Network Working Group H. Long
Internet Draft M.Ye
Intended status: Standards Track Huawei Technologies Co., Ltd
G. Mirsky
Ericsson
A Alessandro
Telecom Italia S.p.A
Expires: April 2014 October 18, 2013
RSVP-TE Signaling Extension for Links with Variable Discrete
Bandwidth
draft-long-ccamp-rsvp-te-bandwidth-availability-02.txt
Abstract
Packet switching network may contain links with variable bandwidth,
e.g., copper, radio, etc. The bandwidth of such link is sensitive to
external environment. Availability is typically used for describing
the link during network planning. This document describes an
extension for RSVP-TE signaling for setting up a label switching
path (LSP) in a Packet Switched Network (PSN) network which contains
links with discretely variable bandwidth by introducing an optional
availability field in RSVP-TE signaling.
Status of this Memo
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Table of Contents
1. Introduction ................................................ 3
2. Overview .................................................... 4
3. Extension to RSVP-TE Signaling............................... 4
3.1. SENDER_TSPEC Object..................................... 4
3.1.1. Bandwidth Profile TLV.............................. 5
3.2. FLOWSPEC Object......................................... 6
3.3. Signaling Process....................................... 6
4. Security Considerations...................................... 7
5. IANA Considerations ......................................... 7
5.1 RSVP Objects Class Types................................ 7
5.2 Ethernet Bandwidth Profile TLV ......................... 8
6. References .................................................. 9
6.1. Normative References.................................... 9
6.2. Informative References.................................. 9
7. Acknowledgments ............................................. 9
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 RFC-2119 [RFC2119].
The following acronyms are used in this draft:
RSVP-TE Resource Reservation Protocol-Traffic Engineering
LSP Label Switched Path
PSN Packet Switched Network
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SNR Signal-to-noise Ratio
TLV Type Length Value
PE Provider Edge
LSA Link State Advertisement
1. Introduction
The RSVP-TE specification [RFC3209] and GMPLS extensions [RFC3473]
specify the signaling message including the bandwidth request for
setting up a label switching path in a PSN network.
Some data communication technologies allow seamless change of
maximum physical bandwidth through a set of known discrete values.
For example, in mobile backhaul network, microwave links are very
popular for providing connection of last hops. In case of heavy rain,
to maintain the link connectivity, the microwave link may lower the
modulation level since demodulating lower modulation level need
lower signal-to-noise ratio (SNR). This is called adaptive
modulation technology [EN 302 217]. However, lower modulation level
also means lower link bandwidth. When link bandwidth reduced because
of modulation down-shifting, high priority traffic can be maintained,
while lower priority traffic is dropped. Similarly the cooper links
may change their link bandwidth due to external interference.
The parameter, availability [G.827, F.1703, P.530], is often used to
describe the link capacity during network planning. Assigning
different availability classes to different types of service over
such kind of links provides more efficient planning of link capacity.
To set up a LSP across these links, availability information is
required for the nodes to verify bandwidth satisfaction and make
bandwidth reservation. The availability information should be
inherited from the availability requirements of the services
expected to be carried on the LSP, voice service usually needs ''five
nines'' availability, while non-real time services may adequately
perform at four or three nines availability. Since different service
types may need different availabilities guarantee, multiple
<availability, bandwidth> pairs may be required when signaling.
To fulfill LSP setup by signaling in these scenarios, this document
specifies a new availability sub-TLV as the sub-TLV of Ethernet
bandwidth profiles [RFC6003]. Multiple bandwidth profiles with
different availability can be carried in the SENDER_TSPEC object.
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2. Overview
A PSN tunnel may span one or more links in a network. To setup a
label switching path (LSP), a PE node may collect link information
which is spread in routing message, e.g., OSPF TE LSA message, by
network nodes to get to know about the network topology, and
calculate out an LSP route based on the network topology, and send
the calculated LSP route to signaling to initiate a PATH/RESV
message for setting up the LSP.
In case that there is(are) link(s) with variable discrete bandwidth
in a network, a <bandwidth, availability> requirement list should be
specified for an LSP. Each <bandwidth, availability> pair in the
list means that listed bandwidth with specified availability is
required. The list could be inherited from the results of service
planning for the LSP.
When a PE node initiates a PATH/RESV signaling to set up an LSP, the
PATH message SHOULD carry the <bandwidth, availability> requirement
list as bandwidth request. Intermediate node(s) will allocate the
bandwidth resource for each availability requirement from the
remaining bandwidth with corresponding availability. An error
message may be returned if any <bandwidth, availability> request
cannot be satisfied.
If there is a hop that cannot support the availability sub-TLV, the
availability sub-TLV is ignored, and the requirement will be treated
as the highest availability.
3. Extension to RSVP-TE Signaling
3.1. SENDER_TSPEC Object
The SENDER_TSPEC object (Class-Num = 12) has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Class-Num (12)| C-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Granularity | MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Switching Granularity (SG): 16 bits
See [RFC6003] section 4.
MTU: 16bits
See [RFC6003] section 4.
TLV (Type-Length-Value):
The SENDER_TSPEC object MUST include at least one TLV and MAY
include more than one TLV.
3.1.1. Bandwidth Profile TLV
The Bandwidth Profile TLV has the following format.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Profile | Index | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CIR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CBS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EIR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EBS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 0x02, 16 bits;
Length: 16 bits;
Profile: 8 bits
This field is defined as a bit vector of binary flags. In RFC
6003, the following flags are defined:
Flag 1 (bit 0): Coupling Flag (CF)
Flag 2 (bit 1): Color Mode (CM)
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A new flag is defined in this document:
Flag 3 (bit 2): Availability Flag (AF)
Index: 8 bits
CIR (Committed Information Rate): 32 bits
CBS (Committed Burst Size): 32 bits
EIR (Excess Information Rate): 32 bits
EBS (Excess Burst Size): 32 bits
See [RFC6003] section 4.1.
