Internet DRAFT - draft-gong-lsr-lldp-interface-id
draft-gong-lsr-lldp-interface-id
Network Working Group L. Gong
Internet Draft China Mobile
Intended status: Standards Track C. Lin
Expires: August 24, 2024 M. Chen
New H3C Technologies
February 26, 2024
IGP Logical Link Discovery Protocol (LLDP) Interface Identifier
Discovery
draft-gong-lsr-lldp-interface-id-00
Abstract
This document describes how OSPF and IS-IS would use LLDP to
discover the identifier of remote interface. The typical
applications are the topology discovery of Layer 2 bundle members
and unnumbered interfaces.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
This Internet-Draft will expire on August 24, 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
Gong, et al. Expire August 24, 2024 [Page 1]
Internet-Draft LLDP Interface ID Discovery February 2024
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with
respect to this document. Code Components extracted from this
document must include Simplified BSD License text as described in
Section 4.e of the Trust Legal Provisions and are provided without
warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction...................................................2
1.1. Requirements Language.....................................2
2. Use Cases......................................................3
2.1. Topology Discovery of Layer 2 Bundle Members..............3
2.1.1. Existing Solution....................................3
2.1.2. Proposed Solution....................................4
2.2. Topology Discovery of Unnumbered Interfaces...............5
3. LLDP Extension.................................................5
4. BGP-LS Extension...............................................6
5. Security Considerations........................................6
6. IANA Considerations............................................6
7. References.....................................................6
7.1. Normative References......................................6
7.2. Informational References..................................7
Authors' Addresses................................................7
1. Introduction
The Link Layer Discovery Protocol (LLDP) [802.1AB] is a standard
link layer protocol that allows network devices to discover
neighbors and exchange information.
Using the LLDP, a device can get its neighbor's MAC address or
interface name through the Port ID TLV. However, in some scenarios,
there are requirements to get the interface identifier of the
neighbor. The typical applications are the topology discovery of
Layer 2 bundle members and unnumbered interfaces.
This document specifies the LLDP IETF Organizationally Specific TLV
that carries the interface identifier for OSPF and IS-IS protocols.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
Gong, et al. Expires August 24, 2024 [Page 2]
Internet-Draft LLDP Interface ID Discovery February 2024
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Use Cases
2.1. Topology Discovery of Layer 2 Bundle Members
BGP-LS [RFC7752] is widely used for collection of topology
information from IGP. In networks where L2 bundle is deployed, the
connectivity relationships between bundle members are required to be
collected by the controller, for traffic engineering purposes.
When advertising the L2 bundles in OSPF [RFC9356] and IS-IS
[RFC8668], each L2 bundle member can carry an OSPF Local/Remote
Interface ID TLV or an IS-IS Link Local/Remote Identifiers TLV,
which contains both the IDs of local interface and remote interface.
However, IGP has no means of automatically obtaining the remote
interface ID.
An existing solution is described in Section 2.1.1. The LLDP is used
to exchange interface names between L2 bundle members. In addition
to BGP-LS, the controller collects interface and LLDP information
through NETCONF.
Section 2.1.2 proposes a new solution. The LLDP is extended to
exchange interface IDs between L2 bundle members and advertises the
<Local Interface ID, Remote Interface ID> pairs into IGP and BGP-LS.
2.1.1. Existing Solution
The local interface IDs of L2 bundle members are advertised in IGP,
and collected by the controller using BGP-LS.
The L2 bundle members run LLDP to exchange the interface name with
neighbors. The controller uses NETCONF to collect the pairing
relationships between the interface names of member links, along
with the correspondence between interface names and interface IDs,
from both ends of the L2 bundle.
Combining the information collected from BGP-LS and NETCONF, the
controller can figure out the topology of L2 bundle members.
Gong, et al. Expires August 24, 2024 [Page 3]
Internet-Draft LLDP Interface ID Discovery February 2024
+----------+ BGP-LS
|Controller|<--------------+
+----------+ +
^ ^ |
NETCONF | | NETCONF |
+----------+ +----------+ |
| | |
| | |
+----+ L2-Bundle +----+ +----+
| | /---member 1---\ | | | |
| R1 +-----member 2-----+ R2 +---+ R3 +
| | \---member 3---/ | | | |
+----+ +----+ +----+
^ ^
| |
+-------- LLDP --------+
interface name of member links
Figure 1
Information collected through BGP-LS:
o R3: Local Interface ID of L2-bundle Members (originally
advertised by R1 and R2)
Information collected through NETCONF:
o R1: Local Interface ID & Name of L2-bundle Members
o R2: Local Interface ID & Name of L2-bundle Members
o LLDP (from R1/R2): <Local Interface Name, Remote Interface Name>
Pairs
2.1.2. Proposed Solution
The L2 bundle members run LLDP to exchange the interface ID with
neighbors using the new-defined TLV in Section 3.
