Re: [OSPF] OSPFv3 LSA Extendibility - draft-acee-ospfv3-lsa-extend-00.txt

Hi guys,

Does bellow looks like what you are saying ?

Two mode of operation:

RFC5340Compatibility is off (default)

In this mode router originates only new types of LSAs.
Router consider only new type of LSAs from other routers.
Router does not establish adjacencies with old routers. 

RFC5340Compatibility is on (non-default; need to be configured during transition). 

In this mode router originates both old and new types of LSA.
Router prefers new type of LSA for SPF calculation.
Router establish adjacencies with both types for routers.

Old format router LSA  has ExtendedFormatCapable flag set for the case when corresponded new format LSA stuck somewhere
When all old type  LSAs in the router database have ExtendedFormatCapable flag, router flushes self-originated LSA in old format.
The flag ExtendedFormatCapable  should be propagated across area borders similar to  OSPF demand circuit-like.

Thank you,
Mike

> -----Original Message-----
> From: ospf-bounces@ietf.org [mailto:ospf-bounces@ietf.org] On Behalf Of
> Peter Psenak (ppsenak)
> Sent: Friday, June 28, 2013 6:29 AM
> To: Acee Lindem
> Cc: OSPF@ietf.org
> Subject: Re: [OSPF] OSPFv3 LSA Extendibility - draft-acee-ospfv3-lsa-extend-
> 00.txt
> 
> Hi Acee,
> 
> On 28.6.2013 11:44, Acee Lindem wrote:
> > Hi Anton, Peter,
> > If I were to be convinced that #2 is the way to go, I like making it explicit
> configurations and only applicable to service provider and large enterprise
> deployments. That way, OSPFv3 implementations specifically for the
> homenet environments could omit it.
> 
> I'm fine with the config based approach.
> 
> thanks,
> Peter
> 
> > Thanks,
> > Acee
> > On Jun 28, 2013, at 4:00 AM, Anton Smirnov wrote:
> >
> >>    Hi Acee,
> >>    while I appreciate developer's simplicity of option 1 this approach is good
> only for greenfield deployment. For any existing sizable OSPFv3 network its
> migration limitation may become an insurmountable obstacle.
> >>    My preference is combination of options: start migration as option 2 and
> when migration is completed lock on 1.
> >>    Benefits are that migration is possible; LSDB is doubled only for period of
> migration; and once migration is completed there is no need to worry about
> dynamics of old-style router entering the domain.
> >>    Downside is relative complexity of implementation but that's the price
> to pay for simplicity of OSPFv3. BTW, entering and exiting migration may be
> manual (via configuration), so this mixed approach may be simpler to
> implement than 'pure' option 3.
> >>    Said all that, individual products targeting greenfield deployment
> scenario may skip implementation of migration. Say, homenet may require
> support of extended LSAs from day 1. That would mean that homenet
> products will not be deployable in existing old-style-LSA networks - but that
> probably is not the intent anyway.
> >>
> >> Anton
> >>
> >>
> >> On 06/27/2013 10:18 PM, Acee Lindem wrote:
> >>> I don't think there is much disagreement that we need a direct way
> >>> to extend the base OSPFv3 LSAs and I will be presenting this draft
> >>> at IETF
> >>> 87 in Berlin. Where there appears to be some amount of disagreement
> >>> is in the backward compatibility mechanisms. There are basically 3
> >>> options (as well as subtle variants)
> >>>
> >>>
> >>>          1. The approach in the draft, only allow adjacencies
> >>> between routers supporting the extended encodings. Backward
> >>> compatibility would have to be provided with separate instances and
> topology.
> >>>
> >>>         2. Both the current and extended versions of the LSAs are
> >>> originated as long as there are routers not supporting the new
> >>> extended encodings at the respective flooding scope. This was the
> >>> approach taken in "Multi-toplogy routing in OSPFv3 (MT-OSPFV3)",
> >>> draft-ietf-ospf-mt-ospfv3-04.txt. However, it has the undesirable
> >>> property of roughly doubling the size of the LSDB.
> >>>
> >>>        3. Switch to the extended format only after all the routers
> >>> at the flooding scope support it. Use OSPF demand circuit-like (RFC
> >>> 1793) signaling to determine whether or not all routers in the
> >>> flooding scope support the new format. The only potential problem
> >>> with this approach is a dynamics when a router not supporting the
> >>> extended format successively leaves and enters the routing domain.
> >>>
> >>> What is the WG preference? I'm still in favor of the approach in the
> >>> draft (#1) given the simplicity and stability properties. What we'd
> >>> lose in slowed deployment would be more than made up
> standardization
> >>> and availability. Also, it would satisfy the homenet requirements we
> >>> desperately need to satisfy.
> >>>
> >>> Thanks,
> >>> Acee
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> OSPF mailing list
> >>> OSPF@ietf.org
> >>> https://www.ietf.org/mailman/listinfo/ospf
> >>>
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> >> OSPF@ietf.org
> >> https://www.ietf.org/mailman/listinfo/ospf
> >
> >
> >
> 
> 
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