IDR Working Group Weiguo Hao
Donald Eastlake
Internet Draft Huawei
Intended status: Standard Track Susan Hares
Hickory Hill Consulting
Expires: November 2015 July 28, 2015
Distribution of TRILL Link-State using BGP
draft-hao-idr-ls-trill-02.txt
Abstract
This draft describes a TRILL link state and MAC address reachability
information distribution mechanism using a BGP LS extension.
External components such as an SDN Controller can use the
information for topology visibility, troubleshooting, network
automation, etc.
Status of this Memo
This Internet-Draft is submitted to IETF 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-
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Internet-Drafts are draft documents valid for a maximum of six
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The list of current Internet-Drafts can be accessed at
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Copyright Notice
Copyright (c) 2015 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
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with
respect to this document.
Table of Contents
1. Introduction ................................................ 2
2. Conventions used in this document............................ 3
3. Carrying TRILL Link-State Information in BGP................. 4
3.1. Node Descriptors........................................ 5
3.1.1. IGP Router-ID...................................... 6
3.2. MAC Address Descriptors................................. 6
3.2.1. MAC-Reachability TLV............................... 7
3.3. The BGP-LS Attribute.................................... 7
3.3.1. Node Attribute TLVs................................ 7
3.3.1.1. Node Flag Bits TLV............................ 7
3.3.1.2. Opaque Node Attribute TLV..................... 8
3.3.2. Link Attribute TLVs................................ 9
4. Operational Considerations................................... 9
5. Security Considerations..................................... 10
6. IANA Considerations ........................................ 11
7. References ................................................. 11
7.1. Normative References................................... 11
7.2. Informative References................................. 12
8. Acknowledgments ............................................ 12
1. Introduction
BGP has been extended to distribute IGP link-state and traffic
engineering information to some external components [I-D.ietf-idr-
ls-distribution], such as the PCE and ALTO servers. The information
can be used by these external components to compute a MPLS-TE path
across IGP areas, visualize and abstract network topology, and the
like.
TRILL (Transparent Interconnection of Lots of Links) protocol
[RFC6325] provides a solution for least cost transparent routing in
multi-hop networks with arbitrary topologies and link technologies,
using [IS-IS] [RFC7176] link-state routing and a hop count. TRILL
switches are sometimes called RBridges (Routing Bridges).
The TRILL protocol has been deployed in many data center networks.
Data center automation is a vital step to increase the speed and
agility of business. An SDN controller as an external component
normally can be used to provide centralized control and automation
for the data center network. Making a holistic view of whole network
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topology available to the SDN controller is an important part for
data center network automation and troubleshooting.
+-------------+
| SDN |
--------| Controller |--------
| +-------------+ |
| |
+ + + +
+ +-----------+ +
| |
+--------+ |IP Network | +--------+
| | +----+ +----+ | |
+---+ +---+ | | | | | | | | +---+ +---+
|ES1|-|RB1|-| Area 1 |-|BRB1| |BRB2|-| Area 2 |-|RB2|-|ES2|
+---+ +---+ | | +----+ +----+ | | +---+ +---+
| | | | | |
+--------+ +-----------+ +--------+
|<----TRILL ------>|<IP tunnel>|<-----TRILL ----->|
Figure 1: TRILL interconnection
In Data Center interconnection scenario illustrated in figure 1, a
single SDN Controller or network management system (NMS) can be used
for end-to-end network management. End-to-end topology visibility on
the SDN controller or NMS is very useful for whole network
automation and troubleshooting. BGP LS can be used by the external
SDN controller to collect multiple TRILL domain's link-state.
If ESADI (End Station Address Distribution Information) protocol
[RFC7357] is used for control plane MAC learning in each data center,
BGP LS also can be used for MAC address reachability information
synchronization across multiple TRILL domains. End-to-end unicast
forwarding paths can be calculated based on the synchronized
information.
This document describes the detailed BGP LS extension mechanisms for
TRILL link state and MAC address reachability information
distribution.
