< draft-wu-idr-te-pm-bgp-02.txt   draft-wu-idr-te-pm-bgp-03.txt >
IDR Working Group Q. Wu IDR Working Group Q. Wu
Internet-Draft D. Wang Internet-Draft D. Wang
Intended status: Standards Track Huawei Intended status: Standards Track Huawei
Expires: April 13, 2014 S. Previdi Expires: April 24, 2014 S. Previdi
Cisco Cisco
H. Gredler H. Gredler
Juniper Juniper
S. Ray S. Ray
Cisco Cisco
October 10, 2013 October 21, 2013
BGP attribute for North-Bound Distribution of Traffic Engineering (TE) BGP attribute for North-Bound Distribution of Traffic Engineering (TE)
performance Metrics performance Metrics
draft-wu-idr-te-pm-bgp-02 draft-wu-idr-te-pm-bgp-03
Abstract Abstract
In order to populate network performance information like link In order to populate network performance information like link
latency, latency variation, packet loss and bandwidth into Traffic latency, latency variation, packet loss and bandwidth into Traffic
Engineering Database(TED) and ALTO server, this document describes Engineering Database(TED) and ALTO server, this document describes
extensions to BGP protocol, that can be used to distribute network extensions to BGP protocol, that can be used to distribute network
performance information (such as link delay, delay variation, packet performance information (such as link delay, delay variation, packet
loss, residual bandwidth, and available bandwidth). loss, residual bandwidth, available bandwidth and utilized bandwidth
).
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 13, 2014. This Internet-Draft will expire on April 24, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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3.1. MPLS-TE with PCE . . . . . . . . . . . . . . . . . . . . . 5 3.1. MPLS-TE with PCE . . . . . . . . . . . . . . . . . . . . . 5
3.2. ALTO Server Network API . . . . . . . . . . . . . . . . . 5 3.2. ALTO Server Network API . . . . . . . . . . . . . . . . . 5
4. Carrying TE Performance information in BGP . . . . . . . . . . 7 4. Carrying TE Performance information in BGP . . . . . . . . . . 7
5. Attribute TLV Details . . . . . . . . . . . . . . . . . . . . 9 5. Attribute TLV Details . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . . 12 8.1. Normative References . . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . . 12 8.2. Informative References . . . . . . . . . . . . . . . . . . 12
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 13 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 13
A.1. draft-wu-idr-te-pm-bgp-02 . . . . . . . . . . . . . . . . 13 A.1. draft-wu-idr-te-pm-bgp-03 . . . . . . . . . . . . . . . . 13
A.2. draft-wu-idr-te-pm-bgp-02 . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
As specified in [RFC4655],a Path Computation Element (PCE) is an As specified in [RFC4655],a Path Computation Element (PCE) is an
entity that is capable of computing a network path or route based on entity that is capable of computing a network path or route based on
a network graph, and of applying computational constraints during the a network graph, and of applying computational constraints during the
computation. In order to compute an end to end path, the PCE needs computation. In order to compute an end to end path, the PCE needs
to have a unified view of the overall topology[I-D.ietf-pce-pcep- to have a unified view of the overall topology[I-D.ietf-pce-pcep-
service-aware]. [I.D-ietf-idr-ls-distribution] describes a mechanism service-aware]. [I.D-ietf-idr-ls-distribution] describes a mechanism
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BGP routing protocol. This mechanism can be used by both PCE and BGP routing protocol. This mechanism can be used by both PCE and
ALTO server to gather information about the topologies and ALTO server to gather information about the topologies and
capabilities of the network. capabilities of the network.
With the growth of network virtualization technology, the needs for With the growth of network virtualization technology, the needs for
inter-connection between various overlay technologies (e.g. inter-connection between various overlay technologies (e.g.
Enterprise BGP/MPLS IP VPNs) in the Wide Area Network (WAN) become Enterprise BGP/MPLS IP VPNs) in the Wide Area Network (WAN) become
important. The Network performance or QoS requirements such as important. The Network performance or QoS requirements such as
latency, limited bandwidth, packet loss, and jitter, are all critical latency, limited bandwidth, packet loss, and jitter, are all critical
factors that must be taken into account in the end to end path factors that must be taken into account in the end to end path
computation ([I-D.ietf-pce-pcep-service-aware])and selection which computation ([I-D.ietf-pce-pcep-service-aware]) and selection which
enable establishing segment overlay tunnel between overlay nodes and enable establishing segment overlay tunnel between overlay nodes and
stitching them together to compute end to end path. stitching them together to compute end to end path.
In order to populate network performance information like link In order to populate network performance information like link
latency, latency variation, packet loss and bandwidth into TED and latency, latency variation, packet loss and bandwidth into TED and
ALTO server, this document describes extensions to BGP protocol, that ALTO server, this document describes extensions to BGP protocol, that
can be used to distribute network performance information (such as can be used to distribute network performance information (such as
link delay, delay variation, packet loss, residual bandwidth, and link delay, delay variation, packet loss, residual bandwidth,
available bandwidth). available bandwidth, and utilized bandwidth).
