draft-ietf-ccamp-wson-impairments-05.txt   draft-ietf-ccamp-wson-impairments-06.txt 
Network Working Group Y. Lee Network Working Group Y. Lee
Huawei Huawei
G. Bernstein G. Bernstein
Grotto Networking Grotto Networking
D. Li D. Li
Huawei Huawei
G. Martinelli G. Martinelli
Cisco Cisco
Internet Draft Internet Draft
Intended status: Informational March 9, 2011 Intended status: Informational April 12, 2011
Expires: September 2011 Expires: October 2011
A Framework for the Control of Wavelength Switched Optical Networks A Framework for the Control of Wavelength Switched Optical Networks
(WSON) with Impairments (WSON) with Impairments
draft-ietf-ccamp-wson-impairments-05.txt draft-ietf-ccamp-wson-impairments-06.txt
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Abstract Abstract
As an optical signal progresses along its path it may be altered by As an optical signal progresses along its path it may be altered by
the various physical processes in the optical fibers and devices it the various physical processes in the optical fibers and devices it
encounters. When such alterations result in signal degradation, we encounters. When such alterations result in signal degradation, these
usually refer to these processes as "impairments". These physical processes are usually referred to as "impairments". These physical
characteristics may be important constraints to consider when using a characteristics may be important constraints to consider when using a
GMPLS control plane to support path setup and maintenance in GMPLS control plane to support path setup and maintenance in
wavelength switched optical networks. wavelength switched optical networks.
This document provides a framework for applying GMPLS protocols and This document provides a framework for applying GMPLS protocols and
the PCE architecture to support Impairment Aware Routing and the PCE architecture to support Impairment Aware Routing and
Wavelength Assignment (IA-RWA) in wavelength switched optical Wavelength Assignment (IA-RWA) in wavelength switched optical
networks. networks.
Table of Contents Table of Contents
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4.2.2. Separate Routing, WA, or IV.........................13 4.2.2. Separate Routing, WA, or IV.........................13
4.2.3. Distributed WA and/or IV............................14 4.2.3. Distributed WA and/or IV............................14
4.3. Mapping Network Requirements to Architectures............15 4.3. Mapping Network Requirements to Architectures............15
5. Protocol Implications.........................................17 5. Protocol Implications.........................................17
5.1. Information Model for Impairments........................17 5.1. Information Model for Impairments........................17
5.2. Routing..................................................18 5.2. Routing..................................................18
5.3. Signaling................................................19 5.3. Signaling................................................19
5.4. PCE......................................................19 5.4. PCE......................................................19
5.4.1. Combined IV & RWA...................................19 5.4.1. Combined IV & RWA...................................19
5.4.2. IV-Candidates + RWA.................................20 5.4.2. IV-Candidates + RWA.................................20
6. Security Considerations.......................................22 5.4.3. Approximate IA-RWA + Separate Detailed IV...........21
7. IANA Considerations...........................................22 6. Security Considerations.......................................23
8. References....................................................22 7. IANA Considerations...........................................23
8.1. Normative References.....................................22 8. References....................................................24
8.2. Informative References...................................24 8.1. Normative References.....................................24
9. Acknowledgments...............................................24 8.2. Informative References...................................25
9. Acknowledgments...............................................26
1. Introduction 1. Introduction
Wavelength Switched Optical Networks (WSONs) are constructed from Wavelength Switched Optical Networks (WSONs) are constructed from
subsystems that may include Wavelength Division Multiplexed (WDM) subsystems that may include Wavelength Division Multiplexed (WDM)
links, tunable transmitters and receivers, Reconfigurable Optical links, tunable transmitters and receivers, Reconfigurable Optical
Add/Drop Multiplexers (ROADM), wavelength converters, and electro- Add/Drop Multiplexers (ROADM), wavelength converters, and electro-
optical network elements. A WSON is a wavelength division optical network elements. A WSON is a wavelength division
multiplexed (WDM)-based optical network in which switching is multiplexed (WDM)-based optical network in which switching is
performed selectively based on the center wavelength of an optical performed selectively based on the center wavelength of an optical
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known as linear case where only linear effects are taken into known as linear case where only linear effects are taken into
account. Note that adding or removing an optical signal on the path account. Note that adding or removing an optical signal on the path
should not render any of the existing signals in the network as non- should not render any of the existing signals in the network as non-
viable. For example, one form of non-viability is the occurrence of viable. For example, one form of non-viability is the occurrence of
transients in existing links of sufficient magnitude to impact the transients in existing links of sufficient magnitude to impact the
BER of existing signals. BER of existing signals.