2. Conventions used in this document
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].
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BGP - Border Gateway Protocol
BGP-LS - BGP Link-State
Data label - VLAN or FGL (Fine Grained Label [RFC7172])
IS - Intermediate System (for this document, all relevant
intermediate systems are RBridges)
NLRI - Network Layer Reachability Information
SDN - Software Defined Networking
RBridge - A device implementing the TRILL protocol
TRILL - Transparent Interconnection of Lots of Links
3. Carrying TRILL Link-State Information in BGP
In [I-D.ietf-idr-ls-distribution], four NLRI types are defined as
follows: Node NLRI, Link NLRI, IPv4 Topology Prefix NLRI and IPv6
Topology Prefix NLRI. For TRILL link-state distribution, the Node
NLRI and Link NLRI are extended to carry layer 3 gateway role and
link MTU information. TRILL specific attributes are carried using
opaque Node Attribute TLVs, such as nickname, distribution tree
number and identifiers, interested VLANs/Fine Grained Label, and
multicast group address, and etc.
To differentiate TRILL protocol from layer 3 IGP protocol, a new
TRILL Protocol-ID is defined.
+-------------+----------------------------------+
| Protocol-ID | NLRI information source protocol |
+-------------+----------------------------------+
| 1 | IS-IS Level 1 |
| 2 | IS-IS Level 2 |
| 3 | OSPFv2 |
| 4 | Direct |
| 5 | Static configuration |
| 6 | OSPFv3 |
| TBD | TRILL |
+-------------+----------------------------------+
Table 1: Protocol Identifiers
ESADI (End Station Address Distribution Information) protocol
[RFC7357] is a per data label control plane MAC learning solution.
MAC address reachability information is carried in ESADI packets.
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Compared with data plane MAC learning solution, ESADI protocol has
security and fast update advantage that are pointed out in [RFC7357].
For an RBridge that is announcing participation in ESADI, the
RBridge can distribute MAC address reachability information to
external components using BGP. A new NLRI type of ''MAC Reachability
NLRI'' is requested for the MAC address reachability distribution.
+------+---------------------------+
| Type | NLRI Type |
+------+---------------------------+
| 1 | Node NLRI |
| 2 | Link NLRI |
| 3 | IPv4 Topology Prefix NLRI |
| 4 | IPv6 Topology Prefix NLRI |
| TBD | MAC Reachability NLRI |
+------+---------------------------+
Table 2: NLRI Types
The MAC Reachability NLRI uses the format as shown in the following
figure.
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
+-+-+-+-+-+-+-+-+
| Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier |
| (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptor (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// MAC Address Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: The MAC Reachability NLRI format
3.1. Node Descriptors
The Node Descriptor Sub-TLV types include Autonomous System and BGP-
LS Identifier, iS-IS Area-ID and IGP Router-ID. TRILL uses a fixed
zero Area Address as specified in [RFC6325], Section 4.2.3. This is
encoded in a 4-byte Area Address TLV (TLV #1) as follows:
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x01, Area Address Type | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x02, Length of Value | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x01, Length of Address | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00, zero Area Address | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Area Address TLV
3.1.1. IGP Router-ID
Similar to layer 3 IS-IS, TRILL protocol uses 7-octet "IS-IS ID" as
the identity of an RBridge or a pseudonode, IGP Router ID sub-TLV in
Node Descriptor TLVs contains the 7-octet "IS-IS ID". In TRILL
network, each RBridge has a unique 48-bit (6-octet) IS-IS System ID.
This ID may be derived from any of the RBridge's unique MAC
addresses or configured. A pseudonode is assigned a 7-octet ID by
the DRB (Designated RBridge) that created it, the DRB is similar to
the "Designated Intermediate System" (DIS) corresponding to a LAN.