When the Flag 3 is set to value 1, there is an availability sub-
TLV included in this Bandwidth Profile TLV. When the Flag 3 is set
to value 0, there won't be an availability sub-TLV. The
availability sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Availability |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type (2 octets): TBD
Length (2 octets): 4
Availability (4 octets): a 32-bit floating number describes
availability requirement for this bandwidth request. The value
must be less than 1.
3.2. FLOWSPEC Object
The FLOWSPEC object (Class-Num = 9, Class-Type = TBD) has the same
format as the Ethernet SENDER_TSPEC object.
3.3. Signaling Process
The source node initiates PATH messages including one or more
Bandwidth Profile TLVs with different availability value in the
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SENDER_TSPEC object. Each Bandwidth Profile TLV specifies the
portion of bandwidth request with referred availability requirement.
The destination node checks whether it can satisfy the bandwidth
requirements by comparing each bandwidth requirement inside the
SENDER_TSPEC objects with the remaining link sub-bandwidth resource
with respective availability guarantee when received the PATH
message.
o If all bandwidth requirements can be satisfied, it should
reserve the bandwidth resource from each remaining sub-
bandwidth portion to set up this LSP. Optionally, the higher
availability bandwidth can be allocated to lower availability
request when the lower availability bandwidth cannot satisfy
the request.
o If at least one bandwidth requirement cannot be satisfied, it
should generate PathErr message with the error code "Admission
Control Error" and the error value "Requested Bandwidth
Unavailable" (see [RFC2205]).
4. Security Considerations
This document does not introduce new security considerations to the
existing RSVP-TE signaling protocol.
5. IANA Considerations
IANA maintains registries and sub-registries for RSVP-TE used by
GMPLS. IANA is requested to make allocations from these registries
as set out in the following sections.
5.1 RSVP Objects Class Types
This document introduces two new Class Types for existing RSVP
objects. IANA is requested to make allocations from the "Resource
ReSerVation Protocol (RSVP) Parameters" registry using the "Class
Names, Class Numbers, and Class Types" sub-registry.
Class Number Class Name Reference
------------ ----------------------- ---------
9 FLOWSPEC [RFC2205]
Class Type (C-Type):
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6 Ethernet SENDER_TSPEC [RFC6003]
Class Number Class Name Reference
------------ ----------------------- ---------
12 SENDER_TSPEC [RFC2205]
Class Type (C-Type):
6 Ethernet SENDER_TSPEC [RFC6003]
5.2 Ethernet Bandwidth Profile TLV
IANA maintains a registry of GMPLS parameters called ''Generalized
Multi-Protocol Label Switching (GMPLS) Signaling Parameters''.
IANA has created a new sub-registry called ''Ethernet Bandwidth
Profiles'' to contain bit flags carried in the Ethernet Bandwidth
Profile TLV of the Ethernet SENDER_TSPEC object.
Bits are to be allocated by IETF Standards Action. Bits are numbered
from bit 0 as the low order bit. A new bit flag is as follow:
Bit Hex Description Reference
--- ---- ------------------ -----------
2 0x03 Availability Flag (AF) [This ID]
Sub-TLV types for Ethernet Bandwidth Profiles are to be allocated by
IETF Standard Action. Initial values are as follows:
Type Length Format Description
--- ---- ------------------ -----------
0 - Reserved Reserved value
TBD 4 see Section 3.1 Availability sub-
TLV
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6. References
6.1. Normative References
[RFC2210] Wroclawski, J., ''The Use of RSVP with IETF Integrated
Services'', RFC 2210, September 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
V.,and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC6003] Papadimitriou, D. ''Ethernet Traffic Parameters'', RFC 6003,
October 2010.
[G.827] ITU-T Recommendation, ''Availability performance parameters
and objectives for end-to-end international constant bit-
rate digital paths'', September, 2003.
[F.1703] ITU-R Recommendation, ''Availability objectives for real
digital fixed wireless links used in 27 500 km
hypothetical reference paths and connections'', January,
2005.
[P.530] ITU-R Recommendation,'' Propagation data and prediction
methods required for the design of terrestrial line-of-
sight systems'', February, 2012
[EN 302 217] ETSI standard, ''Fixed Radio Systems; Characteristics
and requirements for point-to-point equipment and
antennas'', April, 2009
6.2. Informative References
[MCOS] Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions
for Differentiated Services-aware Traffic Engineered
LSPs", Work in Progress, June 2006.
7. Acknowledgments
The authors would like to thank Khuzema Pithewan, Lou Berger, Yuji
Tochio, Dieter Beller, and Autumn Liu for their comments on the
document.
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Authors' Addresses
Hao Long
Huawei Technologies Co., Ltd.
No.1899, Xiyuan Avenue, Hi-tech Western District
Chengdu 611731, P.R.China
Phone: +86-18615778750
Email: longhao@huawei.com
Min Ye
Huawei Technologies Co., Ltd.
No.1899, Xiyuan Avenue, Hi-tech Western District
Chengdu 611731, P.R.China
Email: amy.yemin@huawei.com
Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.com
Alessandro D'Alessandro
Telecom Italia S.p.A
Email: alessandro.dalessandro@telecomitalia.it
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