Much work at ITU-T has gone into developing impairment models at this Much work at ITU-T has gone into developing impairment models at this
and more detailed levels. Impairment characterization of network and more detailed levels. Impairment characterization of network
elements may be used to calculate which paths are conformant with a elements may be used to calculate which paths are conformant with a
specified BER for a particular signal type. In such a case, we can specified BER for a particular signal type. In such a case, the
combine the impairment aware (IA) path computation with the RWA impairment aware (IA) path computation can be combined with the RWA
process to permit more optimal IA-RWA computations. Note that the IA process to permit more optimal IA-RWA computations. Note that the IA
path computation may also take place in a separate entity, i.e., a path computation may also take place in a separate entity, i.e., a
PCE. PCE.
D. Detailed Impairment Computation D. Detailed Impairment Computation
This situation is applicable to networks in which impairment effects This situation is applicable to networks in which impairment effects
must be more accurately computed. For these networks, a full must be more accurately computed. For these networks, a full
computation and evaluation of the impact to any existing paths needs computation and evaluation of the impact to any existing paths needs
to be performed prior to the addition of a new path. Currently no to be performed prior to the addition of a new path. Currently no
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From a control plane point of view optical impairments are additional From a control plane point of view optical impairments are additional
constraints to the impairment-free RWA process described in [WSON- constraints to the impairment-free RWA process described in [WSON-
Frame]. In impairment aware routing and wavelength assignment (IA- Frame]. In impairment aware routing and wavelength assignment (IA-
RWA), there are conceptually three general classes of processes to be RWA), there are conceptually three general classes of processes to be
considered: Routing (R), Wavelength Assignment (WA), and Impairment considered: Routing (R), Wavelength Assignment (WA), and Impairment
Validation (estimation) (IV). Validation (estimation) (IV).
Impairment validation may come in many forms, and maybe invoked at Impairment validation may come in many forms, and maybe invoked at
different levels of detail in the IA-RWA process. From a process different levels of detail in the IA-RWA process. From a process
point of view we will consider the following three forms of point of view the following three forms of impairment validation will
impairment validation: be considered:
o IV-Candidates o IV-Candidates
In this case an Impairment Validation (IV) process furnishes a set of In this case an Impairment Validation (IV) process furnishes a set of
paths between two nodes along with any wavelength restrictions such paths between two nodes along with any wavelength restrictions such
that the paths are valid with respect to optical impairments. These that the paths are valid with respect to optical impairments. These
paths and wavelengths may not be actually available in the network paths and wavelengths may not be actually available in the network
due to its current usage state. This set of paths could be returned due to its current usage state. This set of paths could be returned
in response to a request for a set of at most K valid paths between in response to a request for a set of at most K valid paths between
two specified nodes. Note that such a process never directly two specified nodes. Note that such a process never directly
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[Martinelli] and utilizes enhancements to RSVP signaling to carry [Martinelli] and utilizes enhancements to RSVP signaling to carry
accumulated impairment related information. So the following accumulated impairment related information. So the following
conceptual options belong to this category: conceptual options belong to this category:
o RWA + D(IV) - Combined routing and wavelength assignment and o RWA + D(IV) - Combined routing and wavelength assignment and
distributed impairment validation. distributed impairment validation.
o R + D(WA & IV) -- routing separate from a distributed wavelength o R + D(WA & IV) -- routing separate from a distributed wavelength
assignment and impairment validation process. assignment and impairment validation process.
Distributed impairment validation for a prescribed network path Distributed impairment validation for a prescribed network path
requires that the effects of impairments be calculated by approximate requires that the effects of impairments be calculated by approximate
models with cumulative quality measures such as those given in models with cumulative quality measures such as those given in
[G.680]. For such a system to be interoperable the exact encoding of [G.680]. For such a system to be interoperable the exact encoding of
the techniques from [G.680] would need to be agreed upon. the techniques from [G.680] would need to be agreed upon.
