The AS number is set as a tag when redistributing from BGP to IGP so there is no caveat. Except this is new. Don't expect it to work on older platforms.
Regards, Tyson Scott - CCIE #13513 R&S, Security, and SP Managing Partner / Sr. Instructor - IPexpert, Inc. Mailto: <mailto:[email protected]> [email protected] Telephone: +1.810.326.1444, ext. 208 Live Assistance, Please visit: <http://www.ipexpert.com/chat> www.ipexpert.com/chat eFax: +1.810.454.0130 IPexpert is a premier provider of Self-Study Workbooks, Video on Demand, Audio Tools, Online Hardware Rental and Classroom Training for the Cisco CCIE (R&S, Voice, Security & Service Provider) certification(s) with training locations throughout the United States, Europe, South Asia and Australia. Be sure to visit our online communities at <http://www.ipexpert.com/communities> www.ipexpert.com/communities and our public website at <http://www.ipexpert.com/> www.ipexpert.com From: Aaron Moreck [mailto:[email protected]] Sent: Monday, February 21, 2011 4:44 PM To: Tyson Scott Subject: Re: [OSL | CCIE_RS] Redistribution and BGP Question Anyone have feed back on the BGP tag question? On Mon, Feb 21, 2011 at 2:22 PM, Tyson Scott <[email protected]> wrote: The way that Marko did it is better. The other one was I believe written by Scott Morris back in the day but your point is exactly the shortcoming of the other lab 15 solution. But it achieved the task so it is OK Regards, Tyson Scott - CCIE #13513 R&S, Security, and SP Managing Partner / Sr. Instructor - IPexpert, Inc. Mailto: [email protected] Telephone: +1.810.326.1444, ext. 208 Live Assistance, Please visit: www.ipexpert.com/chat eFax: +1.810.454.0130 IPexpert is a premier provider of Self-Study Workbooks, Video on Demand, Audio Tools, Online Hardware Rental and Classroom Training for the Cisco CCIE (R&S, Voice, Security & Service Provider) certification(s) with training locations throughout the United States, Europe, South Asia and Australia. Be sure to visit our online communities at www.ipexpert.com/communities and our public website at www.ipexpert.com <http://www.ipexpert.com/> -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Aaron Moreck Sent: Monday, February 21, 2011 12:25 PM To: [email protected] Subject: [OSL | CCIE_RS] Redistribution and BGP Question Hi Guys, i need some clarification on redistribution techniques. I was working on Volume 1 Lab 15 and have two questions. The first is the method of route filtering. I attended the online vLecture that Marko did on redistribution and he used route-maps to prevent routing loops in the following manner. Assume we have OSPF, EIGRP, RIP, and BGP in our network (only a single Area/AS for each) route-map ospf-to-eigrp deny 10 match tag 90 route-map ospf-to-eigrp permit 20 match tag 120 route-map ospf-to-eigrp permit 30 match tag 200 route-map ospf-to-eigrp permit 40 set tag 110 However in lab 15 the route-maps were written like this. Doesn't this defeat the purpose of doing mutual redistribution? If one of the routing domains goes way we will no longer have full reachability. Example if we had EIGRP-------OSPF--------RIP EIGRP routes would not make it to RIP. route-map ospf-to-eigrp deny 10 match tag 90 120 200 route-map ospf-to-eigrp permit 40 set tag 110 Second Question is that in the DSG it was mentioned that BGP does not support tags inbound OR outbound. I did know that when redistributing into BGP you cant use the set tag but i was not aware that you can't look at the tag attribute when redistributing from BGP to another protocol. If do a show ip route for a BGP route it does show the tag for the originating AS. So i would assume that if the question states don't redistribute routes originating ins AS 64514 to RIP i could use the tag to filter it. Can someone explain the caveats of the tag in BGP? Routing entry for 102.12.0.0/22 Known via "bgp 64512", distance 200, metric 0 Tag 64514, type internal Last update from 150.100.100.6 3d00h ago Routing Descriptor Blocks: * 150.100.100.6, from 150.100.100.6, 3d00h ago Route metric is 0, traffic share count is 1 AS Hops 2 Route tag 64514 *> 102.12.0.0/22 150.100.100.6 0 100 0 (64514) 19999 3561 ? Thanks in advance everyone _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com <http://www.ipexpert.com/> _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
