Re: [OSPF] OSPF WG Last Call for "Hiding Transit-only Networks in OSPF " - <draft-ietf-ospf-prefix-hiding-02.txt>

["Retana, Alvaro" <alvaro.retana at hp.com>]

Shraddha:

Hi!

Yes, you're right...there will be some loss of functionality, but only in the cases where the LSAs are omitted *and* an ASBR is present *and* the forwarding address is already being used.

We will update the draft to indicate the need to not use the forwarding address in those cases, and to discuss the deployment considerations.

Thanks!!

Alvaro.


> -----Original Message-----
> From: ospf-bounces at ietf.org [mailto:ospf-bounces at ietf.org] On Behalf Of
> Shraddha Hegde
> Sent: Thursday, February 09, 2012 11:56 AM
> To: Acee Lindem
> Cc: OSPF List
> Subject: Re: [OSPF] OSPF WG Last Call for "Hiding Transit-only Networks
> in OSPF " - <draft-ietf-ospf-prefix-hiding-02.txt>
> 
> My concern is that we would be introducing a new feature which won't
> work with some existing feature!. Could be a pain for operators who
> already use forwarding address for some optimization and want to use
> network hiding for security.
> 
> Rgds
> Shraddha
> -----Original Message-----
> From: Acee Lindem [mailto:acee.lindem at ericsson.com]
> Sent: Thursday, February 09, 2012 8:43 PM
> To: Shraddha Hegde
> Cc: OSPF List
> Subject: Re: [OSPF] OSPF WG Last Call for "Hiding Transit-only Networks
> in OSPF " - <draft-ietf-ospf-prefix-hiding-02.txt>
> 
> Hi Shraddha,
> 
> You raise a very good point.
> 
> On Feb 9, 2012, at 4:33 AM, Shraddha Hegde wrote:
> 
> > In case of p2mp networks, type 3 links used to describe the interface
> > address is omitted to hide the network.
> >
> > This can cause problems in the next hop calculation in certain cases
> and in my opinion it is better to avoid installing a certain route  (as
> done in case of broadcast networks in this draft) rather than
> completely omitting it.
> >
> > Consider a scenario when p2mp interfaces are configured in the NSSA
> area.
> >
> > A---------B
> >     |
> >     ------C
> >
> > A,B and C are connected over a p2mp network configured in NSSA area.
> > B & C are ASBRs importing external routes. B & C will have to include
> forwarding address corresponding to interface address when they
> advertise external LSA to A.
> > We cannot hide the p2mp network in the above scenario as type 3 stub-
> links are completely omitted, we cannot resolve the forwarding address
> for the external LSAs originated by B & C.
> 
> I think there should just be a general statement that a forwarding
> address MUST not be advertised when prefix-hiding is configured on the
> next-hop interface. However, we'll see what the authors have to say.
> 
> 
> Thanks,
> Acee
> 
> 
> 
> >
> > Rgds
> > Shraddha
> >
> > -----Original Message-----
> > From: ospf-bounces at ietf.org [mailto:ospf-bounces at ietf.org] On Behalf
> > Of Acee Lindem
> > Sent: Wednesday, February 08, 2012 10:37 PM
> > Cc: OSPF List
> > Subject: [OSPF] OSPF WG Last Call for "Hiding Transit-only Networks
> in
> > OSPF " - <draft-ietf-ospf-prefix-hiding-02.txt>
> >
> > As I have heard no objections, I'm beginning the 2 week OSPF Working
> Group last call for draft-ietf-ospf-prefix-hiding-02.txt.
> > Please review the draft and post your last call comments prior to
> 12:00 AM PDT on February 23nd, 2012.
> > Here is a URL for your convenience:
> >
> > http://www.ietf.org/id/draft-ietf-ospf-prefix-hiding-02.txt
> >
> > Thanks,
> > Acee
> >
> > On Jan 26, 2012, at 11:19 AM, Acee Lindem wrote:
> >
> >> As WG co-chair, I have reviewed this document and believe it is
> ready for OSPF WG last call. Any other opinions?
> >> There is at least one implementation. Here is a URL for you
> convenience:
> >>
> >>  http://www.ietf.org/id/draft-ietf-ospf-prefix-hiding-01.txt
> >>
> >> There is an IPR disclosure on this draft:
> >>
> >>  http://datatracker.ietf.org/ipr/1423/
> >>
> >> I will start WG last call next week if I don't hear any objections.
> >>
> >> Thanks,
> >> Acee
> >>
> >>
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