Inter-Domain Routing G. Dawra, Ed.
Internet-Draft LinkedIn
Intended status: Standards Track C. Filsfils
Expires: January 17, 2019 Cisco Systems
D. Bernier
Bell Canada
J. Uttaro
AT&T
B. Decraene
Orange
H. Elmalky
Ericsson
X. Xu
Alibaba
F. Clad
K. Talaulikar
Cisco Systems
July 16, 2018
BGP-LS Advertisement of Segment Routing Service Segments
draft-dawra-idr-bgp-ls-sr-service-segments-00
Abstract
BGP Link-State (BGP-LS) enables distribution of topology information
from the network to a Path Computation Engine (PCE) or any
controller/application in general so it can learn the network
topology. Service functions are deployed as virtualized elements
along with network elements or on servers in data centers. The
advertisement of such attached service capabilities along with the
network nodes that they are attached to or associated with enable
their discovery and for programming of service paths that use these
service functions. Segment Routing (SR) bring in the concept of
segments which can be topological or service instructions. SR
Policies enable setup of paths which are a mix of topological and
service segments.
This document specifies the extensions to BGP-LS for discovery and
advertisement of service segments so as to enable setup of service
programming paths using Segment Routing.
Requirements Language
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 RFC 2119 [RFC2119].
Dawra, et al. Expires January 17, 2019 [Page 1]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
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). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://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 January 17, 2019.
Copyright Notice
Copyright (c) 2018 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
(https://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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. BGP-LS Extensions for Service Chaining . . . . . . . . . . . 4
3. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
4.1. Service Type Table . . . . . . . . . . . . . . . . . . . 7
4.2. Segment routing function Identifier(SFI) . . . . . . . . 8
5. Manageability Considerations . . . . . . . . . . . . . . . . 8
6. Operational Considerations . . . . . . . . . . . . . . . . . 8
6.1. Operations . . . . . . . . . . . . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
Dawra, et al. Expires January 17, 2019 [Page 2]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
10.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Segments are introduced in the SR architecture
[I-D.ietf-spring-segment-routing]. Segment Routing based Service
chaining is well described in Section 6 of
[I-D.xuclad-spring-sr-service-programming] document with an example
network and services.
This document extend the example to add a Segment Routing Controller
(SR-C) to the network, for the purpose of service discovery and SR
policy instantiation.
Consider the network represented in Figure 1 below where:
o A and B are two end hosts using IPv4.
o S1 is an SR-aware firewall Service.
o S2 is an SR-unaware DPI Service.
SR-C --3--
| / \
| / \
A----1----2----4----5----6----B
| |
| |
S1 S2
Figure 1: Network with Services
SR Controller (SR-C) is connected to Node 1, but may be attached to
any node 1-6 in the network.
SR-C is capable of receiving BGP-LS updates to discover topology, and
calculating constrained paths between 1 and 6.
However, if SR-C is configured to computation a constrained path from
1 and 6, including a DPI service (i.e., S2) it is not yet possible
due to the lack of service distribution. SR-C does not know where a
DPI Service is nor the SID for it. It does not know that S2 is a
service it needs.
This document proposes an extension to BGP-LS for Service Chaining to
distribute the service information to SR-C. There may be other
alternate mechanisms to distribute service information to SR-C and
Dawra, et al. Expires January 17, 2019 [Page 3]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
are outside of scope of this document. There are no extensions
required in SR-TE Policy SAFI.
2. BGP-LS Extensions for Service Chaining
For an attached service, following data needs to be shared with SR-C:
o Service SID value (e.g. MPLS label or IPv6 address). Service SID
MAY only be encoded as LOC:FUNCT, where LOC is the L most
significant bits and FUNCT is the 128-L least significant
bits[I-D.filsfils-spring-srv6-network-programming]. ARGs bits, if
any, MAY be set to 0 in the advertised service SID.
o Function Identifier (Static Proxy, Dynamic Proxy, Shared Memory
Proxy, Masquerading Proxy, SR Aware Service etc).
o Service Type (DPI, Firewall, Classifier, LB etc).
o Traffic Type (IPv4 OR IPv6 OR Ethernet)
o Opaque Data (Such as brand and version, other extra information)
[I-D.xuclad-spring-sr-service-programming] defines SR-aware and SR-
unaware services. This document will reuse these definitions. Per
[RFC7752] Node Attributes are ONLY associated with the Node NLRI.
All non-VPN information SHALL be encoded using AFI 16388 / SAFI 71.
VPN information SHALL be encoded using AFI 16388 / SAFI 72 with
associated RTs.
This document extends SRv6 Node SID TLV
[I-D.dawra-idr-bgpls-srv6-ext] and SR-MPLS SID/Label TLV
[I-D.ietf-idr-bgp-ls-segment-routing-ext] to associate the Service
SID Value with Service-related Information using Service Chaining(SC)
Sub-TLV.
