Re: [Softwires] Re: WG LC Problem Statement (Pekka Savola Comments)
"Spencer Dawkins" <spencer@mcsr-labs.org> Tue, 03 January 2006 17:57 UTC
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From: Spencer Dawkins <spencer@mcsr-labs.org>
To: softwires@ietf.org
References: <Pine.LNX.4.64.0512220848380.8766@netcore.fi>
Subject: Re: [Softwires] Re: WG LC Problem Statement (Pekka Savola Comments)
Date: Tue, 03 Jan 2006 11:55:55 -0600
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Still working through the comment backlog... Spencer > Hi, > > I've re-read the problem statement. Below are also those comments for the > earlier version that didn't seem to be addressed but still seem applicable > [1]). > > I do not think the problem statement can go forward in its current form. > It clearly has not been read enough even by the co-authors as it has a > number of typos, procedural omissions (failing ID-nits and so on) etc. > But I'm hopeful that these and the couple of substantial issues could be > fixed in one or two revisions and the doc could go forward around the > January timeframe. > > substantial > ----------- > > [1] -- the issue with the assumption that the connected islands have just > one address family (instead of being dual-stack) is serious and requires > significant rewording. The currently described problem is not the one > described by CERNET. The rest of the comments are at the end of this > mail. Just so I'm sure I'm following you, we're still assuming that only one AF is being tunneled, right? > 3.2. Network Address Translation (NAT) and Port Address Translation > (PAT) > ... > There is no requirement to be able to "autodetect" NAT or PAT > presence during softwire setup. > > ==> I do not agree with this statement without further qualifiers. The > softwire setup needs to work by default through a NAT, and the statement > above does not really address that point. Suggest replacing with: > > Establishing a softwire through NAT or PAT must work by default. > However, there is no requirement for explicitly "autodetect" > NAT or PAT presence during softwire setup. > > I.e., unless the solution provides autodetection, it must be chosen in a > manner that can traverse NAT/PAT. I think that's a hard requirement. I agree with this change. If others do not agree, please let me know (and we can discuss it). > 3.7. Softwire Concentrator Discovery > > When the initiator of the softwire is a CPE, the IP address or DNS > hostname of the softwire concentrator must be known. The simplest > way for this to be known by the CPE is for it to be configured by the > user, or by the provider of the CPE in advance. Alternatively, an > automated discovery phase may be run in order to return the IP > address(s), or hostname(s) of the concentrator. The details of this > discovery problem are outside the scope of this document. > > ==> The first "When the initiator of the softwire is a CPE," is not true > and should be removed or reworded. The same text applies (roughly) in all > cases 1-3, though configuration is more difficult if the initiator is not > CPE. The text needs to be generalized. I agree with this change and plan to simply remove the identified phrase. > It should be noted that according to reports the islands do not want > to achieve network connectivity via tunneled Layer 2 mechanisms but, > as distinct Layer 3 or MPLS routers. This clearly helps scaling and > Layer 2 discovery performance issues. It also prevents having to > have fully meshed point to point Layer 2 connectivity between the > nodes in differing islands as Layer 2 technology choice must be > preserved. > > ==> while one network might want to use Layer 3 mechanism, I do not think > Layer 2 should be ruled out as it's a more generic solution. We should > provide a solution for that as well. I agree with the thought but am having a hard time reading this into the Softwires charter (which seems pretty clearly focused on Layer 3). David/Alain, could you express an opinion here? > semi-editorial > -------------- > > ==> in hub and spoke case 2 and case 3, isn't HGW typically v4-only > (otherwise we'd be looking at case 1?), like follows: > > +-------+ +-------------+ +--------+ > | | | Softwire | | IPv6 | > +-----+ +-----+ | Pv4 |---| concentrator|--| Network| > |Host |--| HGW |---| | +-------------+ +--------+ > +-----+ +-----+ |Network| > +-------+ > _ _ _ _ _ _ _ _ _ _ _ _ > ()_ _ _ _ _ _ _ _ _ _ _ _() > "softwire" > |-------|-------------------||-------------------------| > Dual IPv4 only IPv6 or dual stack > stack > > (however, it'd be possible for HGW be dual-stack but just not support > setting up softwires..) I understand the diagram and think I understand what to do with the document. Are you looking for more than a note that says "However ... " on your parenthetical comment? > 3.4. Static Prefix Delegation > > ==> split the first paragraph in 2 or 3. Agree... > procedural issues > ----------------- Agree with all the following... > ==> it'd be appropriate to acknowledge the earlier problem statement work > in this space -- at least draft-palet-v6tc-goals-tunneling-00, which > includes references to even prior art. > > ==> a "null" IANA considerations section is