Network Working Group H. Long
Internet Draft M.Ye
Intended status: Standards Track Huawei Technologies Co., Ltd
Expires: August 2013 February 18, 2013
RSVP-TE Signaling Extension for Bandwidth availability
draft-long-ccamp-rsvp-te-bandwidth-availability-00.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 LSP in
a PSN network which contains variable bandwidth link by introducing
an optional availability field in RSVP-TE signaling.
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Table of Contents
1. Introduction ................................................ 2
2. Extension to RSVP-TE Signaling............................... 3
3. Extension to Routing Protocol................................ 6
4. Security Considerations...................................... 8
5. IANA Considerations ......................................... 8
6. References .................................................. 8
6.1. Normative References.................................... 8
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].
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.
In some networks, there may be some links with variable 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 format since demodulating lower modulation format need
lower signal-to-noise ratio (SNR). This is called adaptive
modulation technology. However, lower modulation format also means
lower link bandwidth. Similarly the cooper links may change their
link bandwidth due to external interference.
The parameter, availability [G.827, F.1703], is often used to
describe the link capacity during network planning. A link may
provide different bandwidth for different availability requirement.
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To set up a LSP across such kind of 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. Since different service types may
need different availabilities guarantee, multiple <availability,
bandwidth> pairs may be required to be signaled. In addition, for
the routing computation, the availability information should also be
provided with bandwidth resource information.
To fulfill LSP setup by signaling in these scenarios, this document
specifies the following extensions:
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.
o An extension on Interface Switching Capacity Descriptor (ISCD)
[RFC4202] for availability information support in routing
signaling. The extension reuses the reserved field in the ISCD
and also introduces an optional availability sub-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 by network nodes, and calculate
out a LSP route, and initiate a PATH/RESV signaling 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.
A node which has link(s) with variable bandwidth attached should
contain a similar <bandwidth, availability> information list in its
routing messages. The list provides the information that how much
bandwidth a link can support for a specified availability. This
information is used for path calculation by the PE node(s).
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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 remained 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:
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.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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:
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.
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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 sender 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.
The receiving nodes check whether it can satisfy the bandwidth
requirement by comparing each bandwidth requirement inside the
SENDER_TSPEC objects with the unallocated link bandwidth resource
with respective availability guarantee.
o If all bandwidth requirements can be satisfied, it should
allocate the bandwidth resource from each unallocated bandwidth
portion for this LSP.
o If at least one bandwidth requirement cannot be satisfied, it
should generate PathErr messages.
4. Extension to Routing Protocol
4.1. Interface Switching Capacity Descriptor
The Interface Switching Capacity Descriptor (ISCD) sub-TLV [RFC 4203]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Cap | Encoding | AI | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Switching Capacity Information ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD, 16 bits;
Length: 16 bits;
AI: ISCD Availability sub-TLV index, 8 bits
This field is the index of availability sub-TLV for this ISCD
sub-TLV.
4.2. ISCD 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Availability Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD, 16 bits;
Length: 16 bits;
Index: 8 bits
This field is the index of this availability sub-TLV,
referred by the AI field of the ISCD sub-TLV.
Availability Information: 32 bits
This field is a 32-bit IEEE floating point number which
describes the availability guarantee of the switching
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capacity in the ISCD object which has the AI value equal to
Index of this sub-TLV. The value must be less than 1.
5. Security Considerations
This document does not introduce new security considerations to the
existing RSVP-TE and OSPF signaling protocols.
6. IANA Considerations
TBD
7. References
7.1. 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.
[RFC4202] Kompella, K. and Rekhter, Y. (Editors), "Routing
Extensions in Support of Generalized Multi-Protocol Label
Switching (GMPLS)", RFC 4202, October 2005.
[RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, October 2005.
[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.
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7.2. 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.
8. Acknowledgments
Authors' Addresses
Hao Long
Huawei Technologies Co., Ltd.
No.1899, Xiyuan Avenue, Hi-tech Western District
Chengdu 611731, P.R.China
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
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