Internet DRAFT - draft-chen-teas-rsvp-tts
draft-chen-teas-rsvp-tts
Internet Engineering Task Force H. Chen
Internet-Draft Huawei Technologies
Intended status: Standards Track M. Toy
Expires: January 21, 2018 Verizon
V. Liu
China Mobile
L. Liu
Fijitsu
July 20, 2017
Extensions to MPLS for Temporal LSP
draft-chen-teas-rsvp-tts-02.txt
Abstract
This document specifies extensions to RSVP-TE for creating and
maintaining a Traffic Engineering (TE) Label Switched Path (LSP) in a
time interval or a sequence of time intervals.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Conventions Used in This Document . . . . . . . . . . . . . . 3
4. Temporal LSP Overview . . . . . . . . . . . . . . . . . . . . 4
4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 4
4.2. Operations Overview . . . . . . . . . . . . . . . . . . . 4
5. TIME INTERVAL Object . . . . . . . . . . . . . . . . . . . . . 5
5.1. Absolute TIME INTERVAL Object . . . . . . . . . . . . . . 5
5.2. Relative TIME INTERVAL Object . . . . . . . . . . . . . . 6
5.3. Recurrent Absolute TIME INTERVAL Object . . . . . . . . . 7
5.4. Recurrent Relative TIME INTERVAL Object . . . . . . . . . 8
6. Path Message . . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Behaviors for Temporal LSP . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 10
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
11.1. Normative References . . . . . . . . . . . . . . . . . . . 10
11.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
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1. Introduction
Once an existing multiprotocol label switching (MPLS) traffic
engineering (TE) label switched path (LSP) is set up, it is assumed
to carry traffic forever until it is down. When an MPLS TE LSP
tunnel is up, it is assumed that the LSP consumes its reserved
network resources forever even though the LSP may only use network
resources during some period of time. As a result, the network
resources are not used efficiently. Moreover, a tunnel service can
not be reserved or booked in advance in a period of time.
This document specifies extensions to RSVP-TE for creating and
maintaining an MPLS TE LSP in a period of time called a time interval
or a sequence of time intervals. It is assumed that the LSP carries
traffic during this time interval or each of these time intervals.
Thus the network resources are efficiently used. More importantly,
some new services can be provided. For example, a consumer can book
a tunnel service in advance for a given time interval. Tunnel
services may be scheduled as requested.
2. Terminology
A Time Interval: a time period from time Ta to time Tb.
LSP: Label Switched Path. An LSP is a P2P (point-to-point) LSP or a
P2MP (point-to-multipoiint) LSP.
LSP in a time interval: LSP that carries traffic in the time
interval.
LSP in a sequence of time intervals: LSP that carries traffic in each
of the time intervals.
Temporal LSP: LSP in a time interval or LSP in a sequence of time
intervals.
TEDB: Traffic Engineering Database.
This document uses terminologies defined in RFC3209 and RFC4875.
3. Conventions Used in This Document
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 RFC2119.
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4. Temporal LSP Overview
This section briefs the architecture for supporting temporal LSPs and
some operations on temporal LSPs.
4.1. Architecture Overview
Based on the existing architecture for supporting TE LSPs, we can
extend a few of components to support temporal LSPs. These
components include OSPF, CSPF and RSVP-TE.
OSPF is extended to distribute and maintain TE inforamtion for a link
in a sequence of time intervals. CSPF is extended to compute a path
for a temporal LSP based on the TEDB containing TE information for
every link in a sequence of time intervals. RSVP-TE is extended to
create a temporal LSP and maintain the status of the temporal LSP.
4.2. Operations Overview
On the ingress of a temporal LSP, a user configures it with a time
interval or a sequence of time intervals. A simple time interval is
a time interval from start time Ta to end time Tb, which may be
represented as [Ta, Tb].
When an LSP is configured with time interval [Ta, Tb], a path
satisfying the constraints for the LSP in the time interval is
computed and the LSP along the path is set up to carry traffic from
Ta to Tb.
For time interval from start time Ta to infinite as end time, it may
be represented as [Ta, INFINITE].
In addition to simple time intervals, there are recurrent time
intervals and elastic time intervals.
A recurrent time interval represents a series of repeated simple time
intervals. It has a simple time interval such as [Ta, Tb], a number
of repeats such as 10 (repeats 10 times), and a repeat cycle/time
such as a week (repeats every week).
