LSA summarization is not done in/from the RIB. Original Type-3 is created from the computed SPF tree, which in turn is based on the information from Type 1 and Type 2 LSAs. "The routing table structure" in the context quoted is what I called the "computed SPF tree", not the RIB, as the RFC has no control over how RIB is constructed.
-- Marko Milivojevic - CCIE #18427 (SP R&S) Senior CCIE Instructor - IPexpert :: This message was sent from a mobile device. I apologize for errors and brevity. :: On Jan 4, 2013, at 1:20, shiran guez <shiranp3_at_gmail.com> wrote: > Hi All > > I have to agree with Brian and add some to back it up: > > 1) LSA type 1 or LSA type 2 does not need to be filtered or summarized > simply because that are locally significant to the area that they where > generated > RFC2328 > " > > 12.4.1. Router-LSAs > > ... > > The LSA is flooded throughout the particular area, and no further. > > ... > > 12.4.2. Network-LSAs > > ... > > The network-LSA is flooded throughout the area that contains the > transit network, and no further. > > " > > 2) LSA type 3 is generated from the RIB using the SPF algorithm > > "12.4.3. Summary-LSAs > > ... > > The precise summary routes to advertise into an area are > determined by examining the routing table structure (see > Section 11) in accordance with the algorithm described > below. > > " > > > - Any filtering and / or summary is done on the RIB not on the database > it self! > > Personal Note: I much prefer the semantics story being told. if you wish to > follow someone all your professorial life you can take the easy way and > learn configurations and some of the basic or even advanced designs and you > will do fine in your work, however if you wish to be followed upon and be > that one that people turn to for answers, you MUST know and understand the > semantics even if it mean that you need to waist more time and effort. > > > > > On Thu, Jan 3, 2013 at 11:46 AM, Brian McGahan <bmcgahan_at_ine.com> wrote: > >> If you want to continue this as a technical discussion that's fine, just >> don't freak out again after reading my response ;) >> >> You said: >> >>> What if in area 1 there are some LSA type-1 and type-2? Can you not >> filter them or summarize them with the "area range" command? >> >> No, you can not. This is a fundamentally incorrect notion about OSPF. >> First, both LSA 1 and 2 are area local scope. The ABR cannot pass them >> between areas hence there is no filtering or summarization that can affect >> them. Secondly, the *topology* information described by these LSAs is >> automatically summarized by the ABR into LSA 3. The *reachability* >> information is not. >> >> The reachability information described in multiple LSA 3s can summarized >> together with the "area range" command. Additionally the reachability >> information described in LSA 3 can be filtered with either "area range" or >> "area filter-list". >> >> "area range" and "area filter-list" do not affect LSAs 1 or 2, they affect >> LSA 3. You can argue this is semantics if you want, but in binary there are >> only two values, TRUE and FALSE. >> >> >> >> Brian McGahan, CCIE #8593 (R&S/SP/Security) >> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com> >> >> Internetwork Expert, Inc. >> http://www.INE.com >> >> On Jan 3, 2013, at 3:25 AM, "Narbik Kocharians" <narbikk_at_gmail.com<mailto: >> narbikk_at_gmail.com>> wrote: >> >> Unbelievable, >> >> You are saying that LSA Type-2s don't provide reachability information, I >> am saying and showing you that they do provide the subnet mask, you then >> say that you should NOT say LSA filtering because we can not theoretically >> filter LSAs, especially when you are going to take the CCIE lab, let me >> tell you something, they will probably say "LSA Type 3 Filtering" as the >> header, they mention that in every Doc CD i have read, now whose student/s >> will miss out on the terminology? You guys use it because it is "commonly >> used" (Based on Petr) or Cisco says it that way in their DOC-CD, but if I >> say it, you claim that I do not understand basics of OSPF or routing and I >> should be teaching CCNA. >> >> Then, you agree with Paul about my explanation, and then you ask him what >> does that have to do with "Area range" or the other commands, so why is it >> OK with you to use the term "LSA Filtering" and Not anyone else? Check how >> quick you agreed with Paul, and he was basically repeating what I >> mentioned, that tells me that you are agreeing with me but you like to >> argue. I even said at the end of my post "I am not disagreeing with you", >> but I guess it did not click. >> >> Once again, stop doing that. Do you know how to unsubscribe a person from >> a thread? You are very good with google, try it one more time. >> >> On Thu, Jan 3, 2013 at 1:04 AM, Brian McGahan <bmcgahan_at_ine.com<mailto: >> bmcgahan_at_ine.com>> wrote: >> You need to relax Narbik. I'm not sure how you made this leap in the >> discussion, but thanks for once again ruining a potentially helpful and >> intellectual thread on the list. My apologies if I somehow offended you. >> >> >> >> On Jan 3, 2013, at 2:34 AM, "Narbik Kocharians" <narbikk_at_gmail.com<mailto: >> narbikk_at_gmail.com>> wrote: >> >> You are VERY WRONG. Picking words and acting as though you are an attorney >> did not convince me a bit, but your immaturity is what you definitely >> proved here today. You are in a routing loop my friend, we made a full >> circle. >> >> Unsubscribe me from further responses. Paul B the owner of this forum >> forgot to put a disclaimer about people under legal age. >> >> If this continues, I will ignore your replies or comments all together, or >> i will be very rude. >> >> How do you connect this discussion about my students failing because in >> many words they attended my class? What does that have to do with this >> discussion? A student of mine told me that you guys in your volumes say >> "filtering LSA Type 3", so what gives you the right to use the terms that >> you disagree with? >> >> I even commented in your blog, when Petr wrote an article "ospf route >> filtering demystified" right after I released a 10 minute VoD on OSPF >> Filtering, and he admitted in the blog that he uses that same term because >> Cisco uses it in their documentation, but if I use it, I don't know what I >> am talking about? Here incase you forgot: >> http://blog.ine.com/2009/08/17/ospf-route-filtering-demystified/ >> >> As I said before unsubscribe me from this thread. >> >> >> >> >> >> -- >> Narbik Kocharians >> CCSI#30832, CCIE# 12410 (R&S, SP, Security) >> www.MicronicsTraining.com<http://www.micronicstraining.com/> >> Sr. Technical Instructor >> YES! We take Cisco Learning Credits! >> A Cisco Learning Partner >> >> >> Blogs and organic groups at http://www.ccie.net >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html > > > -- > Shiran Guez > MCSE CCNP NCE1 JNCIA-ENT JNCIS-ENT CCIE #20572 > http://cciep3.blogspot.com > http://www.linkedin.com/in/cciep3 > http://twitter.com/cciep3 > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html Blogs and organic groups at http://www.ccie.netReceived on Fri Jan 04 2013 - 01:44:47 ART
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