--- 1/draft-ietf-mpls-rfc8287-len-clarification-02.txt 2019-08-08 14:13:08.968959106 -0700 +++ 2/draft-ietf-mpls-rfc8287-len-clarification-03.txt 2019-08-08 14:13:08.984959555 -0700 @@ -1,22 +1,22 @@ Network Work group N. Nainar Internet-Draft C. Pignataro Updates: 8287 (if approved) Cisco Systems, Inc. Intended status: Standards Track F. Iqbal -Expires: December 2, 2019 Individual +Expires: February 9, 2020 Individual A. Vainshtein ECI Telecom - May 31, 2019 + August 8, 2019 RFC8287 Sub-TLV Length Clarification - draft-ietf-mpls-rfc8287-len-clarification-02 + draft-ietf-mpls-rfc8287-len-clarification-03 Abstract RFC8287 defines the extensions to MPLS LSP Ping and Traceroute for Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier (SIDs) with an MPLS data plane. RFC8287 proposes 3 Target FEC Stack Sub-TLVs. While the standard defines the format and procedure to handle those Sub-TLVs, it does not sufficiently clarify how the length of the Segment ID Sub-TLVs should be computed to include in the Length field of the Sub-TLVs which may result in interoperability @@ -33,21 +33,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on December 2, 2019. + This Internet-Draft will expire on February 9, 2020. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -90,32 +90,34 @@ 2. Terminology This document uses the terminologies defined in [RFC8402], [RFC8029], [RFC8287] and so the readers are expected to be familiar with the same. 3. Requirements notation The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this - document are to be interpreted as described in [RFC2119] [RFC8174]. + document are to be interpreted as described in [RFC2119] [RFC8174] + when, and only when, they appear in all capitals, as shown here. 4. Length field clarification for Segment ID Sub-TLVs Section 5 of [RFC8287] defines 3 different Segment ID Sub-TLVs that will be included in Target FEC Stack TLV defined in [RFC8029]. The length of each Sub-TLVs MUST be calculated as defined in this section. - The figures in section 5.1, 5.2 and 5.3 of [RFC8287] are replaced by - the below figures in section 4.1, 4.2 and 4.3 respectively. The - updated figures contain explicitly defined length. + The TLVs representation defined in section 5.1, 5.2 and 5.3 of + [RFC8287] are updated to clarify the length calculation as shown in + section 4.1, 4.2 and 4.3 respectively. The updated TLV + representation contain explicitly defined length. 4.1. IPv4 IGP-Prefix Segment ID Sub-TLV The Sub-TLV length for IPv4 IGP-Prefix Segment ID MUST be set to 8 as shown in the below TLV format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type = 34 (IPv4 IGP-Prefix SID)| Length = 8 | @@ -126,49 +128,50 @@ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 4.2. IPv6 IGP-Prefix Segment ID Sub-TLV The Sub-TLV length for IPv6 IGP-Prefix Segment ID MUST be set to 20 as shown in the below TLV format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |Type = 35 (IPv4 IGP-Prefix SID)| Length = 20 | + |Type = 35 (IPv6 IGP-Prefix SID)| Length = 20 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | IPv6 Prefix | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Prefix Length | Protocol | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 4.3. IGP-Adjacency Segment ID Sub-TLV The Sub-TLV length for IGP-Adjacency Segment ID varies depending on the Adjacency Type and Protocol. In any of the allowed combination of Adjacency Type and Protocol, the sub-TLV length MUST be calculated - by including 2 octets of Reserved field. Below is a table that list - the length for different combinations. + by including 2 octets of Reserved field. Table 1 below list the + length for different combinations of Adj.Type and Protocol. - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol | Length for Adj.Type | - + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | Parallel | IPv4 | IPv6 | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | OSPF | 20 | 20 | 44 | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | ISIS | 24 | 24 | 48 | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Any | 20 | 20 | 44 | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Parallel | IPv4 | IPv6 | Unnumbered| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | OSPF | 20 | 20 | 44 | 20 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ISIS | 24 | 24 | 48 | 24 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Any | 20 | 20 | 44 | 20 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + Table 1. IGP-Adjacency SID Length Comparison For example, when the Adj. Type is set to Parallel Adjacency and the Protocol is set to 0, the Sub-TLV will be as below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type = 36 (IGP-Adjacency SID) | Length = 20 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Adj. Type = 1 | Protocol =0 | Reserved | @@ -181,22 +184,22 @@ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receiving Node Identifier (4 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 5. IANA Considerations This document does not introduce any IANA consideration. 6. Security Considerations - This document updates [RFC8287] and does not introduce any security - considerations. + This document updates [RFC8287] and does not introduce any additional + security considerations. 7. Contributors The below individuals contributed to this document: Zafar Ali, Cisco Systems, Inc. 8. Acknowledgement The authors would like to thank Michael Gorokhovsky and Manohar