If distributed WA is being done at the same time as distributed IV If distributed WA is being done at the same time as distributed IV
then we may need to accumulate impairment related information for all then it is necessary to accumulate impairment related information for
wavelengths that could be used. This is somewhat winnowed down as all wavelengths that could be used. This is somewhat winnowed down as
potential wavelengths are discovered to be in use, but could be a potential wavelengths are discovered to be in use, but could be a
significant burden for lightly loaded high channel count networks. significant burden for lightly loaded high channel count networks.
4.3. Mapping Network Requirements to Architectures 4.3. Mapping Network Requirements to Architectures
Figure 2 shows process flows for three main architectural Figure 2 shows process flows for three main architectural
alternatives to IA-RWA when approximate impairment validation alternatives to IA-RWA when approximate impairment validation
suffices. Figure 3 shows process flows for two main architectural suffices. Figure 3 shows process flows for two main architectural
alternatives when detailed impairment verification is required. alternatives when detailed impairment verification is required.
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This alternative allows separation of approximate impairment This alternative allows separation of approximate impairment
information into a computational entity while still maintaining a information into a computational entity while still maintaining a
high degree of potential optimality and efficiency in IA-RWA; then a high degree of potential optimality and efficiency in IA-RWA; then a
separate computation entity performs detailed impairment validation. separate computation entity performs detailed impairment validation.
Note that detailed impairment estimation is not standardized. Note that detailed impairment estimation is not standardized.
5. Protocol Implications 5. Protocol Implications
The previous IA-RWA architectural alternatives and process flows make The previous IA-RWA architectural alternatives and process flows make
differing demands on a GMPLS/PCE based control plane. In this section differing demands on a GMPLS/PCE based control plane. This section
we discuss the use of (a) an impairment information model, (b) PCE as discusses the use of (a) an impairment information model, (b) PCE as
computational entity assuming the various process roles and computational entity assuming the various process roles and
consequences for PCEP, (c)any needed extensions to signaling, and (d) consequences for PCEP, (c) any needed extensions to signaling, and
extensions to routing. The impacts to the control plane for IA-RWA (d) extensions to routing. The impacts to the control plane for IA-
are summarized in Figure 4. RWA are summarized in Figure 4.
+-------------------+----+----+----------+--------+ +-------------------+----+----+----------+--------+
| IA-RWA Option |PCE |Sig |Info Model| Routing| | IA-RWA Option |PCE |Sig |Info Model| Routing|
+-------------------+----+----+----------+--------+ +-------------------+----+----+----------+--------+
| Combined |Yes | No | Yes | Yes | | Combined |Yes | No | Yes | Yes |
| IV & RWA | | | | | | IV & RWA | | | | |
+-------------------+----+----+----------+--------+- +-------------------+----+----+----------+--------+-
| IV-Candidates |Yes | No | Yes | Yes | | IV-Candidates |Yes | No | Yes | Yes |
| + RWA | | | | | | + RWA | | | | |
+-------------------+----+----+----------+--------+ +-------------------+----+----+----------+--------+
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In term of approximated scenario (see Section 4.1.1. ) the model In term of approximated scenario (see Section 4.1.1. ) the model
defined by [G.680] will apply and routing protocol will need to defined by [G.680] will apply and routing protocol will need to
gather information required for such computation. gather information required for such computation.
In the case of distributed-IV no new demands would be placed on the In the case of distributed-IV no new demands would be placed on the
routing protocol. routing protocol.
5.3. Signaling 5.3. Signaling
The largest impacts on signaling occur in the cases where distributed The largest impacts on signaling occur in the cases where distributed
impairment validation is performed. In this we need to accumulate impairment validation is performed. In this case, it ie necessary to
impairment information as previously discussed. In addition, since accumulate impairment information as previously discussed. In
the characteristics of the signal itself, such as modulation type, addition, since the characteristics of the signal itself, such as
can play a major role in the tolerance of impairments, this type of modulation type, can play a major role in the tolerance of
information will need to be implicitly or explicitly signaled so that impairments, this type of information will need to be implicitly or
an impairment validation decision can be made at the destination explicitly signaled so that an impairment validation decision can be
node. made at the destination node.
