Internet DRAFT - draft-dawra-spring-bgp-sr-service-chaining
draft-dawra-spring-bgp-sr-service-chaining
Inter-Domain Routing
Internet-Draft
Intended status: Standards Track G. Dawra, Ed.
Expires: May 3, 2018 C. Filsfils
Cisco Systems
D. Bernier
Bell Canada
H. Elmalky
Ericsson
X. Xu
Huawei
F. Clad
Cisco Systems
October 30, 2017
BGP Control Plane for Segment Routing based Service Chaining
draft-dawra-spring-bgp-sr-service-chaining-00
Abstract
The BGP Control Plane for the SR service-chaining solution is
consistent with the BGP Control Plane for the topological Segment
Routing Traffic Engineering (SR-TE) solution.
o BGP Link-State(BGP-LS) address-family/sub-address-family[RFC7752]
is used to discover service and topological characteristics from
the network.
o SR-TE policies[I-D.ietf-idr-segment-routing-te-policy] instantiate
source-routed policies that may mix service and topological
segments.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 3, 2018.
Copyright Notice
Copyright (c) 2017 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BGP-LS Extensions for Service Chaining . . . . . . . . . . . 3
3. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
4.1. Service Type Table . . . . . . . . . . . . . . . . . . . 7
4.2. Segment routing function Identifier(SFI) . . . . . . . . 7
5. Manageability Considerations . . . . . . . . . . . . . . . . 8
6. Operational Considerations . . . . . . . . . . . . . . . . . 8
6.1. Operations . . . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
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.clad-spring-segment-routing-service-chaining] document with an
example network and services.
Let's extend the example to add a Segment Routing Controller (SR-C)
to the network, for the purpose of service discovery and SR policy
instantiation.
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Let's 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.
Let's propose an extension to BGP-LS for Service Chaining to
distribute the service information to SR-C. 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).
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)
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[I-D.clad-spring-segment-routing-service-chaining]defines SR-aware
and SR-unaware services. Let's 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 Node SID TLV [I-D.dawra-idr-bgpls-srv6-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:
+---------------------------------------+
| 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:
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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.
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.
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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.
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.
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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".
+--------------+---------------------------+--------------+----------------+
| 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.clad-spring-segment-routing-service-chaining].
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+--------------------------+---------------------------+
| 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
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
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10.1. Normative References
[I-D.clad-spring-segment-routing-service-chaining]
Clad, F., Filsfils, C., Camarillo, P.,
daniel.bernier@bell.ca, d., Decraene, B., Peirens, B.,
Yadlapalli, C., Xu, X., Salsano, S., Abdelsalam, A., and
G. Dawra, "Segment Routing for Service Chaining", draft-
clad-spring-segment-routing-service-chaining-00 (work in
progress), October 2017.
[I-D.dawra-idr-bgpls-srv6-ext]
Dawra, G., Filsfils, C., Talaulikar, K., Sreekantiah, A.,
and L. Ginsberg, "BGP Link State extensions for IPv6
Segment Routing(SRv6)", draft-dawra-idr-bgpls-srv6-ext-00
(work in progress), October 2017.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<https://www.rfc-editor.org/info/rfc4272>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
[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>.
[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
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[I-D.dawra-bgp-srv6-vpn]
(Unknown), (., Dawra, G., Filsfils, C., Dukes, D.,
Brissette, P., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., daniel.bernier@bell.ca, d.,
Steinberg, D., Raszuk, R., Decraene, B., and S.
Matsushima, "BGP Signaling of IPv6-Segment-Routing-based
VPN Networks", draft-dawra-bgp-srv6-vpn-00 (work in
progress), March 2017.
[I-D.filsfils-spring-segment-routing-policy]
Filsfils, C., Sivabalan, S., Raza, K., Liste, J., Clad,
F., Lin, S., bogdanov@google.com, b., Horneffer, M.,
Steinberg, D., Decraene, B., and S. Litkowski, "Segment
Routing Policy for Traffic Engineering", draft-filsfils-
spring-segment-routing-policy-01 (work in progress), July
2017.
[I-D.filsfils-spring-srv6-network-programming]
Filsfils, C., Leddy, J., daniel.voyer@bell.ca, d.,
daniel.bernier@bell.ca, d., Steinberg, D., Raszuk, R.,
Matsushima, S., Lebrun, D., Decraene, B., Peirens, B.,
Salsano, S., Naik, G., Elmalky, H., Jonnalagadda, P.,
Sharif, M., Ayyangar, A., Mynam, S., Henderickx, W.,
Bashandy, A., Raza, K., Dukes, D., Clad, F., and P.
Camarillo, "SRv6 Network Programming", draft-filsfils-
spring-srv6-network-programming-01 (work in progress),
June 2017.
[I-D.ietf-6man-segment-routing-header]
Previdi, S., Filsfils, C., Raza, K., Leddy, J., Field, B.,
daniel.voyer@bell.ca, d., daniel.bernier@bell.ca, d.,
Matsushima, S., Leung, I., Linkova, J., Aries, E., Kosugi,
T., Vyncke, E., Lebrun, D., Steinberg, D., and R. Raszuk,
"IPv6 Segment Routing Header (SRH)", draft-ietf-6man-
segment-routing-header-07 (work in progress), July 2017.
[I-D.ietf-bess-evpn-prefix-advertisement]
Rabadan, J., Henderickx, W., Drake, J., Lin, W., and A.
Sajassi, "IP Prefix Advertisement in EVPN", draft-ietf-
bess-evpn-prefix-advertisement-08 (work in progress),
October 2017.
[I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Psenak, P., Filsfils, C., Gredler, H., and M.
Chen, "BGP Link-State extensions for Segment Routing",
draft-ietf-idr-bgp-ls-segment-routing-ext-03 (work in
progress), July 2017.
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[I-D.ietf-idr-bgp-prefix-sid]
Previdi, S., Filsfils, C., Lindem, A., Sreekantiah, A.,
and H. Gredler, "Segment Routing Prefix SID extensions for
BGP", draft-ietf-idr-bgp-prefix-sid-07 (work in progress),
October 2017.
[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Mattes, P., Rosen, E., and S.
Lin, "Advertising Segment Routing Policies in BGP", draft-
ietf-idr-segment-routing-te-policy-00 (work in progress),
July 2017.
[I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Filsfils, C., Bashandy, A., Gredler, H.,
Litkowski, S., Decraene, B., and j. jefftant@gmail.com,
"IS-IS Extensions for Segment Routing", draft-ietf-isis-
segment-routing-extensions-13 (work in progress), June
2017.
[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-13 (work
in progress), October 2017.
[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>.
[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>.
[RFC4659] De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur,
"BGP-MPLS IP Virtual Private Network (VPN) Extension for
IPv6 VPN", RFC 4659, DOI 10.17487/RFC4659, September 2006,
<https://www.rfc-editor.org/info/rfc4659>.
[RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network
Layer Reachability Information with an IPv6 Next Hop",
RFC 5549, DOI 10.17487/RFC5549, May 2009,
<https://www.rfc-editor.org/info/rfc5549>.
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Authors' Addresses
Gaurav Dawra (editor)
Cisco Systems
USA
Email: gdawra@cisco.com
Clarence Filsfils
Cisco Systems
Belgium
Email: cfilsfil@cisco.com
Daniel Bernier
Bell Canada
Canada
Email: daniel.bernier@bell.ca
Hani Elmalky
Ericsson
USA
Email: hani.elmalky@gmail.com
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
Francois Clad
Cisco Systems
France
Email: fclad@cisco.com
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