2. Conventions used in this document 2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [RFC2119]. document are to be interpreted as described in RFC2119 [RFC2119].
3. Use Cases 3. Use Cases
3.1. MPLS-TE with PCE 3.1. MPLS-TE with PCE
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4. Carrying TE Performance information in BGP 4. Carrying TE Performance information in BGP
This document proposes new BGP TE performance TLVs that can be This document proposes new BGP TE performance TLVs that can be
announced as attribute in the BGP-LS attribute (defined in [I.D-ietf- announced as attribute in the BGP-LS attribute (defined in [I.D-ietf-
idr- ls-distribution]) to distribute network performance information. idr- ls-distribution]) to distribute network performance information.
The extensions in this document build on the ones provided in BGP-LS The extensions in this document build on the ones provided in BGP-LS
[I.D -ietf-idr-ls-distribution] and BGP-4 [RFC4271]. [I.D -ietf-idr-ls-distribution] and BGP-4 [RFC4271].
BGP-LS attribute defined in [I.D-ietf-idr-ls-distribution] has nested BGP-LS attribute defined in [I.D-ietf-idr-ls-distribution] has nested
TLVs which allow the BGP-LS attribute to be readily extended. This TLVs which allow the BGP-LS attribute to be readily extended. This
document proposes six additional TLVs as its attributes: document proposes seven additional TLVs as its attributes:
Type Value Type Value
TBD1 Unidirectional Link Delay TBD1 Unidirectional Link Delay
TBD2 Min/Max Unidirectional Link Delay TBD2 Min/Max Unidirectional Link Delay
TBD3 Unidirectional Delay Variation TBD3 Unidirectional Delay Variation
TBD4 Unidirectional Packet Loss TBD4 Unidirectional Packet Loss
TBD5 Unidirectional Residual Bandwidth TBD5 Unidirectional Residual Bandwidth
TBD6 Unidirectional Available Bandwidth TBD6 Unidirectional Available Bandwidth
[ Editor Note: When this draft(v-01) was presented in the IDR WG TBD7 Unidirectional Utilized Bandwidth
session of Berlin meeting,John Scudder suggested to define new
attributes(i.e.,link utilization attribute, channel throughput
attribute) added in the previous version of this draft in the
draft-ietf-isis-te-metric-extensions. After Berlin meeting, Hannes
Gredler help initiate discussion with authors of IGP drafts(i.e.,
draft-ietf-isis-te-metric-extensions and
draft-ietf-ospf-te-metric-extensions) on why two additional
attributes should be added into IGP draft. After a few offline
discussion with authors of IGP drafts, specially with John Drake,
David Ward, Alia Atlas,Stefano Previdi,it was roughly agreed that
o drop channel throughput attribute since it is node attribute
rather than link attribute.
o and add link utilization attribute into IGP drafts.
However the open issue is whether defining total Link Utilization as
Currently Utilized Bandwidth or as Currently Utilized Bandwidth /
Maximum Bandwidth. Until this open issue is resolved, the link
utilization attribute will the added into the update of this draft as
seventh additional TLV. ]
As can be seen in the list above, the TLVs described in this document As can be seen in the list above, the TLVs described in this document
carry different types of network performance information. These TLVs carry different types of network performance information. These TLVs
include a bit called the Anomalous (or "A") bit at the left-most bit include a bit called the Anomalous (or "A") bit at the left-most bit
after length field of each TLV. The other bits in the first octets after length field of each TLV. The other bits in the first octets
after length field of each TLV is reserved for future use. When the after length field of each TLV is reserved for future use. When the
A bit is clear (or when the TLV does not include an A bit), the TLV A bit is clear (or when the TLV does not include an A bit), the TLV
describes steady state link performance. This information could describes steady state link performance. This information could
conceivably be used to construct a steady state performance topology conceivably be used to construct a steady state performance topology
for initial tunnel path computation, or to verify alternative for initial tunnel path computation, or to verify alternative
failover paths. failover paths.
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new path. If link performance improves later and falls below a new path. If link performance improves later and falls below a
configurable value, that TLV can be re- advertised with the Anomalous configurable value, that TLV can be re- advertised with the Anomalous
bit cleared. In this case, a receiving BGP peer can conceivably do bit cleared. In this case, a receiving BGP peer can conceivably do
whatever re-optimization (or failback) it wishes to do (including whatever re-optimization (or failback) it wishes to do (including
nothing). nothing).
Note that when a TLV does not include the A bit, that TLV cannot be Note that when a TLV does not include the A bit, that TLV cannot be
used for failover purposes. The A bit was intentionally omitted from used for failover purposes. The A bit was intentionally omitted from
some TLVs to help mitigate oscillations. some TLVs to help mitigate oscillations.
