IDR Weiguo Hao
Donald Eastlake
Internet Draft Huawei
Intended status: Standard Track May 18, 2015
Expires: November 2015
Distribution of TRILL Link-State using BGP
draft-hao-idr-ls-trill-00.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 leverage the
information for topology visibility, troubleshooting, network
automation, etc.
Status of this Memo
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carefully, as they describe your rights and restrictions with
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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. OSPF Area-ID....................................... 5
3.1.2. IGP Router-ID...................................... 6
3.2. MAC Address Descriptors................................. 6
3.2.1. MAC-Reachability TLV............................... 7
3.3. The BGP-LS Attribute.................................... 8
3.3.1. Node Attribute TLVs................................ 8
3.3.1.1. Node Flag Bits TLV............................ 8
3.3.1.2. Opaque Node Attribute TLV..................... 8
3.3.2. Link Attribute TLVs................................ 9
4. Operational Considerations................................... 9
5. Security Considerations...................................... 9
6. IANA Considerations ........................................ 10
7. References ................................................. 10
7.1. Normative References................................... 10
7.2. Informative References................................. 11
8. Acknowledgments ............................................ 11
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, SDN controller as an external component
normally can be used to provide centralized control and automation
for the data center network. A holistic view of whole network
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topology on 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,
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 for 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 path can be calculated based on the synchronized
information.
This draft will describe the detail BGP LS extension mechanism 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
IS - Intermediate System (for this document, all relevant
intermediate systems are RBridges)
NLRI - Network Layer Reachability Information
SDN - Software Defined Networking
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 of Node NLRI,
Link NLRI, IPv4 Topology Prefix NLRI and IPv6 Topology Prefix NLRI
are defined. For TRILL link-state distribution, it is suggested that
Node NLRI and Link NLRI be extended to carry layer 3 gateway role
and link MTU information. TRILL specific attributes are suggested to
be 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 |
+-------------+----------------------------------+
ESADI (End Station Address Distribution Information) protocol
[RFC7357] is a control plane MAC learning solution for each
specified data label, 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].
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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 |
+------+---------------------------+
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) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1. Node Descriptors
The Node Descriptor Sub-TLV types include Autonomous System, BGP-LS
Identifier, OSPF Area-ID and IGP Router-ID. The values of OSPF Area-
ID and IGP Router-ID for TRILL network are described as follows.
3.1.1. OSPF Area-ID
It is used to identify the 32 Bit area to which the NLRI belongs.
Area Identifier allows the different NLRIs of the same router to be
discriminated. 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)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.2. 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 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 originated by a Node. The following attributes TLVs are
defined:
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+--------------+-----------------------+----------+-----------------+
| TLV Code | Description | Length | Value defined |
| Point | | | in: |
+--------------+-----------------------+----------+-----------------+
| 1 | MAC-Reachability | variable | section 3.2.1 |
+--------------+-----------------------+----------+-----------------+
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) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length is 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 |
+----------+-------------------------+
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.
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3.3. The BGP-LS Attribute
3.3.1. Node Attribute TLVs
3.3.1.1. Node Flag Bits TLV
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 |
+-+-+-+-+-+-+-+-+-+-+-+
The bits are defined as follows:
+----------+----------------------------+-----------+
| Bit | Description | Reference |
+----------+----------------------------+-----------+
| 'G' | Layer 3 Gateway Bit | [RFC7176] |
| Reserved | Reserved for future use | |
+----------+----------------------------+-----------+
3.3.1.2. Opaque Node Attribute TLV
It is suggested to use the Opaque Node Attribute TLV as the envelope
to transparently carry TRILL specific information. In [RFC 7176],
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
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], the following 'Link Attribute'
TLVs are extended for TRILL.
+-----------+----------------+--------------+------------------+
| TLV Code | Description | IS-IS TLV | Defined in: |
| Point | | /Sub-TLV | |
+-----------+----------------+--------------+------------------+
| TBD | Link MTU | 22/28 | [RFC7176]/2.4 |
+-----------+----------------+--------------+------------------+
4. Operational Considerations
The Existing BGP operational procedures apply to this document. No
new operation procedures are defined in this document. The
operational considerations as specified in [I-D.ietf-idr-ls-
distribution] apply to this document.
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 TLV Code Point 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] [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[3] [RFC6325] Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S.,and A.
Ghanwani, "Routing Bridges (RBridges): Base Protocol
Specification", RFC 6325, July 2011.
[4] [RFC7176] Eastlake, D., Senevirathne, T., Ghanwani, A., Dutt, D.,
Banerjee, A.," Transparent Interconnection of Lots of Links
(TRILL) Use of IS-IS'', May 2014.
[5] [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>.
[6] [RFC6165] Banerjee, A., Ward, D., " Extensions to IS-IS for
Layer-2 Systems'', May 2014.
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7.2. Informative References
8. Acknowledgments
Authors like to thank Susan Hares, 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
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