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333 73th IETF, CCAMP WG, Minneapolis, MN, USA November 2008 Scope Definition, terminology, measurement techniques, encoding techniques for optical impairments are out side the scope of this document. The document relies on ITU-T recommendations for this purpose (e.g., [G.680]). [RFC4054] provides an overview of some critical optical impairments and the associated routing related issues. Framework document elaborates on how these impairments can be used in the control plane. The draft proposes an RSVP-TE based mechanism to collect and evaluate optical impairments measured or estimated at the optical nodes along the light-path.
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173th IETF, CCAMP WG, Minneapolis, MN, USA73th IETF, CCAMP WG, Minneapolis, MN, USA November November 20082008
RSVP-TE based Impairments Collection Mechanism
Zafar Ali, Roberto Cassata (Cisco Systems) Marco Anisetti, Valerio Bellandi, Ernesto Damiani, Francesco Diana, Umberto Raimondi (University of Milan) T. Otani (KDDI R&D Laboratories)
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Outline
• Scope• Impairments Identification and Collection• Proposed RSVP-TE extensions• Impairments signaling scenarios
33373th IETF, CCAMP WG, Minneapolis, MN, USA73th IETF, CCAMP WG, Minneapolis, MN, USA November 2008 November 2008
Scope
• Definition, terminology, measurement techniques, encoding techniques for optical impairments are out side the scope of this document. The document relies on ITU-T recommendations for this purpose (e.g., [G.680]).
• [RFC4054] provides an overview of some critical optical impairments and the associated routing related issues.
• Framework document elaborates on how these impairments can be used in the control plane.
• The draft proposes an RSVP-TE based mechanism to collect and evaluate optical impairments measured or estimated at the optical nodes along the light-path.
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Motivation
• The proposed technique is suitable for optical networks that suffer of physical dysfunction due the non-ideal optical transmission medium and/or to critical situations (e.g., a fiber cut).
• In these scenario even if every node along the path is connected, the reachability of the end node with an acceptable signal quality is not guaranteed.
• The proposed technique can be used for fault isolation.
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Impairments Collection
• The term impairments refer to real optical measurements or estimates computed using a prediction model.
• Real optical measurements may require mutually exclusive access to hardware to avoid interference, in which case the impairments required a blocking collection type.
• The impairments computed using a prediction model can be collected in a non-blocking fashion.
• Consequently, every optical node resource can be in three states: unlock, lock-requested or lock.
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Optical Impairments Encoding
• Optical Impairments encoding is out side the scope of this document.
• Preliminary encoding presented to ITU Q6 on June 25, 2008 (Munich meeting) as WD6-23
Preliminarily approved by Q6; confirmation requested to Q11. Single source for all protocols dealing with evidence transport.
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• This TLV defines which type of impairments needs to be collected in the Path message.
• E-type (Impairments Type, 8 bits): Impairments identifier encoded as per [WD6-23]. E.g., 0 for Signal power, 1 for OSNR etc.
Impairments Collection Request TLV
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• This TLV records the impairment's values of the LSP defined in the Impairments Collection Request TLV.
• WavelengthID: According to [WD6-23], This field identifies the wavelength. If it is measured/estimated aggregate impairments, this field is set to 0.
• IPv4/IPv6 Address: The address of the Node. • Evidence Value: Estimated or measured evidence value according to
[WD6-23]. E.g., the Signal Optical Power as 32-bit IEEE 754 floating point number, padded as necessary.
Impairments recording TLV
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None Blocking Impairment Collection
PXC1 PXC2
Path Message Path Message Path Message
Resv Message Resv MessageResv Message
Impairments Collection Request TLVImpairments Recording TLV
Free
Impairments Reading
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Administrative Status Object Extension
• We propose and extension to Administrative status object by adding two bits for locking purpose
• Blocking node (B): 1 bit. When set, indicates that locking procedure is proceeding.
• Confirm blocking (C): 1 bit. When set, indicates that the locking procedure is successfully.
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Blocking Impairments Collection: Case I
PXC1 PXC2
B=1C=1R=1
B=1C=1R=1
B=1C=1R=1
B=1C=1R=0
B=1C=1R=0
B=1C=1R=0
Unlock
Locked
Lock Required
All nodes ready for impairments collection
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PXC1 PXC2
B=1C=1R=1
B=1C=0R=1
B=1C=1R=1
B=1C=0R=0
B=1C=0R=0
B=1C=0R=0Unlock
Locked
Lock Required
Blocking Impairments Collection: Case II
Some node(s) blocked by another impairments collection
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Thank You.