needed. > > ==> the front page lists 6 authors. This is more than the maximum limit > (5). I'd suggest just putting the editor on the front page. > > 7. References > > ==> need splitting to norm/informative > > ==> the referred docs (e.g., Steve Bellovin's IPsec recommendations) need > to be added as explicit recommendations here. > > editorial > --------- Agree with these. > ==> spell out the terms when used the first time (at least, "ISP") > > multicast trafic. They are also assumed to be non-ephemeral in > nature thus, they are peristent or long-lived. Last, the setup > > ==> s/trafic/traffic/ > ==> s/peristent/persistent/ > > setup time of the CPE/Address Family Boundry Router (AFBR) > > ==> s/Boundry/Boundary/ > ==> missing "." at the end. > > Section 5). The primary difference between these two problems are > how many connections and associated routes are managed by each IPv4 > > ==> s/are/is/ > > number of well connected hubs and then deserve smaller airports > > ==> s/deserve/serve/ > > There are three cases refer to Hubs and Spokes problem > which are shown in Diagram 1. > > ==> cannot parse "are three cases refer". Missing "that" ? > > contentrator. An ISP may deploy several concentrators (for example > > ==> s/content/concent/ > > a keepalive mechanism MUST be define. Such a mechanism is also > > ==> s/define/defined/ > > Other OAM needed features include: > > ==> s/OAM needed/needed OAM/ > > - Path failure detection) > > ==> remove ")" ? (both in section 3 and 4) > > differing address family type. For an example, See Figure 1. Note > > ==> it's figure 2. > > It should also be noted that the mesh problem can be treat as a > > ==> s/treat/treated/ > > In contrast with the hub and spoke problem, routers are advertizing > routers for relatively large islands, and never a single user so > there is no "user authentication" necessary. > > ==> "routers are advertizing routers" and ", and never a single user" -- > reword this sentence. > > IPv6/IPv4,IPv4/IPv6 and overlapping address space as defined in the > > ==> s/,/, / > > > ============== > [[ earlier comments that still seem to be valid ]] > > 3.8. Scaling > > In a hub and spoke model, an ISP MUST scale the solution to millions > of softwire inititators by adding more hubs (i.e. softwire > concentrator). > > ==> s/MUST scale/must be able to scale/ (we cannot give upper-case > requirements on what the ISPs do, and even so, it's a bit inappropriate to > use upper-case keywords in a requirements document) Agree. > - End-point failure detection (must be encapsulated w/in the tunnel > in the transmitting direction Agree... > ==> please clarify what you mean after '(', it's not clear. > > Reference Diagram > > ._._._._ ._._._._ > | | | | > | V4 | | V4 | > |access | |access | > |island | |island | > ._._._._ ._._._._ > > ==> I don't think this was the case we were talking about. Shouldn't all > the islands be dual-stack? This is pretty important consideration -- the > key point emerges when an island with protocol X would like talk to an > island with protocol Y. (where an island could be the rest of the internet > as well). Agree - otherwise we're talking protocol translation, not tunneling. > The AFBR's are the only devices in the network that must be able to > perform dual-stack operations and setup and encapsulate softwires in > a mesh to the other islands. > > ==> s/network/ISP's network/ -- the CPEs should obviously be dual-stack, > right, so those could set up tunnels if they wished to. Agree. > It should be noted that according to reports the islands do not want > to achieve network connectivity via tunneled Layer 2 mechanisms but, > as distinct Layer 3 or MPLS routers. This clearly helps scaling and > Layer 2 discovery performance issues. > > ==> it isn't clear enough what this point means. Agree, and I'm not sure whether this even needs to be mentioned - especially if it morphs into a "describe the Layer 2/Layer 3 tradeoffs" paragraph. Our charter is for a Layer 3 solution - do we need to say more than that? _______________________________________________ Softwires mailing list Softwires@ietf.org https://www1.ietf.org/mailman/listinfo/softwires
- [Softwires] WG LC Problem Statement David Ward
- RE: [Softwires] WG LC Problem Statement BAUDOT Alain RD-CORE-CAE
- [Softwires] Re: WG LC Problem Statement Pekka Savola
- Re: [Softwires] Re: WG LC Problem Statement JORDI PALET MARTINEZ
- Re: [Softwires] Re: WG LC Problem Statement JORDI PALET MARTINEZ
- Re: [Softwires] WG LC Problem Statement Francis Dupont
- Re: [Softwires] WG LC Problem Statement Francis Dupont
- Re: [Softwires] WG LC Problem Statement (Alain Ba… Spencer Dawkins
- Re: [Softwires] WG LC Problem Statement JORDI PALET MARTINEZ
- Re: [Softwires] WG LC Problem Statement JORDI PALET MARTINEZ
- Re: [Softwires] WG LC Problem Statement Francis Dupont
- Re: [Softwires] WG LC Problem Statement Francis Dupont
- Re: [Softwires] WG LC Problem Statement JORDI PALET MARTINEZ
- Re: [Softwires] Re: WG LC Problem Statement (Pekk… Spencer Dawkins
- Re: [Softwires] WG LC Problem Statement (Francis … Spencer Dawkins
- Re: [Softwires] Re: WG LC Problem Statement (Pekk… Pekka Savola
- Re: [Softwires] WG LC Problem Statement (Francis … Spencer Dawkins