Re: OSPF LSA type 3 filtering

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
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