3.2. MAC Address Descriptors
The ''MAC Address Descriptor'' field is a set of Type/Length/Value
(TLV) triplets. ''MAC Address Descriptor'' TLVs uniquely identify an
MAC address reachable by a Node. The following attributes TLVs are
defined:
+--------------+-----------------------+----------+-----------------+
| TLV Code | Description | Length | Value defined |
| Point | | | in: |
+--------------+-----------------------+----------+-----------------+
| 1 | MAC-Reachability | variable | section 3.2.1 |
+--------------+-----------------------+----------+-----------------+
Table 3: MAC Address Descriptor TLVs
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3.2.1. MAC-Reachability TLV
+-+-+-+-+-+-+-+-+
| Type= MAC-RI | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+
|V|F| RESV | Data Label | (4 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (1) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (N) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: MAC-Reachability TLV format
Length is 4 plus a multiple of 6.
The bits of 'V' and 'F' are used to identify Data Label type and are
defined as follows:
+----------+-------------------------+
| Bit | Description |
+----------+-------------------------+
| 'V' | VLAN |
| 'F' | Fine Grained Label |
+----------+-------------------------+
Table 4: Data Label Type Bits Definitions
Notes: If BGP LS is used for NVO3 network MAC address distribution
between external SDN Controller and NVE, Data Label can be used to
represent 24 bits VN ID.
3.3. The BGP-LS Attribute
3.3.1. Node Attribute TLVs
3.3.1.1. Node Flag Bits TLV
A new Node Flag bit is added as follows:
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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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|O|T|E|B|G| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Node Flag Bits TLV format
The new bit and remaining reserved bits are defined as follows:
+----------+----------------------------+-----------+
| Bit | Description | Reference |
+----------+----------------------------+-----------+
| 'G' | Layer 3 Gateway Bit | [RFC7176] |
| Reserved | Reserved for future use | |
+----------+----------------------------+-----------+
Table 5: Node Flag Bits Definitions
3.3.1.2. Opaque Node Attribute TLV
The Opaque Node Attribute TLV is used as the envelope to
transparently carry TRILL specific information. In [RFC7176], there
are the following Sub-TLVs in the Router Capability and MT-
Capability TLVs and the Group Address (GADDR) TLV that need to be
carried. Future possible TRILL TLVs/Sub-TLVs extension also can be
carried using the Opaque Node Attribute TLV.
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Descriptions IS-IS TLV/Sub-TLV
------------------------------------
TRILL-VER 22/13
NICKNAME 22/6
TREES 22/7
TREE-RT-IDs 22/8
TREE-USE-IDs 22/9
INT-VLAN 22/10
VLAN-GROUP 22/14
INT-LABEL 22/15
RBCHANNELS 22/16
AFFINITY 22/17
LABEL-GROUP 22/18
GMAC-ADDR 142/1
GIP-ADDR 142/2
GIPV6-ADDR 142/3
GLMAC-ADDR 142/4
GLIP-ADDR 142/5
GLIPV6-ADDR 142/6
Table 6: TRILL TLVs/Sub-TLVs
3.3.2. Link Attribute TLVs
Link attribute TLVs are TLVs that may be encoded in the BGP-LS
attribute with a link NLRI. Besides the TLVs that has been defined
in [I-D.ietf-idr-ls-distribution] section 3.3.2 table 9, the
following 'Link Attribute' TLV is provided for TRILL.
+-----------+----------------+--------------+------------------+
| TLV Code | Description | IS-IS TLV | Defined in: |
| Point | | /Sub-TLV | |
+-----------+----------------+--------------+------------------+
| TBD | Link MTU | 22/28 | [RFC7176]/2.4 |
+-----------+----------------+--------------+------------------+
Table 7: Link Attribute TLVs
4. Operational Considerations
This document does not require any MIB or Yang model to configure
operational parameters.
An implementation of this specification[idr-ls-trill], MUST do the
malformed attribute checks below, and if it detects a malformed
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attribute, it should use the 'Attribute Discard' action per [I-
D.ietf.idr-error-handling] section 2.