Recurrent time interval "[Ta, Tb] repeats n times with repeat cycle
C" represents n+1 simple time intervals as follows:
[Ta, Tb], [Ta+C, Tb+C], [Ta+2C, Tb+2C], . . ., [Ta+nC, Tb+nC]
When an LSP is configured with a recurrent time interval such as
"[Ta, Tb] repeats 10 times with a repeat cycle a week", a path
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satisfying the constraints for the LSP in each of the simple time
intervals (such as 11 simple time intervals) represented by the
recurrent time interval is computed and the LSP along the path is set
up to carry traffic in each of the simple time intervals.
An elastic time interval represents a time period with an elastic
range. It has a simple time interval such as [Ta, Tb] with an
elastic range such as within -P and Q.
Elastic time interval "[Ta, Tb] within -P and Q" means a time period
from (Ta+X) to (Tb+X), where -P <= X <= Q, P and Q is an amount of
time such as 600 seconds.
When an LSP is configured with an elastic time interval such as "[Ta,
Tb] within -P and Q", a path is computed such that the path satisfies
the constraints for the LSP in the time period from (Ta+X) to (Tb+X)
and |X| is the minimum value from -P to Q. That is that [Ta+X, Tb+X]
is the time interval closest to [Ta, Tb] within the elastic range.
The LSP along the path is set up to carry traffic in the time period
from (Ta+X) to (Tb+X).
5. TIME INTERVAL Object
This section presents a few of TIME-INTERVAL objects, which are the
internal representations of time intervals. A Class-Num for the
objects is TBD, which is to be assigned by IANA.
5.1. Absolute TIME INTERVAL Object
The format of an absolute TIME-INTERVAL object body is illustrated
below.
Class-Name: TIME-INTERVAL, Class-Num: TBD, C-Type = 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Start-time: The time LSP starts to carry traffic
o End-time: The time LSP ends carrying traffic
An absolute TIME-INTERVAL object contains a Start-time and an End-
time, representing time interval [Start-time, End-time]. All bits in
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End-time field set to one represents INFINITE. Both of these two
times are the times that are synchronized among all network nodes.
Thus the clocks on all the nodes MUST be synchronized if an absolute
TIME-INTERVAL object is used. The time period represented in an
absolute TIME-INTERVAL object is more accurate.
5.2. Relative TIME INTERVAL Object
The format of a relative TIME-INTERVAL object body is shown below.
Class-Name: TIME-INTERVAL, Class-Num: TBD, C-Type = 2
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start-time-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End-time-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Start-time-length: The time length in seconds from current time
to the time LSP starts to carry traffic
o End-time-length: The time length in seconds from current time
to the time LSP ends carrying traffic
A relative TIME-INTERVAL object contains a Start-time-length and an
End-time-length, which represents time interval below:
[current-time + Start-time-length, current-time + End-time-length]
where current-time is the current local time on a node. All bits in
End-time-length field set to one represents INFINITE.
When a time interval from time Ta to time Tb is configured on a node,
these two time lengths are the time lengths that are computed on the
node using the current local time as follows.
Start-time-length = Ta - current-time;
End-time-length = Tb - current-time;
For a relative TIME-INTERVAL object, the clocks/times on all the
nodes can be different.
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5.3. Recurrent Absolute TIME INTERVAL Object
For a recurrent absolute TIME-INTERVAL object, its body contains a
Start-time, an End-time, a Repeat-time-length, a Options field and a
Number-repeats field. The format of its body is illustrated below:
The Start-time and End-time represents time interval [Start-time,
End-time]. The Repeat-time-length represents a repeat cycle/time,
which is valid if the Options field is set to indicate the way to
repeat is "repeat every Repeat-time-length". The Options field
indicates a way to repeat. The Number-repeats indicates the number
of repeats of time interval [Start-time, End-time].
Class-Name: TIME-INTERVAL, Class-Num: TBD, C-Type = 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Repeat-time-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options | Number-repeats | Reserved(0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Start-time: The time LSP starts to carry traffic.
End-time: The time LSP ends carrying traffic.
Repeat-time-length: The time length in seconds after which LSP
starts to carry traffic again for (End-time - Start-time).
Options: Indicates a way to repeat.
Options = 1: repeat every day;
Options = 2: repeat every week;
Options = 3: repeat every month;
Options = 4: repeat every year;
Options = 5: repeat every Repeat-time-length.
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Number-repeats: The number of repeats. In each of repeats, LSP
carries traffic.
