Internet DRAFT - draft-li-spring-bw-guaranteed-sr
draft-li-spring-bw-guaranteed-sr
Network Working Group Z. Li
Internet-Draft N. Wu
Intended status: Standards Track Huawei Technologies
Expires: September 10, 2015 March 9, 2015
Bandwidth-Guaranteed Segment Routing
draft-li-spring-bw-guaranteed-sr-00
Abstract
The document proposes the bandwidth-guaranteed segment for the
segment routing which can be used to provide the bandwidth-guaranteed
segment routing path to satisfy the QoS requirement of the service.
Accordingly the forwarding mechanisms and the procedures of the
control plane are explained for the bandwidth-guaranteed segment.
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].
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 September 10, 2015.
Copyright Notice
Copyright (c) 2015 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
(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Bandwidth-Guaranteed Segment . . . . . . . . . . . . . . . . 3
4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4.1. End-to-End BW-Guaranteed SR-TE Path . . . . . . . . . . . 3
4.2. Bandwidth Guarantee at Network Boundary Node . . . . . . 3
5. Forwarding Mechanisms . . . . . . . . . . . . . . . . . . . . 4
5.1. Forwarding Mechanisms for BW-Guaranteed Adjacency Segment 4
5.2. Forwarding Mechanisms for BW-Guaranteed Node Segment . . 4
6. Procedures of Control Plane . . . . . . . . . . . . . . . . . 5
6.1. Procedures of BW-Guaranteed Adjacency Segment . . . . . . 5
6.2. Procedures of BW-Guaranteed Node Segment . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Segment Routing (SR), introduced by
[I-D.ietf-spring-segment-routing], leverages the source routing
paradigm. A packet can be steered through an ordered list of
instructions, which are also called segments . The node segment,
adjacency segment, etc. have been proposed for different usecases.
The document proposes the bandwidth-guaranteed segment for the
segment routing which can be used to provide the bandwidth-guaranteed
segment routing path to satisfy the QoS requirement of the service.
Accordingly the forwarding mechanisms and the procedures of the
control plane are explained for the bandwidth-guaranteed segment.
2. Terminology
SID: A Segment Identifier
SR: Segment Routing
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SR Path: Segment Routing Path
SR-TE Path: Segment Routing Traffic Engineering Path
3. Bandwidth-Guaranteed Segment
In the Segment Routing, the bandwidth-guaranteed attributes can be
applied for the node segment or the adjacency segment. These
segments can be called as bandwidth-guaranteed node segment and
bandwidth-guaranteed adjacency segment. When calculate the path to
the specific destination with the bandwidth constraints, the BW-
guaranteed node segment and the BW-guaranteed to compose the
bandwidth-guaranteed segment routing path.
4. Use cases
4.1. End-to-End BW-Guaranteed SR-TE Path
[RFC2702] defines the MPLS TE requirement to provide the end-to-end
bandwidth-guaranteed service. With the BW-guaranteed node segment
and adjacency segment, the Segment Routing can also calculate the
end-to-end BW-guaranteed SR-TE path. Thus the bandwidth-guaranteed
requirement could also be applied in the segment routing to satisfy
the QoS requirement of different services.
4.2. Bandwidth Guarantee at Network Boundary Node
When the traffic leaves the network domain, the QoS process can be
applied to guarantee the service traffic to the neighboring node in
the other network domain. The QoS process can be indicated by the
bandwidth segment in the segment routing path. For example, in the
Figure 1, the bandwidth-guaranteed adjacency segment for the link
between PE2 and CE2 or the bandwidth-guaranteed node segment for CE2
is advertised into the network domain, it can be encapsulated to the
packets at the PE1 as the SR path. When the packet arrives at the
PE2, the BW-guaranteed segment is popped to indicate the QoS process
on the outgoing link to CE2.
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+---------------------+
| |
| |
| |
| Network |
CE1----PE1 PE2----CE2
| Domain |
| |
| |
| |
+---------------------+
Figure 1 Network Domain
5. Forwarding Mechanisms
5.1. Forwarding Mechanisms for BW-Guaranteed Adjacency Segment
For the BW-Guaranteed adjacency segment, since the SID only has the
local semantics, it directly indicates the local outgoing interface
and the corresponding BW-guaranteed process.
+--------------+
+--------+ +---------------------+ | QOS Process |
| SID |--->| Link |QID|--->| based on |
+--------+ +---------------------+ | Bandwidth |
+--------------+
SID: Segment ID
QID: QoS Queue ID
Figure 2 Forwarding Mechanisms for BW-Guaranteed Link Segment
5.2. Forwarding Mechanisms for BW-Guaranteed Node Segment
For the BW-Guaranteed adjacency segment, since the SID only has the
global semantics, it will indicate the outgoing interface to the
specific node and the corresponding BW-guaranteed process on the
outgoing interface.
+---------------------+ +--------------+
+--------+ | Outgoing Link | | | QOS Process |
| SID |--->| to |QID|--->| based on |
+--------+ | Specified Node | | | Bandwidth |
+---------------------+ +--------------+
SID: Segment ID
QID: QoS Queue ID
Figure 3 Forwarding Mechanisms for BW-Guaranteed Node Segment
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6. Procedures of Control Plane
6.1. Procedures of BW-Guaranteed Adjacency Segment
IGP extensions or BGP-LS extensions can be introduced to advertised
the BW-Guaranteed adjacency SID binding for the tuple { Adjacency
Identification, Bandwidth Attribute }. For the initiation router
which advertise the BW-Guaranteed SID binding for the adjacency, it
will install the forwarding entry shown in the Figure 2. The
receiving router will keep the information and continue to flood the
binding information.
6.2. Procedures of BW-Guaranteed Node Segment
IGP extensions or BGP-LS extensions can be introduced to advertised
the BW-Guaranteed node SID binding for the tuple { Node
Identification, Bandwidth Attribute }. For the router receives the
BW-Guaranteed node SID binding, it will look up the FIB to get the
outgoing interface to the node specified by the binding information
and install the forwarding entry shown in the Figure 3. Then it will
continue to flood the binding information.
7. IANA Considerations
This document makes no request of IANA.
8. Security Considerations
TBD.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
9.2. Informative References
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J.,
and E. Crabbe, "Segment Routing Architecture", draft-ietf-
spring-segment-routing-01 (work in progress), February
2015.
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[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
McManus, "Requirements for Traffic Engineering Over MPLS",
RFC 2702, September 1999.
Authors' Addresses
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
Nan Wu
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: eric.wu@huawei.com
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