Mark,
Just a difference of approach. IPexpert current staff all currently prefer the approach you took. As you mentioned with the other approach there are potentials for loops when you don't match on tags you have already set and overwrite them all at the edge. But this lab was an old lab that is still relevant and allows you to see a different approach. So not looking at the answers and seeing that you solved the lab is a good thing. Means you are not reading the solutions to finish the lab which is a good thing. Just be aware that both are valid approaches. But in my opinion the approach you took is better. When the lab was written it also was not automatic for BGP AS to be added as a tag automatically to a route when redistributed into IGP. This is a new feature. 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/> From: [email protected] [mailto:[email protected]] On Behalf Of Mark Beynon Sent: Tuesday, June 01, 2010 5:51 AM To: [email protected] Subject: [OSL | CCIE_RS] Vol 1 lab 15 all tasks! thanks so many questions after doing this lab... i worked my way through it quite confidently, and ended with no issues, no loops. I did make some fundamental mistakes, but ended up with full connectivity...maybe no loops due to my mistakes.. i was surprised to find however when i read the DSG that my route-map approach was so different than the solution guide. i had taken the approach shown in VOD and denied protocol x from entering protocol X, match everything else be for tagging the remainder as tag Y. And at each point i done that for all protocols in the topology. so going into RIP from OSPF, i denied RIP (tag 120), matched and permitted BGP (tag 200) and EIGRP (90), and set tags on all other routes to 110. And i took the same approach at all other points. Now i know i missed that i should differentiate between the two separate islands of OSPF and EIGRP, so i would have therefore instead... denied RIP (tag 120), matched and permitted BGP (tag 200), EIGRP (7800,12348) and OSPF (567), and set tags on all other routes to 110. This is still not close to the DSG... The DSG doesn't even mention matching tag 7800, so i would suspect that those routes would get redistributed, and overwritten as tag 110, and loop potential. I figure that this wont actually happen, as the routes will actually be in R8's Eigrp 12348 table as connected, but this is just one example i can see. i'm not sure if my approach was valid (if corrected in terms of the ospf/eigrp islands) but just suboptimal under these particular circumstances, or if it is just plain wrong. I'm also not sure why we tag BGP and OSPF separately at R5 and R6 (eg 2005/2006 and 1105/1106). any guidance appreciated! im am going to do it again, but having starred at the solution guide so long i am not sure i know the answers so may not have much benefit. I want to solidify an approach that works in all scenario's. i though i had this after the VOD, but this lab has left me questioning...
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