Function Sub-TLV [I-D.dawra-idr-bgpls-srv6-ext] of Node SID TLV
encodes Identifier(Function ID) along with associated Function Flags.
A Service Chaining (SC) Sub-TLV in Figure 2 is defined as:
Dawra, et al. Expires January 17, 2019 [Page 4]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
+---------------------------------------+
| Type (2 octet) |
+---------------------------------------+
| Length (2 octet) |
+---------------------------------------+
| Service Type(ST) (2 octet |
+---------------------------------------+
| Flags (1 octet) |
+---------------------------------------+
| Traffic Type(1 octet) |
+---------------------------------------+
| RESERVED (2 octet) |
+---------------------------------------+
Figure 2: Service Chaining(SC) Sub-TLV
Where:
Type: 16 bit field. TBD
Length: 16 bit field. The total length of the value portion of
the TLV.
Service Type(ST): 16bit field. Service Type: categorizes the
Service: (such as "Firewall", "Classifier" etc).
Flags: 8 bit field. Bits SHOULD be 0 on transmission and MUST be
ignored on reception.
Traffic Type: 8 Bit field. A bit to identify if Service is IPv4
OR IPv6 OR L2 Ethernet Capable. Where:
Bit 0(LSB): Set to 1 if Service is IPv4 Capable
Bit 1: Set to 1 if Service is IPv6 Capable
Bit 2: Set to 1 if Service is Ethernet Capable
RESERVED: 16bit field. SHOULD be 0 on transmission and MUST be
ignored on reception.
Service Type(ST) MUST be encoded as part of SC Sub-TLV.
There may be multiple instances of similar Services that needs to be
distinguished. For example, firewalls made by different vendors A
and B may need to be identified differently because, while they have
similar functionality, their behavior is not identical.
Dawra, et al. Expires January 17, 2019 [Page 5]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
In order for SDN Controller to identify the categories of Services
and their associated SIDs, this section defines the BGP-LS extensions
required to encode these characteristics and other relevant
information about these Services.
Another Optional Opaque Metadata(OM) Sub-TLV of Node SID TLV may
encode vendor specific information. Multiple of OM Sub-TLVs may be
encoded.
+---------------------------------------+
| Type (2 octet) |
+---------------------------------------+
| Length (2 octet) |
+---------------------------------------+
| Opaque Type (2 octet) |
+---------------------------------------+
| Flags (1 octet) |
+---------------------------------------+
| Value (variable) |
+---------------------------------------+
Figure 3: Opaque Metadata(OM) Sub-TLV
o Type: 16 bit field. TBD.
o Length: 16 bit field. The total length of the value portion of
the TLV.
o Opaque Type: 8-bit field. Only publishers and consumers of the
opaque data are supposed to understand the data.
o Flags: 8 bit field. Bits SHOULD be 0 on transmission and MUST be
ignored on reception.
o Value: Variable Length. Based on the data being encoded and
length is recorded in length field.
Opaque Metadata(OM) Sub-TLV defined in Figure 3 may encode propriety
or Service Opaque information such as:
o Vendor specific Service Information.
o Traffic Limiting Information to particular Service Type.
o Opaque Information unique to the Service
o Propriety Enterprise Service specific Information.
Dawra, et al. Expires January 17, 2019 [Page 6]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
3. Illustration
In our SRv6 example above Figure 1 , Node 5 is configured with an
SRv6 dynamic proxy segments (End.AD) C5::AD:F2 for S2.
The BGP-LS advertisement MUST contain and Node SID TLV:
o Service SID: C5::AD:F2 SID
o Function ID: END.AD
The BGP-LS advertisement MUST contain a SC Sub-TLV with:
o Service Type: Deep Packet Inspection(DPI)
o Traffic Type: IPv4 Capable.
The BGP-LS advertisement MAY contain a OM Sub-TLV with:
o Opaque Type: Cisco DPI Version
o Value: 3.5
In our example in Figure 1, using BGP SR-TE SAFI Update
[I-D.ietf-idr-segment-routing-te-policy], SR Controller computes the
candidate path and pushes the Policy.
SRv6 encapsulation policy < CF1::, C3::, C5::AD:F2, C6::D4:B > is
signaled to Node 1 which has mix of service and topological segments.
4. IANA Considerations
This document requests assigning code-points from the registry "BGP-
LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
TLVs".
4.1. Service Type Table
IANA is request to create a new top-level registry called "Service
Type Table (STT)". Valid values are in the range 0 to 65535. Values
0 and 65535 are to be marked "Reserved, not to be allocated".
