Re: Type-7 to Type-5 translation issue

[Santosh Esale <s.esale at GMAIL.COM>]

Hi Acee,
            U mean i should check whether the ASBR path is via type-5
capable area, and if its not USE NSSA external lsa for calculation and
do the type-7 to type-5 conversion immediately.

I do agree with this...but we are doubling the LSP database size, how
to slove it?

Thanks
Santosh

On 5/16/05, Acee Lindem <acee at cisco.com> wrote:
> Hi Santosh,
> 
> Whether or not R1 purges its AS-external-LSAs prior to area 1 being
> coverted from a regular area to an NSSA is implementation specific.
> However, the
> timing of the conversion may be such that R1 is unable to purge them
> from the
> OSPF routing domain. In all cases, R1 should immediately originate
> NSSA-LSAs
> (type-7s) for redistributed routes. When R2 computes its external/NSSA
> routes
> it should not use R1's AS-external-LSA since its path to the ASBR is not
> through
> a regular area (see section 2.5 in RFC 3101).
> 
> Hope this helps,
> Acee
> 
> Santosh Esale wrote:
> 
> >Hi guys,
> >           Mine topology is as below-
> >
> >R1----Area 1 ------R2--------Backbone Area------R3
> >
> >Initially Area 1 was type-5 capabale area and i was redistributing RIP
> >routes into area 1 on R1, so R2 and R3 have type-5 LSAs for all the
> >RIP routes.Now i changed
> >Area 1 to NSSA , So R1 is now orginating type-7 LSAs for all the RIP
> >routes into area 1 with P-bit set.
> >
> >Now mine question is should R2 -
> >
> > 1.     Prefer type 7 LSA over type-5 .
> >Convert type-7 LSA into type-5 LSA  and flood into backbone, which
> >aleardy have  type-5 LSAs for the same netwroks earlier orginated by
> >R1(not yet flushed as it will remain in backbone for MAX AGE)
> >(According to RFC 3101. section 2.5 stp 6 (e) ).
> >
> >Disadvantage: The LSP database size will be doubled till MAX AGE time.
> >Advantage : simplicity
> >
> >2. Prefer type-5 over type-7 .
> >Use type-5 LSA for calculating external routes till type-5 LSAs
> >advertised by R1 exists in backbone(MAX Age) , and once type is
> >flushed because of MAX age , USE type -7 now to calculate external
> >routes , and translate at this point from type-7 to type-5(RFC 1587
> >3.5 step 5)
> >
> >Advantage : LSP database size is small.
> >Disadvantage: bit complex,but not much.
> >
> >3. or its Implementations Specific.
> >
> >Thanks in Advance
> >
> >
> >
> >
> 


-- 
Santosh Esale

Member - Technical Staff

Riverstone Networks India Pvt. Ltd.

Email: sesale at riverstonenet.com