BGP-LS Extensions for Transport Slice
draft-chen-idr-bgp-ls-transport-slice-00
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| Author | Ran Chen | ||
| Last updated | 2020-01-21 | ||
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draft-chen-idr-bgp-ls-transport-slice-00
IDR R. Chen
Internet-Draft Sh. Peng
Intended status: Standards Track ZTE Corporation
Expires: July 25, 2020 January 22, 2020
BGP-LS Extensions for Transport Slice
draft-chen-idr-bgp-ls-transport-slice-00
Abstract
[I-D.peng-teas-network-slicing]defines a unified TN-slice identifier,
AII(administrative instance identifier), to indicate the topology,
computing, storage resources of the dedicated virtual network for
both intra-domain and inter-domain network slicing scenarios. This
draft defines extensions to BGP-LS protocol in order to advertise the
information of the transport slice.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 25, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
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include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. BGP-LS Extensions for transport slice . . . . . . . . . . . . 3
3.1. Node Attributes TLV . . . . . . . . . . . . . . . . . . . 3
3.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . . . 4
3.2.1. TN-slice Identifier list sub-TLV . . . . . . . . . . 4
3.2.2. L2 Bundle Member TN-Slice Identifier TLV . . . . . . 5
3.2.3. Adjacency-SID for TN-slice Identifier TLV . . . . . . 5
3.2.4. LAN-Adj-SID for TN-slice Identifier TLV . . . . . . . 6
3.3. Prefix Attribute TLVs . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
6. Normative References . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
For a packet network, network slicing requires the underlying network
to support partitioning of the network resources to provide the
client with dedicated (private) networking, computing, and storage
resources drawn from a shared pool.
[I-D.peng-teas-network-slicing]defines a unified TN-slice identifier,
AII(administrative instance identifier), to indicate the topology,
computing, storage resources of the dedicated virtual network for
both intra-domain and inter-domain network slicing scenarios, and how
to compute SR-BE or SR-TE path according to TN-slice Identifier
combined with other criteria.
[I-D.zch-lsr-isis-network-slicing]defines the IS-IS extensions
required to distribute TN-slice Identifier(that is AII) information
in an AS.
In order to satisfy the need for applications that require
topological visibility across one area or Autonomous System (AS).
This document specifies extensions to the BGP Link-state address-
family in order to advertise TN-slice specific. An external
component (e.g., a controller) then can collect TN-slice information
in the "northbound" direction.
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2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"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.
3. BGP-LS Extensions for transport slice
The following transport slice information TLV is defined: BGP-
LS[[RFC7752]]defines the link-state NLRI that can be a Node NLRI, a
Link NLRI or a Prefix NLRI. BGP-LS[[RFC7752]]defines the TLVs that
map link-state information to BGP link-state NLRI within the BGP-LS
Attribute. This document adds additional BGP-LS Attribute TLVs in
order to encode TN-slice information. It does not introduce any
changes to the encoding of the BGP-LS NLRIs.
3.1. Node Attributes TLV
The TN-slice identifier Participation TLV is used in order to
advertise which TN-slice a router wants to take part in. The TN-
slice identifier Participation sub-TLV is a new TLV of the optional
BGP-LS Attribute that is associated with the node NLRI. This
information is derived from TN-slice identifier Participation sub-TLV
of IS-IS (section 3 of [I-D.zch-lsr-isis-network-slicing].
The TN-slice identifier Participation TLV 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=TBD1 | Length | Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII for virtual networks 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII for virtual networks N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: TN-slice identifier Participation TLV
where:
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Type: TBD1 (Suggested value to be assigned by IANA)
Length: variable.
Number:Number of virtual networks.
AII for VN: allocate different TN-slice identifier (AII) for
different virtual networks. AII is used to distinguish different
virtual network resources.
3.2. Link Attribute TLVs
The following Link Attribute TLVs are are defined:
+-------+---------------------------------------------+
| Type | Description |
+-------+---------------------------------------------+
| TBD2 | The TN-slice Identifier list TLV |
| TBD3 | L2 Bundle Member TN-Slice Identifier TLV |
| TBD4 | Adjacency-SID for TN-slice Identifier TLV |
| TBD5 | LAN-Adj-SID for TN-slice Identifier TLV |
+-------+---------------------------------------------+
Table 1:The new Link Attribute TLVs
These TLVs should only be added to the BGP-LS Attribute associated
with the Link NLRI.
3.2.1. TN-slice Identifier list sub-TLV
TN-slice Identifier can be used to color links to partition underlay
resource. This section is derived from TN-slice Identifier list sub-
TLV of IS-IS (section 4 of [I-D.zch-lsr-isis-network-slicing].)
The TN-slice Identifier list TLV has the following format:
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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=TBD2 | Length | Reserved | Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII for virtual networks 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII for virtual networks N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
Type: TBD2 (Suggested value to be assigned by IANA)
Length: variable.
Number:Number of virtual networks.
AII for VN: allocate different TN-slice identifier (AII) for
different virtual networks. AII is used to distinguish different
virtual network resources.
3.2.2. L2 Bundle Member TN-Slice Identifier TLV
This TLV is used to advertise TN-slice Identifier for L2 Bundle
Member associated with a parent L3 adjacency which is Point-to-Point.