An implementation MUST perform the following expanded [BGP-LS]
syntactic check for determining if the message is malformed:
o Does the sum of all TLVs found in the BGP LS attribute
correspond to the BGP LS path attribute length ?
o Does the sum of all TLVs found in the BGP MP_REACH_NLRI
attribute correspond to the BGP MP_REACH_NLRI length ?
o Does the sum of all TLVs found in the BGP MP_UNREACH_NLRI
attribute correspond to the BGP MP_UNREACH_NLRI length ?
o Does the sum of all TLVs found in a Node-, Link, prefix (IPv4
or IPv6) NLRI attribute correspond to the Node-, Link- or Prefix
Descriptors 'Total NLRI Length' field ?
o Does any fixed length TLV correspond to the TLV Length field
in this document ?
o Does the sum of MAC reachability TLVs equal the length of the
field?
In addition, the following checks need to be made for the fields
specific to the BGP LS for TRILL:
o PROTOCOL ID is TRILL
o NLRI types are valid per table 2
o MAC Reachability NLRI has correct format including:
o Identifier (64 bits),
o local node descriptor with AREA address TLV has
the form found in figure 2,
o opaque TLV support the range of ISIS-TLV/SUB-TLV shown in
table 3, and link TLVs support the range in figure 8.
5. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See [RFC6952] for details.
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6. IANA Considerations
For all of the following assignments, [this document] is the
reference.
IANA is requested to assign one Protocol-ID for "TRILL" from the
BGP-LS registry of Protocol-IDs.
IANA is requested to assign one NLRI Type for "MAC Reachability"
from the BGP-LS registry of NLRI Types.
IANA is requested to assign one Node Flag bit for "Layer 3 Gateway"
from the BGP-LS registry of BGP-LS Attribute TLVs.
IANA is requested to assign one new TLV type for "Link MTU" from the
BGP-LS registry of BGP-LS Attribute TLVs.
7. References
7.1. Normative References
[1] [I-D.ietf-idr-ls-distribution] Gredler, H., Medved, J.,
Previdi, S., Farrel, A., and S.Ray, "North-Bound Distribution of
Link-State and TE Information using BGP", draft-ietf-idr-ls-
distribution-10(work in progress), January 2015.
[2] [I-D.ietf.idr-error-handling] Enke, C., John, S., Pradosh, M.,
Keyur,P., "Revised Error Handling for BGP UPDATE Messages",
draft-ietf-idr-error-handling-19(work in progress), April 2015.
[3] [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[4] [RFC6325] Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S.,and
A. Ghanwani, "Routing Bridges (RBridges): Base Protocol
Specification", RFC 6325, July 2011.
[5] [RFC7172] Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman,
R., and D. Dutt, "Transparent Interconnection of Lots of Links
(TRILL): Fine-Grained Labeling", RFC 7172, DOI 10.17487/RFC7172,
May 2014, <http://www.rfc-editor.org/info/rfc7172>.
[6] [RFC7176] Eastlake, D., Senevirathne, T., Ghanwani, A., Dutt,
D., Banerjee, A.," Transparent Interconnection of Lots of Links
(TRILL) Use of IS-IS'', May 2014.
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[7] [RFC7357] - Zhai, H., Hu, F., Perlman, R., Eastlake 3rd, D.,
and O. Stokes, "Transparent Interconnection of Lots of Links
(TRILL): End Station Address Distribution Information (ESADI)
Protocol", RFC 7357, September 2014, <http://www.rfc-
editor.org/info/rfc7357>.
7.2. Informative References
8. Acknowledgments
Authors like to thank Jie Dong, Mingui Zhang, Qin Wu, Shunwan Wang,
Zitao Wang, Lili Wang for their valuable inputs.
Authors' Addresses
Weiguo Hao
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Phone: +86-25-56623144
Email: haoweiguo@huawei.com
Donald E. Eastlake
Huawei Technologies
155 Beaver Street
Milford, MA 01757 USA
Phone: +1-508-333-2270
Email: d3e3e3@gmail.com
Susan K. Hares
Hickory Hill Consulting
7453 Hickory Hill
Saline, MI 48176 USA
Email: shares@ndzh.com
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