Re: [Lsr] OSPF TE Link Local TLV

Peter Psenak <ppsenak@cisco.com> Wed, 06 February 2019 09:02 UTC

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To: Alexander Okonnikov <alexander.okonnikov@gmail.com>, "Acee Lindem (acee)" <acee@cisco.com>
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From: Peter Psenak <ppsenak@cisco.com>
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Subject: Re: [Lsr] OSPF TE Link Local TLV
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Hi Alex,

I believe you are right in saying that the RFC 4203 defined Link Local 
Identifier sub-TLV of the Link Local TLV, but did not do any IANA 
registration for it.

thanks,
Peter


On 05/02/2019 20:40 , Alexander Okonnikov wrote:
> Hi Acee,
>
> Yes, RFC 8510 provides alternative mechanism, but link identifier
> discovery mechanism via link-local TE LSA is still valid. Hence, I think
> that early mentioned issues need to be addressed.
>
> Thank you!
>
>> 5 февр. 2019 г., в 21:29, Acee Lindem (acee) <acee@cisco.com
>> <mailto:acee@cisco.com>> написал(а):
>>
>> Hi Alex,
>>
>> *From: *Alexander Okonnikov <alexander.okonnikov@gmail.com
>> <mailto:alexander.okonnikov@gmail.com>>
>> *Date: *Tuesday, February 5, 2019 at 12:59 PM
>> *To: *Acee Lindem <acee@cisco.com <mailto:acee@cisco.com>>,
>> "ccamp@ietf.org <mailto:ccamp@ietf.org>" <ccamp@ietf.org
>> <mailto:ccamp@ietf.org>>, "lsr@ietf.org <mailto:lsr@ietf.org>"
>> <lsr@ietf.org <mailto:lsr@ietf.org>>
>> *Subject: *Re: [Lsr] OSPF TE Link Local TLV
>>
>> Hi Acee,
>>
>> Per my understanding Link Local/Remote ID Sub-TLV is to be conveyed in
>> area-scope LSA to uniquely identify link between pair of routers. For
>> link-local scope another Sub-TLV was introduced, for discovery of link
>> IDs by two neighbors.
>>
>> The context is completely different –
>> see https://www.rfc-editor.org/rfc/rfc8510.txt
>>
>> May be, it is possible to reuse Link Local/Remote ID Sub-TLV (with
>> Remote ID = 0) of Link TLV in link-local scope LSA, but the RFC
>> follows another approach - to use another Sub-TLV and another TLV. I
>> am not sure that we needed dedicated top-level TLV, though idea to use
>> separate Sub-TLV seems to be reasonable.
>>
>> It is also possible to use a sledge hammer to crack a nut….
>>
>> Acee
>>
>> Thank you!
>>
>> Best regards,
>> Alexander Okonnikov
>>
>> ------------------------------------------------------------------------
>> *От:* Acee Lindem (acee) <acee@cisco.com <mailto:acee@cisco.com>>
>> *Отправлено:* вторник, февраля 5, 2019 20:21
>> *Кому:* Alexander Okonnikov; ccamp@ietf.org
>> <mailto:ccamp@ietf.org>; lsr@ietf.org <mailto:lsr@ietf.org>
>> *Тема:* Re: [Lsr] OSPF TE Link Local TLV
>>
>> Hi Alex,
>>
>>
>> *From: *Lsr <lsr-bounces@ietf.org <mailto:lsr-bounces@ietf.org>> on
>> behalf of Alexander Okonnikov <alexander.okonnikov@gmail.com
>> <mailto:alexander.okonnikov@gmail.com>>
>> *Date: *Tuesday, February 5, 2019 at 7:48 AM
>> *To: *"ccamp@ietf.org <mailto:ccamp@ietf.org>" <ccamp@ietf.org
>> <mailto:ccamp@ietf.org>>, "lsr@ietf.org <mailto:lsr@ietf.org>"
>> <lsr@ietf.org <mailto:lsr@ietf.org>>
>> *Subject: *[Lsr] OSPF TE Link Local TLV
>>
>> Hi,
>>
>> I have question regarding RFC 4203, Section 3. That section introduces
>> top-level TLV type 4 (Link Local TLV) and, at the same time, describes
>> Link Local Identifier TLV. I guess that latter in fact is Sub-TLV of
>> Link Local TLV. Also, IANA Considerations section doesn't mention that
>> Sub-TLV, but only introduction of Link Local TLV. IANA has no
>> corresponding registry  - "Types for Sub-TLVs of Link Local TLV (Value
>> 4)".
>>
>> I believe this example is actually wrong and section 3 should refer to
>> the top-level Link TLV (value 2) defined in RFC 3630. The Link Local
>> Identifier is the one advertised in Link Local/Remote Identifiers
>> Sub-TLV (type 11) defined in RFC 4203 section 1.1.
>>
>> Hope this helps,
>> Acee
>>
>> Thanks in advance.
>>
>> Best regards,
>> Alexander Okonnikov
>
>
>
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