It remains for further study if it may be beneficial to include It remains for further study if it may be beneficial to include
additional information to a connection request such as desired egress additional information to a connection request such as desired egress
signal quality (defined in some appropriate sense) in non-distributed signal quality (defined in some appropriate sense) in non-distributed
IV scenarios. IV scenarios.
5.4. PCE 5.4. PCE
In section 4.3. we gave a number of computation architectural In section 4.3. a number of computation architectural alternatives
alternatives that could be used to meet the various requirements and were given that could be used to meet the various requirements and
constraints of section 4.1. Here we look at how these alternatives constraints of section 4.1. Here the focus is how these alternatives
could be implemented via either a single PCE or a set of two or more could be implemented via either a single PCE or a set of two or more
cooperating PCEs, and the impacts on the PCEP protocol. cooperating PCEs, and the impacts on the PCEP protocol.
5.4.1. Combined IV & RWA 5.4.1. Combined IV & RWA
In this situation, shown in Figure 2(a), a single PCE performs all In this situation, shown in Figure 2(a), a single PCE performs all
the computations needed for IA-RWA. the computations needed for IA-RWA.
o TE Database Requirements o TE Database Requirements: WSON Topology and switching
capabilities, WSON WDM link wavelength utilization, and WSON
WSON Topology and switching capabilities, WSON WDM link wavelength impairment information
utilization, and WSON impairment information
o PCC to PCE Request Information
Signal characteristics/type, required quality, source node, o PCC to PCE Request Information: Signal characteristics/type,
destination node required quality, source node, destination node
o PCE to PCC Reply Information o PCE to PCC Reply Information: If the computations completed
If the computations completed successfully then the PCE returns successfully then the PCE returns the path and its assigned
the path and its assigned wavelength. If the computations could wavelength. If the computations could not complete successfully it
not complete successfully it would be potentially useful to know would be potentially useful to know the reason why. At a very
the reason why. At a very crude level we'd like to know if this crude level it is of interest to know if this was due to lack of
was due to lack of wavelength availability or impairment wavelength availability or impairment considerations or a bit of
considerations or a bit of both. The information to be conveyed is both. The information to be conveyed is for further study.
for further study.
5.4.2. IV-Candidates + RWA 5.4.2. IV-Candidates + RWA
In this situation, shown in Figure 2(b), we have two separate In this situation, as shown in Figure 2(b), two separate processes
processes involved in the IA-RWA computation. This requires at two are involved in the IA-RWA computation. This requires two cooperating
cooperating PCEs: one for the Candidates-IV process and another for path computation entities: one for the Candidates-IV process and
the RWA process. In addition, the overall process needs to be another for the RWA process. In addition, the overall process needs
coordinated. This could be done with yet another PCE or we can add to be coordinated. This could be done with yet another PCE or this
this functionality to one of previously defined PCEs. We choose this functionality can be added to one of previously defined entities.
later option and require the RWA PCE to also act as the overall This later option requires the RWA entity to also act as the overall
process coordinator. The roles, responsibilities and information process coordinator. The roles, responsibilities and information
requirements for these two PCEs are given below. requirements for these two entities when instantiated as PCEs are
given below.
RWA and Coordinator PCE (RWA-Coord-PCE): RWA and Coordinator PCE (RWA-Coord-PCE):
Responsible for interacting with PCC and for utilizing Candidates-PCE Responsible for interacting with PCC and for utilizing Candidates-PCE
as needed during RWA computations. In particular it needs to know to as needed during RWA computations. In particular it needs to know to
use the Candidates-PCE to obtain potential set of routes and use the Candidates-PCE to obtain potential set of routes and
wavelengths. wavelengths.
o TE Database Requirements o TE Database Requirements: WSON Topology and switching capabilities
and WSON WDM link wavelength utilization (no impairment
WSON Topology and switching capabilities and WSON WDM link information).
wavelength utilization (no impairment information).
o PCC to RWA-PCE request: same as in the combined case. o PCC to RWA-PCE request: same as in the combined case.