The pairing relationships between the interface IDs of member links
are advertised in IGP. In OSPF, each L2 bundle member carries an
OSPF Local/Remote Interface ID TLV. In IS-IS, each L2 bundle member
carries an IS-IS Link Local/Remote Identifiers TLV.
The controller only needs to collect the topology information using
BGP-LS from one node in the IGP area.
Gong, et al. Expires August 24, 2024 [Page 4]
Internet-Draft LLDP Interface ID Discovery February 2024
+----------+ BGP-LS
|Controller|<--------------+
+----------+ +
|
|
|
|
|
+----+ L2-Bundle +----+ +----+
| | /---member 1---\ | | | |
| R1 +-----member 2-----+ R2 +---+ R3 +
| | \---member 3---/ | | | |
+----+ +----+ +----+
^ ^
| |
+-------- LLDP --------+
interface ID of member links
Figure 1
Information collected through BGP-LS:
o R3: <Local Interface ID, Remote Interface ID> Pairs of L2-bundle
Members (originally advertised by R1 and R2)
2.2. Topology Discovery of Unnumbered Interfaces
An unnumbered interface borrows the IP address from other
interfaces. When unnumbered interfaces are deployed, multiple
interfaces of a router can share the same IP addresses. Based on the
information collected by BGP-LS, the controller cannot figure out
the connectivity relationships between unnumbered interfaces only
according to the IP addresses.
Similar with the solution in Section 2.1.2, unnumbered interfaces
can run LLDP to exchange the interface ID and then advertise the
<Local Interface ID, Remote Interface ID> pairs in IGP.
3. LLDP Extension
LLDP TLVs that belong to an organization are identified by the
inclusion of the organization's OUI (Organizationally Unique
Identifier) and an organizationally defined subtype in the initial
octets of the information field.
This document defines a new IETF specific subtype, interface ID,
under the IANA OUI. The LLDP IETF Organizationally Specific TLV of
Gong, et al. Expires August 24, 2024 [Page 5]
Internet-Draft LLDP Interface ID Discovery February 2024
the new-defined subtype carries the local identifier of interface,
which has the following 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 (127) | Length (8) | OUI (3 Octets) 00-00-5E |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OUI Continued | Subtype (TBD) | Interface ID (4 Octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID Continued |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: IETF Organizationally Specific TLV type value, 127.
o Length: Length of the remainder of the TLV, 8.
o OUI: Organizationally Unique Identifier. For IETF use, this field
is the IANA OUI (00-00-5E) as specified in RFC 7042.
o Subtype: Subtype for interface ID, TBD.
o Interface ID: Local identifier of interface, 4 octets.
4. BGP-LS Extension
This document extends BGP-LS to allow L2 Bundle Member Attributes
TLV [RFC9085] to carry Link Local/Remote Identifiers TLV [RFC9552]
as its sub-TLV.
5. Security Considerations
TBD.
6. IANA Considerations
TBD.
7. References
7.1. Normative References
[802.1AB] "IEEE Standard for Local and metropolitan area networks-
Station and Media Access Control Connectivity Discovery",
IEEE Std 802.1AB-2016, 29 January 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Gong, et al. Expires August 24, 2024 [Page 6]
Internet-Draft LLDP Interface ID Discovery February 2024
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, May 2017
[RFC9085] Previdi, S., Talaulikar, K., Ed., Filsfils, C., Gredler,
H., and M. Chen, "Border Gateway Protocol - Link State
(BGP-LS) Extensions for Segment Routing", RFC 9085, DOI
10.17487/RFC9085, August 2021, <https://www.rfc-
editor.org/info/rfc9085>.
[RFC9552] Talaulikar, K., Ed., "Distribution of Link-State and
Traffic Engineering Information Using BGP", RFC 9552, DOI
10.17487/RFC9552, December 2023, <https://www.rfc-
editor.org/info/rfc9552>.
7.2. Informational References
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016, <https://www.rfc-
editor.org/info/rfc7752>.
[RFC8668] Ginsberg, L., Ed., Bashandy, A., Filsfils, C., Nanduri,
M., and E. Aries, "Advertising Layer 2 Bundle Member Link
Attributes in IS-IS", RFC 8668, DOI 10.17487/RFC8668,
December 2019, <https://www.rfc-editor.org/info/rfc8668>.
[RFC9356] Talaulikar, K. and P. Psenak, "Advertising L2 Bundle
Member Link Attributes in OSPF", RFC 9356, January 2023,
<https://www.rfc-editor.org/info/rfc9356>.
Authors' Addresses
Liyan Gong
China Mobile
China
Email: gongliyan@chinamobile.com
Changwang Lin
New H3C Technologies
China
Email: linchangwang.04414@h3c.com
Gong, et al. Expires August 24, 2024 [Page 7]
Internet-Draft LLDP Interface ID Discovery February 2024
Mengxiao Chen
New H3C Technologies
China
Email: chen.mengxiao@h3c.com
Gong, et al. Expires August 24, 2024 [Page 8]
