Re: [Ospf-wireless-design] Design team outbrief (draft slides) posted
Emmanuel Baccelli <Emmanuel.Baccelli@inria.fr> Mon, 07 November 2005 17:46 UTC
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Date: Mon, 07 Nov 2005 18:45:07 +0100
From: Emmanuel Baccelli <Emmanuel.Baccelli@inria.fr>
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Subject: Re: [Ospf-wireless-design] Design team outbrief (draft slides) posted
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I think there is something rather confusing in the latest discussions: the use of the term adjacency, especially when compared to its traditional meaning in OSPF. For example, some simulation results tend to show that the MDR approach features a reduced number of adjacencies without featuring any route stretching -- if "min-hop" LSAs a used. However, this supposes that routing is not only done over adjacencies (indeed, if routing was only done over adjacencies, the MDR approach leads to more than 50% route stretching in most cases). This is thus very confusing, since in traditional OSPF routing is supposed to happen only over adjacencies. So there is here at least a vocabulary issue, that needs to be clarified in my opinion. Emmanuel Richard Ogier wrote: >> Emmanuel Baccelli stated that MPR flooding offers better properties >> than CDS flooding, with at least as good topology reduction >> capabilities, and better routing stretch performance > > > After further consideration, I partly agree with the above statement > depending on how it is interpreted. > The part about "better route stretch performance" is true if we are > talking only about *flooding* and not *routing* (since routing can > occur along non-adjacencies). Min-hop routing can be achieved either > with MPRs or with the min-cost LSAs described in the MDR draft. > > The part about "good topology reduction capabilities" depends on how > adjacencies are defined. (By topology reduction I am talking about > adjacencies, keeping in mind that LSAs can also include non-adjacent > neighbors.) In our simulations, Phil and I showed that this > is certainly not true if each node forms an adjacency with each of > its MPRs and MPR selectors, and Emmanuel has agreed with this: > >> On the other hand using >> MPR/MPRselector adjacencies does yield more adjacencies, >> but no route stretching whatsoever. > > > > If adjacencies are defined in another way, then the method needs > to be specified. One possible way (which I plan to investigate by > modifying OSPF-MDR) is to select the CDS/MDRs by pruning MPRs > and then defining adjacencies as in the MDR draft, but Emmanuel > did not specify such a method. > > Richard > > > > > _______________________________________________ > Ospf-wireless-design mailing list > Ospf-wireless-design@lists.ietf.org > https://www1.ietf.org/mailman/listinfo/ospf-wireless-design > > _______________________________________________ Ospf-wireless-design mailing list Ospf-wireless-design@lists.ietf.org https://www1.ietf.org/mailman/listinfo/ospf-wireless-design
- [Ospf-wireless-design] Design team outbrief (draf… Henderson, Thomas R
- Re: [Ospf-wireless-design] Design team outbrief (… Richard Ogier
- RE: [Ospf-wireless-design] Design team outbrief (… Henderson, Thomas R
- Re: [Ospf-wireless-design] Design team outbrief (… Richard Ogier
- Re: [Ospf-wireless-design] Design team outbrief (… Richard Ogier
- Re: [Ospf-wireless-design] Design team outbrief (… Richard Ogier
- Re: [Ospf-wireless-design] Design team outbrief (… Emmanuel Baccelli
- RE: [Ospf-wireless-design] Design team outbrief (… Spagnolo, Phillip A