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Re: [Lsr] OSPF TE Link Local TLV

"Acee Lindem (acee)" <acee@cisco.com> Tue, 05 February 2019 18:29 UTC

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From: "Acee Lindem (acee)" <acee@cisco.com>
To: Okonnikov Alexander <alexander.okonnikov@gmail.com>, "ccamp@ietf.org" <ccamp@ietf.org>, "lsr@ietf.org" <lsr@ietf.org>
Thread-Topic: [Lsr] OSPF TE Link Local TLV
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Date: Tue, 05 Feb 2019 18:29:33 +0000
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Subject: Re: [Lsr] OSPF TE Link Local TLV
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Hi Alex,

From: Alexander Okonnikov <alexander.okonnikov@gmail.com>
Date: Tuesday, February 5, 2019 at 12:59 PM
To: Acee Lindem <acee@cisco.com>, "ccamp@ietf.org" <ccamp@ietf.org>, "lsr@ietf.org" <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>
Отправлено: вторник, февраля 5, 2019 20:21
Кому: Alexander Okonnikov; ccamp@ietf.org; lsr@ietf.org
Тема: Re: [Lsr] OSPF TE Link Local TLV

Hi Alex,


From: Lsr <lsr-bounces@ietf.org> on behalf of Alexander Okonnikov <alexander.okonnikov@gmail.com>
Date: Tuesday, February 5, 2019 at 7:48 AM
To: "ccamp@ietf.org" <ccamp@ietf.org>, "lsr@ietf.org" <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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