Consistent with existing ISIS TE specifications [ISIS-TE- METRIC], Consistent with existing ISIS TE specifications [ISIS-TE-METRIC], the
the bandwidth advertisements,the delay and delay variation bandwidth advertisements,the delay and delay variation
advertisements, packetloss defined in this document MUST be encoded advertisements, packetloss defined in this document MUST be encoded
in the same unit as one defined in IS-IS Extended IS Reachability in the same unit as one defined in IS-IS Extended IS Reachability
sub-TLVs [ISIS-TE- METRIC]. All values (except residual bandwidth) sub-TLVs [ISIS-TE-METRIC]. All values (except residual bandwidth)
MUST be calculated as rolling averages where the averaging period MUST be calculated as rolling averages where the averaging period
MUST be a configurable period of time. MUST be a configurable period of time.
5. Attribute TLV Details 5. Attribute TLV Details
Link attribute TLVs defined in section 3.2.2 of [I-D.ietf-idr-ls- Link attribute TLVs defined in section 3.2.2 of [I-D.ietf-idr-ls-
distribution]are TLVs that may be encoded in the BGP-LS attribute distribution]are TLVs that may be encoded in the BGP-LS attribute
with a link NLRI. Each 'Link Attribute' is a Type/Length/ Value with a link NLRI. Each 'Link Attribute' is a Type/Length/ Value
(TLV) triplet formatted as defined in Section 3.1 of [I-D.ietf-idr- (TLV) triplet formatted as defined in Section 3.1 of [I-D.ietf-id r-
ls-distribution]. The format and semantics of the 'value' fields in ls-distribution]. The format and semantics of the 'value' fields in
some 'Link Attribute' TLVs correspond to the format and semantics of some 'Link Attribute' TLVs correspond to the format and semantics of
value fields in IS-IS Extended IS Reachability sub-TLVs, defined in value fields in IS-IS Extended IS Reachability sub-TLVs, defined in
[RFC5305]. Although the encodings for 'Link Attribute' TLVs were [RFC5305]. Although the encodings for 'Link Attribute' TLVs were
originally defined for IS-IS, the TLVs can carry data sourced either originally defined for IS-IS, the TLVs can carry data sourced either
by IS-IS or OSPF. by IS-IS or OSPF.
The following 'Link Attribute' TLVs are valid in the LINK_STATE The following 'Link Attribute' TLVs are valid in the LINK_STATE
attribute: attribute:
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| | | | | | | | | |
| xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.4 | | xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.4 |
| | Link Loss | | | | | Link Loss | | |
| | | | | | | | | |
| xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.5 | | xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.5 |
| |Residual Bandwidth | | | | |Residual Bandwidth | | |
| | | | | | | | | |
| xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.6 | | xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.6 |
| |Available Bandwidth | | | | |Available Bandwidth | | |
| | | | | | | | | |
| xxxx | Unidirectional | 22/xx | [ISIS-TE]/4.7 |
| |Utilized Bandwidth | | |
+------------+---------------------+--------------+-----------------+ +------------+---------------------+--------------+-----------------+
Table 1: Link Attribute TLVs Table 1: Link Attribute TLVs
[ Editor Note: The open issue is whether defining total Link
Utilization as Currently Utilized Bandwidth or as Currently Utilized
Bandwidth / Maximum Bandwidth? We will add link utilization
attribute as seventh additional attribute(e.g.,Currently Utilized
Bandwidth) when the open issue is resolved. ]
6. Security Considerations 6. Security Considerations
This document does not introduce security issues beyond those This document does not introduce security issues beyond those
discussed in [I.D-ietf-idr-ls-distribution] and [RFC4271]. discussed in [I.D-ietf-idr-ls-distribution] and [RFC4271].
7. IANA Considerations 7. IANA Considerations
IANA maintains the registry for the TLVs. BGP TE Performance TLV IANA maintains the registry for the TLVs. BGP TE Performance TLV
will require one new type code per TLV defined in this document. will require one new type code per TLV defined in this document.
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May 2013. May 2013.
[RFC4655] Farrel, A., "A Path Computation Element (PCE)-Based [RFC4655] Farrel, A., "A Path Computation Element (PCE)-Based
Architecture", RFC 4655, August 2006. Architecture", RFC 4655, August 2006.
Appendix A. Change Log Appendix A. Change Log
Note to the RFC-Editor: please remove this section prior to Note to the RFC-Editor: please remove this section prior to
publication as an RFC. publication as an RFC.
A.1. draft-wu-idr-te-pm-bgp-02 A.1. draft-wu-idr-te-pm-bgp-03
The following are the major changes compared to previous version 02:
o Add unidirectional utilized bandwidth metric as the seventh metric
Carried in a new BGP attribute.
A.2. draft-wu-idr-te-pm-bgp-02
The following are the major changes compared to previous version 01: The following are the major changes compared to previous version 01:
o Taking out link utilization metric and channel throughput metric o Taking out link utilization metric and channel throughput metric
from this version and will add link utilization metric back to the from this version and will add link utilization metric back to the
update when there was agreement on what measurement unit is used update when there was agreement on what measurement unit is used
for link utilization. for link utilization.
o Some additional texts in BGP extension section 4 to explain how to o Some additional texts in BGP extension section 4 to explain how to
position 'A' bit in the BGP TE performance TLV. position 'A' bit in the BGP TE performance TLV.
 End of changes. 17 change blocks. 
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