This information is derived from TN-slice Identifier for L2 Bundle
Member sub-TLV of IS-IS (section 5 of
[I-D.zch-lsr-isis-network-slicing].).The following format is defined
for this sub-TLV:
Type: TBD3.
Length: variable
L2 Bundle Member TN-slice Identifier.There MUST be one TN-slice
Identifier(AII) for each of the L2 Bundle Members advertised under
the preceding L2 Bundle Member Attribute Descriptor.
3.2.3. Adjacency-SID for TN-slice Identifier TLV
This TLV is used to distinguish forwarding behavior of different
virtual networks, Adjacency-SID need to be allocated per TN-slice
Identifier. This information is derived from TN-slice Identifier for
Adjacency-SID for TN-slice Identifier sub-TLV of IS-IS (section 7 of
[I-D.zch-lsr-isis-network-slicing] ).
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The following format is defined for this sub-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=TBD4 | Length | Flag | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label(Variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3
where:
Type:TBD4(Suggested value to be assigned by IANA)
Length: Variable. Depending on the size of the SID.
The "Flags" and "SID/Index/Label" fields are the same as the
Adjacency-SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].
AII: Identifies the TN-slice (AII) information corresponding to the
Adjacency-SID.
3.2.4. LAN-Adj-SID for TN-slice Identifier TLV
In LAN subnetworks,[
[I-D.ietf-isis-segment-routing-extensions]]defines the LAN-Adj-SID
sub-TLV for a router to advertise the Adj-SID of each of its
neighbors.
LAN-Adj-SID for TN-slice Identifier TLV is used to distinguish
forwarding behavior of different virtual networks, Adjacency-SID need
to be allocated per TN-slice Identifier. This information is derived
from the LAN-Adj-SID for TN-slice Identifier sub-TLV of IS-IS
(section 8 of I-D. [I-D.zch-lsr-isis-network-slicing] ).
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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=TBD5 | Length | Flags | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor System-ID (ID length octets) |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Label/Index (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4
where:
Type:TBD5 (Suggested value to be assigned by IANA)
Length: Variable. Depending on the size of the SID.
The "Flags" and "SID/Index/Label" fields are the same as the
Adjacency-SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].
AII: Identifies the TN-slice (AII) information corresponding to the
Adjacency-SID.
3.3. Prefix Attribute TLVs
Prefix-SID for TN-slice Identifier TLV should only be added to the
BGP-LS Attribute associated with the Prefix NLRI describing the
prefix of the IGP node. This TLV is used to distinguish forwarding
behavior of different virtual networks.This information is derived
from TN-slice identifier Participation sub-TLV of IS-IS (section 6 of
[I-D.zch-lsr-isis-network-slicing]).
The Prefix-SID for TN-slice Identifier TLV has the following format:
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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=TBD6 | Length | Flag | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label(Variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5
where:
Type:TBD6 (Suggested value to be assigned by IANA)
Length: Variable. Depending on the size of the SID.
The "Flags" and "SID/Index/Label" fields are the same as the Prefix-
SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].
Algorithm: Accoridng to section "3.2. SR-Algorithm Sub-TLV" of
>[I-D.ietf-isis-segment-routing-extensions], two values can be set in
this field.
o 0: Shortest Path First (SPF) algorithm based on link metric.
o 1: Strict Shortest Path First (SPF) algorithm based on link
metric.
Note that[I-D.ietf-lsr-flex-algo]also allows user to define other
algorithm values, i.e., FA-id within [128, 255], for the purpose of
constraint based path computation.However, an FA-id algorithm value
MUST not be set in this field, the reason is that FA-id has not
semantic local within AII.
AII: Identifies the TN-slice (AII) information corresponding to the
Prefix-SID.
4. IANA Considerations
This document does not define any new protocol or any extension to an
existing protocol.
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5. Acknowledgements
TBD
6. Normative References
[I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Gredler, H., and B. Decraene, "IS-IS Extensions for
Segment Routing", draft-ietf-isis-segment-routing-
extensions-25 (work in progress), May 2019.
[I-D.ietf-lsr-flex-algo]
Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex-
algo-05 (work in progress), November 2019.
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Sivabalan, S., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", draft-
ietf-spring-segment-routing-policy-06 (work in progress),
December 2019.
[I-D.peng-teas-network-slicing]
Peng, S., Chen, R., Mirsky, G., and F. Qin, "Packet
Network Slicing using Segment Routing", draft-peng-teas-
network-slicing-02 (work in progress), December 2019.
[I-D.zch-lsr-isis-network-slicing]
Zhu, Y., Chen, R., Peng, S., and F. Qin, "IS-IS Extensions
to Support Packet Network Slicing using Segment Routing",
draft-zch-lsr-isis-network-slicing-03 (work in progress),
December 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, DOI 10.17487/RFC4915, June 2007,
<https://www.rfc-editor.org/info/rfc4915>.
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[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
Authors' Addresses
Ran Chen
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: chen.ran@zte.com.cn
Shaofu
ZTE Corporation
No.68 Zijinghua Road, Yuhuatai District
Nanjing
China
Email: peng.shaofu@zte.com.cn
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