5.4. Recurrent Relative TIME INTERVAL Object
For a recurrent relative TIME-INTERVAL object, the format of its body
is illustrated below. it contains a Start-time-length, an End-time-
length, a Repeat-time-length, a Options field and a Number-repeats
field.
The Start-time-length and End-time-length represents time interval
[current-time + Start-time-length, current-time + End-time-length]
where current-time is a current local time.
The Repeat-time-length represents a repeat cycle/time, which is valid
if the Options field is set to indicate the way to repeat is "repeat
every Repeat-time-length". The Options field indicates a way to
repeat. The Number-repeats indicates the number of repeats of the
time interval above.
Class-Name: TIME-INTERVAL, Class-Num: TBD, C-Type = 4
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start-time-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End-time-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Repeat-time-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options | Number-repeats | Reserved (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Start-time-length: The time length in seconds from a current local
time to the time LSP starts to carry traffic.
End-time-length: The time length in seconds from a current local
time to the time LSP ends carrying traffic.
Repeat-time-length: The time length in seconds after which LSP
starts to carry traffic again for (End-time-length - Start-time-
length).
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Options: Indicates a way to repeat.
Options = 1: repeat every day;
Options = 2: repeat every week;
Options = 3: repeat every month;
Options = 4: repeat every year;
Options = 5: repeat every Repeat-time-length.
Number-repeats: The number of repeats. In each of repeats, LSP
carries traffic.
6. Path Message
A Path message is enhanced to carry the information about a time
interval or a sequence of time intervals through including a time
interval list. The format of the message is illustrated below.
<Path Message> ::= <Common Header> [ <INTEGRITY> ]
[ [<MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>] ...]
[ <MESSAGE_ID> ]<SESSION> <RSVP_HOP> <TIME_VALUES>
[ <EXPLICIT_ROUTE> ]
<LABEL_REQUEST> [ <PROTECTION> ] [ <LABEL_SET> ...]
[ <SESSION_ATTRIBUTE> ] [ <NOTIFY_REQUEST> ]
[ <ADMIN_STATUS> ] [ <POLICY_DATA> ... ]
<sender descriptor> [<S2L sub-LSP descriptor list>]
[<time interval list>]
The time interval list in the message is defined below. It is a
sequence of TIME-INTERVAL objects, each of which describes a time
interval or a series of time intervals.
<time interval list> ::=
<time interval descriptor>
[ <time interval list> ]
<time interval descriptor> ::= <TIME-INTERVAL>
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7. Behaviors for Temporal LSP
To set up a temporal LSP, the ingress of the LSP MUST include the
TIME-INTERVAL objects representing the time intervals configured for
the LSP in the PATH message for the LSP.
In addition, the ingress computes a shortest path satisfying the
constraints for the LSP in each of the time intervals. it MUST
include the ERO for the path in the PATH message for the LSP.
For every node along the path for the LSP, when receiving a PATH
message with TIME-INTERVAL objects, it obtains the time intervals
represented by the objects in the message received and MUST forward
the objects unchanged to the next hop if there is one.
It adds the time intervals into the state for the LSP and checks
whether there is enough bandwidth in each of the time intervals. If
there is, it reserved the bandwidth on the link to the next hop (if
there is a next hop) in each of the time intervals. If there is not,
a PathErr message is returned.
8. Security Considerations
The mechanism described in this document does not raise any new
security issues for the RSVP-TE protocols.
9. IANA Considerations
This section specifies requests for IANA allocation.
10. Acknowledgement
The author would like to thank people for their valuable comments on
this draft.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
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[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>.
[RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
Yasukawa, Ed., "Extensions to Resource Reservation
Protocol - Traffic Engineering (RSVP-TE) for Point-to-
Multipoint TE Label Switched Paths (LSPs)", RFC 4875,
DOI 10.17487/RFC4875, May 2007,
<http://www.rfc-editor.org/info/rfc4875>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003,
<http://www.rfc-editor.org/info/rfc3630>.
11.2. Informative References
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, DOI 10.17487/
RFC3031, January 2001,
<http://www.rfc-editor.org/info/rfc3031>.
Authors' Addresses
Huaimo Chen
Huawei Technologies
Boston, MA
US
Email: huaimo.chen@huawei.com
Mehmet Toy
Verizon
USA
Email: mehmet.toy@verizon.com
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Vic Liu
China Mobile
No.32 Xuanwumen West Street, Xicheng District
Beijing, 100053
China
Email: liu.cmri@gmail.com
Lei Liu
Fijitsu
USA
Email: lliu@us.fujitsu.com
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