-06T05:25:19.445-07:002011-06-06T05:25:19.445-07:00Take another scenario
Say you have a system A (ac...Take another scenario<br /><br />Say you have a system A (active) and B for (backup system in different DC) and both reachable via BGP (Private cloud), now remote nodes can use system A as long as it is reachable and while it will use system B in case system A is not responding or not reachable.<br /><br />System A BGP-GW can advertise system A subnet only and only if it has internet reachability via different uplink (this is conditional advertisement) otherwise, it will stop advertisement of system A subnet casing all remote nodes to use system BAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6193417800921617897.post-33157199696159170472010-10-04T00:09:30.218-07:002010-10-04T00:09:30.218-07:00We can take it this way that if there is a custome...We can take it this way that if there is a customer dual homed to two ISP's for the internet connectivity and dont want the Internet from both the SP's at the same time . Will require this feature to be implemented so that the customer regains connectivity to the internet upon the failure of the primary connection to the SP.asfarnoreply@blogger.comtag:blogger.com,1999:blog-6193417800921617897.post-13349416284812545522010-06-25T11:42:17.061-07:002010-06-25T11:42:17.061-07:00I used a prefiex-list to block the routes in the e...I used a prefiex-list to block the routes in the exist map to enter BGP table, so the route in the exist map in neither BGP table not routing table, but the routes in the advertise map is still NOT sent…<br />So my testing result is "not receiving routes in the exist map from any BGP peer/redistribution" , then router will advertise the routes in the ADVERTISE map...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6193417800921617897.post-66783163431229371472009-02-04T12:48:00.000-08:002009-02-04T12:48:00.000-08:00Hehe, there are lot of things where I ask myself t...Hehe, there are lot of things where I ask myself the same thing :)<BR/><BR/>In this case, suppose you had ISPs in different AS. You only want to advertise a route or routes to one of them. Then if your primary connection goes down (identified by the missing route in the non-exist map) you can then advertise the routes to the backup neighbor.<BR/><BR/>In some cases this might be better than trying to use AS-prepends to influence path selection because with AS-prepends you only have so much control.<BR/><BR/>Hope that helps. If you know any other situations, let me know!deadhead blueshttps://www.blogger.com/profile/10566569168999502387noreply@blogger.comtag:blogger.com,1999:blog-6193417800921617897.post-81071338978334413852009-02-04T12:41:00.000-08:002009-02-04T12:41:00.000-08:00man... i need to know, WHAT is the LOGIC behind th...man... i need to know, <BR/>WHAT is the LOGIC behind this feature ??<BR/><BR/>if i have a subnet X in my table, do not adv Y to "R",<BR/>if i do not have x in my table, advertise Y.<BR/><BR/>you know what i mean, i got the feature, just need to know what i answer when someone aske me, WHY DO WE NEED THIS ??! LOL<BR/>GREAT BLOG !Anonymousnoreply@blogger.com