Dawra, et al. Expires January 17, 2019 [Page 7]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
+------------+-----------------------+------------+-------------+
| Service | Service | Reference | Date |
| Value(TBD) | | | |
+------------+-----------------------+------------+-------------+
| 32 | Classifier | ref-to-set | date-to-set |
+------------+-----------------------+------------+-------------+
| 33 | Firewall | ref-to-set | date-to-set |
+------------+-----------------------+------------+-------------+
| 34 | Load Balancer | ref-to-set | date-to-set |
+------------+-----------------------+------------+-------------+
| 35 | DPI | ref-to-set | date-to-set |
+------------+-----------------------+------------+-------------+
Figure 4
4.2. Segment routing function Identifier(SFI)
IANA is request to extend a top-level registry called "Segment
Routing Function Identifier(SFI)" with new code points. This
document extends the SFI values defined in
[I-D.dawra-idr-bgpls-srv6-ext]. Details about the Service functions
are defined in[I-D.xuclad-spring-sr-service-programming].
+--------------------------+---------------------------+
| Function | Function Identifier |
| | |
+--------------------------+---------------------------+
| Static Proxy | 8 |
+--------------------------+---------------------------+
| Dynamic Proxy | 9 |
+--------------------------+---------------------------+
| Shared Memory Proxy | 10 |
+--------------------------+---------------------------+
| Masquerading Proxy | 11 |
+--------------------------+---------------------------+
| SRv6 Aware Service | 12 |
+--------------------------+---------------------------+
5. Manageability Considerations
This section is structured as recommended in[RFC5706]
6. Operational Considerations
Dawra, et al. Expires January 17, 2019 [Page 8]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
6.1. Operations
Existing BGP and BGP-LS operational procedures apply. No additional
operation procedures are defined in this document.
7. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See the 'Security Considerations'
section of [RFC4271] for a discussion of BGP security. Also refer
to[RFC4272] and[RFC6952] for analysis of security issues for BGP.
8. Conclusions
This document proposes extensions to the BGP-LS to allow discovery of
Services using Segment Routing.
9. Acknowledgements
The authors would like to thank Krishnaswamy Ananthamurthy for his
review of this document.
10. References
10.1. Normative References
[I-D.dawra-idr-bgpls-srv6-ext]
Dawra, G., Filsfils, C., Talaulikar, K., Chen, M.,
daniel.bernier@bell.ca, d., Uttaro, J., Decraene, B., and
H. Elmalky, "BGP Link State extensions for IPv6 Segment
Routing(SRv6)", draft-dawra-idr-bgpls-srv6-ext-03 (work in
progress), March 2018.
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-15 (work
in progress), January 2018.
[I-D.xuclad-spring-sr-service-programming]
Clad, F., Xu, X., Filsfils, C., daniel.bernier@bell.ca,
d., Li, C., Decraene, B., Ma, S., Yadlapalli, C.,
Henderickx, W., and S. Salsano, "Service Programming with
Segment Routing", draft-xuclad-spring-sr-service-
programming-00 (work in progress), July 2018.
Dawra, et al. Expires January 17, 2019 [Page 9]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
[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>.
[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>.
10.2. Informative References
[I-D.filsfils-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
Network Programming", draft-filsfils-spring-srv6-network-
programming-05 (work in progress), July 2018.
[I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-08
(work in progress), May 2018.
[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Jain, D., Mattes, P., Rosen,
E., and S. Lin, "Advertising Segment Routing Policies in
BGP", draft-ietf-idr-segment-routing-te-policy-04 (work in
progress), July 2018.
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d.,
bogdanov@google.com, b., and P. Mattes, "Segment Routing
Policy Architecture", draft-ietf-spring-segment-routing-
policy-01 (work in progress), June 2018.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<https://www.rfc-editor.org/info/rfc4272>.
Dawra, et al. Expires January 17, 2019 [Page 10]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
[RFC5706] Harrington, D., "Guidelines for Considering Operations and
Management of New Protocols and Protocol Extensions",
RFC 5706, DOI 10.17487/RFC5706, November 2009,
<https://www.rfc-editor.org/info/rfc5706>.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<https://www.rfc-editor.org/info/rfc6952>.
Authors' Addresses
Gaurav Dawra (editor)
LinkedIn
USA
Email: gdawra.ietf@gmail.com
Clarence Filsfils
Cisco Systems
Belgium
Email: cfilsfil@cisco.com
Daniel Bernier
Bell Canada
Canada
Email: daniel.bernier@bell.ca
Jim Uttaro
AT&T
USA
Email: ju1738@att.com
Bruno Decraene
Orange
France
Email: bruno.decraene@orange.com
Dawra, et al. Expires January 17, 2019 [Page 11]
Internet-Draft BGP-LS Extensions for SR Service Segments July 2018
Hani Elmalky
Ericsson
USA
Email: hani.elmalky@gmail.com
Xiaohu Xu
Alibaba
Email: xiaohu.xxh@alibaba-inc.com
Francois Clad
Cisco Systems
France
Email: fclad@cisco.com
Ketan Talaulikar
Cisco Systems
India
Email: ketant@cisco.com
Dawra, et al. Expires January 17, 2019 [Page 12]