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: January 2014 July 3, 2013
RSVP-TE Signaling Extension for Bandwidth availability
draft-long-ccamp-rsvp-te-bandwidth-availability-01.txt
Abstract
Packet switching network usually contains 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 variable bandwidth link by introducing an optional
availability field in RSVP-TE signaling.
Status of this Memo
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This Internet-Draft will expire on January 7, 2009.
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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
6. References .................................................. 7
6.1. Normative References.................................... 7
6.2. Informative References.................................. 8
7. Acknowledgments ............................................. 8
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
SNR Signal-to-noise Ratio
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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.
There are some data communication technologies that allow seamless
change of maximum physical bandwidth. 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 will 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 reduces by 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 data packets may needs 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 the following extension:
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o A new SENDER_TSPEC object is defined which includes multiple
bandwidth profiles with different availability. This object is
an extension on the Ethernet SENDER_TSPEC defined by [RFC6003]
which support multiple bandwidth profile TLVs, but limited in
the scope of Ethernet. The extension uses the object
generically, and amends availability information in the
bandwidth profile TLV.
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 know about the network topology, and calculate
out a 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 bandwidth in a
network, a <bandwidth, availability> requirement list should be
specified for a LSP. Each <bandwidth, availability> pair in the list
means a bandwidth with specified availability is required. The list
could be inherited from the result of service planning for the LSP.
When a PE node initiates a PATH/RESV signaling for setting up the
LSP, the PATH message should carry the <bandwidth, availability>
requirement list as bandwidth request, and the 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.
3. Extension to RSVP-TE Signaling
3.1. SENDER_TSPEC Object
The SENDER_TSPEC object (Class-Num = 12) has the following format:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Class-Specific Information (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Class-Specific Information: 32 bits
This field indicates the specific information for each C-Type.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... ... |
~ Traffic Parameters ~
| ... ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD, 16 bits;
Length: 16 bits;
Profile: 8 bits
This field is defined as a bit vector of binary flags. The
following flags are defined:
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Flag 3 (bit 2): Availability Flag (AF)
When The Flag 3 is set to value 1, there is an availability
sub-TLV included in this Bandwidth Profile 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.
Index: 8 bits
See [RFC6003] section 4.1.
Traffic Parameters:
This field includes the traffic parameters information. The
format is different for different C-Type.
C-Type = IntServ: See [RFC2210];
C-Type = Ethernet: See [RFC6003];
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
SENDER_TSPEC object. Each Bandwidth Profile TLV specifies the
portion of bandwidth request with referred availability requirement.
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The destination nodes check whether it can satisfy the bandwidth
requirement 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 "Traffic
Control Error" and the error value "Bad Tspec value" (see
[RFC2205]).
4. Security Considerations
This document does not introduce new security considerations to the
existing RSVP-TE signaling protocol.
5. IANA Considerations
TBD
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.
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[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
Authors' Addresses
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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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