o RWA-PCE to PCC reply: same as in the combined case. o RWA-PCE to PCC reply: same as in the combined case.
o RWA-PCE to IV-Candidates-PCE request o RWA-PCE to IV-Candidates-PCE request: The RWA-PCE asks for a set
of at most K routes along with acceptable wavelengths between
The RWA-PCE asks for a set of at most K routes along with acceptable nodes specified in the original PCC request.
wavelengths between nodes specified in the original PCC request.
o IV-Candidates-PCE reply to RWA-PCE
The Candidates-PCE returns a set of at most K routes along with o IV-Candidates-PCE reply to RWA-PCE: The Candidates-PCE returns a
acceptable wavelengths between nodes specified in the RWA-PCE set of at most K routes along with acceptable wavelengths between
request. nodes specified in the RWA-PCE request.
IV-Candidates-PCE: IV-Candidates-PCE:
The IV-Candidates-PCE is responsible for impairment aware path The IV-Candidates PCE is responsible for impairment aware path
computation. It needs not take into account current link computation. It needs not take into account current link wavelength
wavelength utilization, but this is not prohibited. The utilization, but this is not prohibited. The Candidates-PCE is only
Candidates-PCE is only required to interact with the RWA-PCE as required to interact with the RWA-PCE as indicated above and not the
indicated above and not the PCC. initiating PCC. (Note: RWA-Coord PCE is also a PCC with respect to
the IV-Candidate)
o TE Database Requirements
WSON Topology and switching capabilities and WSON impairment o TE Database Requirements: WSON Topology and switching capabilities
information (no information link wavelength utilization required). and WSON impairment information (no information link wavelength
utilization required).
In Figure 5 we show a sequence diagram for the interactions between Figure 5 shows a sequence diagram for the interactions between the
the PCC, RWA-Coord PCE and IV-Candidates PCE. PCC, RWA-Coord PCE and IV-Candidates PCE.
+---+ +-------------+ +-----------------+ +---+ +-------------+ +-----------------+
|PCC| |RWA-Coord PCE| |IV-Candidates PCE| |PCC| |RWA-Coord PCE| |IV-Candidates PCE|
+-+-+ +------+------+ +---------+-------+ +-+-+ +------+------+ +---------+-------+
...___ (a) | | ...___ (a) | |
| ````---...____ | | | ````---...____ | |
| ```-->| | | ```-->| |
| | | | | |
| |--..___ (b) | | |--..___ (b) |
| | ```---...___ | | | ```---...___ |
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constraints between two nodes (A and Z) for a given signal constraints between two nodes (A and Z) for a given signal
represented either by a specific type or a general class with represented either by a specific type or a general class with
associated parameters. In step (b) the RWA-Coordinating-PCE requests associated parameters. In step (b) the RWA-Coordinating-PCE requests
up to K candidate paths between nodes A and Z and associated up to K candidate paths between nodes A and Z and associated
acceptable wavelengths. In step (c) The IV-Candidates PCE returns acceptable wavelengths. In step (c) The IV-Candidates PCE returns
this list to the RWA-Coordinating PCE which then uses this set of this list to the RWA-Coordinating PCE which then uses this set of
paths and wavelengths as input (e.g. a constraint) to its RWA paths and wavelengths as input (e.g. a constraint) to its RWA
computation. In step (d) the RWA-Coordinating PCE returns the overall computation. In step (d) the RWA-Coordinating PCE returns the overall
IA-RWA computation results to the PCC. IA-RWA computation results to the PCC.
5.4.3. Approximate IA-RWA + Separate Detailed IV
Previously Figure 3 showed two cases where a separate detailed
impairment validation process could be utilized. It is possible to
place the detailed validation process into a separate PCE. Assuming
that a different PCE assumes a coordinating role and interacts with
the PCC it is possible to keep the interactions with this separate
IV-Detailed-PCE very simple.
