| IDR Working Group | W,. Hao |
| Internet-Draft | D. Eastlake |
| Intended status: Standards Track | S. Hares |
| Expires: September 21, 2016 | Huawei Technologies |
| B. Pithawala | |
| IP Infusion | |
| M. Durrani | |
| Cisco Systems | |
| Y. Li | |
| Huawei Technologies | |
| March 20, 2016 |
Distribution of TRILL Link-State using BGP
draft-ietf-idr-ls-trill-01.txt
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.
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). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://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 September 21, 2016.
Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.
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BGP has been extended to distribute IGP link-state and traffic engineering information to some external components [RFC7752] 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 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.
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]
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
In [RFC7752], 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. 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
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:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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
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.
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
+-+-+-+-+-+-+-+-+
| 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.
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
A new Node Flag bit is added as follows:
+----------+----------------------------+-----------+
| Bit | Description | Reference |
+----------+----------------------------+-----------+
| 'G' | Layer 3 Gateway Bit | [RFC7176] |
| Reserved | Reserved for future use | |
+----------+----------------------------+-----------+
Table 5: Node Flag Bits Definitions
The new bit and remaining reserved bits are defined as follows:
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.
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
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 [RFC7752] 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
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 attribute, it should use the 'Attribute Discard' action per [RFC7606] section 2.
An implementation MUST perform the following expanded [BGP-LS] syntactic check for determining if the message is malformed:
In addition, the following checks need to be made for the fields specific to the BGP LS for TRILL:
Procedures and protocol extensions defined in this document do not affect the BGP security model. See [RFC6952] for details.
This section complies with [RFC7153]. For all of the following assignments, [this document] is the reference.
IANA is requested to 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.
Authors like to thank Andrew Qu, Jie Dong, Mingui Zhang, Qin Wu, Shunwan Zhuang, Zitao Wang, Lili Wang for their valuable inputs.