IV-Detailed-PCE:
o TE Database Requirements: The IV-Detailed-PCE will need optical
impairment information, WSON topology, and possibly WDM link
wavelength usage information. This document puts no restrictions
on the type of information that may be used in these computations.
o Coordinating-PCE to IV-Detailed-PCE request: The coordinating-PCE
will furnish signal characteristics, quality requirements, path
and wavelength to the IV-Detailed-PCE.
o IV-Detailed-PCE to Coordinating-PCE reply: The reply is essential
an yes/no decision as to whether the requirements could actually
be met. In the case where the impairment validation fails it would
be helpful to convey information related to cause or quantify the
failure, e.g., so a judgment can be made whether to try a
different signal or adjust signal parameters.
Figure 6 shows a sequence diagram for the interactions for the
process shown in Figure 3(b). This involves interactions between the
PCC, RWA-PCE (acting as coordinator), IV-Candidates-PCE and the IV-
Detailed-PCE.
In step (a) the PCC requests a path meeting specified quality
constraints between two nodes (A and Z) for a given signal
represented either by a specific type or a general class with
associated parameters. In step (b) the RWA-Coordinating-PCE requests
up to K candidate paths between nodes A and Z and associated
acceptable wavelengths. In step (c) The IV-Candidates-PCE returns
this list to the RWA-Coordinating PCE which then uses this set of
paths and wavelengths as input (e.g. a constraint) to its RWA
computation. In step (d) the RWA-Coordinating-PCE request a detailed
verification of the path and wavelength that it has computed. In step
(e) the IV-Detailed-PCE returns the results of the validation to the
RWA-Coordinating-PCE. Finally in step (f)IA-RWA-Coordinating PCE
returns the final results (either a path and wavelength or cause for
the failure to compute a path and wavelength) to the PCC.
+----------+ +--------------+ +------------+
+---+ |RWA-Coord | |IV-Candidates | |IV-Detailed |
|PCC| | PCE | | PCE | | PCE |
+-+-+ +----+-----+ +------+-------+ +-----+------+
|.._ (a) | | |
| ``--.__ | | |
| `-->| | |
| | (b) | |
| |--....____ | |
| | ````---.>| |
| | | |
| | (c) __..-| |
| | __..---'' | |
| |<--'' | |
| | |
| |...._____ (d) |
| | `````-----....._____ |
| | `````----->|
| | |
| | (e) _____.....+
| | _____.....-----''''' |
| |<----''''' |
| (f) __.| |
| __.--'' |
|<-'' |
| |
Figure 6 Sequence diagram for the interactions between PCC, RWA-
Coordinating-PCE, IV-Candidates-PCE and IV-Detailed-PCE.
6. Security Considerations 6. Security Considerations
This document discusses a number of control plane architectures that This document discusses a number of control plane architectures that
incorporate knowledge of impairments in optical networks. If such incorporate knowledge of impairments in optical networks. If such
architecture is put into use within a network it will by its nature architecture is put into use within a network it will by its nature
contain details of the physical characteristics of an optical contain details of the physical characteristics of an optical
network. Such information would need to be protected from intentional network. Such information would need to be protected from intentional
or unintentional disclosure. or unintentional disclosure.
7. IANA Considerations 7. IANA Considerations
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Authors' Addresses Authors' Addresses
Greg M. Bernstein (ed.)
Grotto Networking
Fremont California, USA
Phone: (510) 573-2237
Email: gregb@grotto-networking.com
Young Lee (ed.) Young Lee (ed.)
Huawei Technologies Huawei Technologies
1700 Alma Drive, Suite 100 1700 Alma Drive, Suite 100
Plano, TX 75075 Plano, TX 75075
USA USA
Phone: (972) 509-5599 (x2240) Phone: (972) 509-5599 (x2240)
Email: ylee@huawei.com Email: ylee@huawei.com
Greg M. Bernstein (ed.)
Grotto Networking
Fremont California, USA
Phone: (510) 573-2237
Email: gregb@grotto-networking.com
Dan Li Dan Li
Huawei Technologies Co., Ltd. Huawei Technologies Co., Ltd.
F3-5-B R&D Center, Huawei Base, F3-5-B R&D Center, Huawei Base,
Bantian, Longgang District Bantian, Longgang District
Shenzhen 518129 P.R.China Shenzhen 518129 P.R.China
Phone: +86-755-28973237 Phone: +86-755-28973237
Email: danli@huawei.com Email: danli@huawei.com
Giovanni Martinelli Giovanni Martinelli
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