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Re: Request To Publish: draft-ietf-opes-iab-03
2003-10-27 06:31:32
Folks,
please take a very, very careful look at this version of the draft
(draft-ietf-opes-iab-03). In particular, please check out the two
issues marked with 'XXX')
THIS IS THE FINAL DOCUMENT CANDIDATE.
Please post your comments to the mailing before the IETF meeting in
Minneapolis (i.e. before 11/9), so that we can close on the draft in
Minneapolis and issue WGLC shortly after. I'd expect that open issues
get resolved beforehand, so please check it out NOW!!
Thanks,
Markus
Alex Rousskov wrote:
Please publish the attached draft-ietf-opes-iab-03.txt as an OPES
working group Internet Draft.
Thank you,
Alex.
------------------------------------------------------------------------
Open Pluggable Edge Services A. Barbir
Internet-Draft Nortel Networks
Expires: April 26, 2004 A. Rousskov
The Measurement Factory
October 27, 2003
OPES Treatment of IAB Considerations
draft-ietf-opes-iab-03
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at http://
www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 26, 2004.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
IETF Internet Architecture Board (IAB) expressed nine
architecture-level considerations for the Open Pluggable Edge
Services (OPES) framework. This document describes how OPES
addresses those considerations.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Consideration (2.1) 'One-party consent' . . . . . . . . . . . 5
4. Consideration (2.2) 'IP-layer communications' . . . . . . . . 6
5. Notification Considerations . . . . . . . . . . . . . . . . . 8
5.1 Notification versus trace . . . . . . . . . . . . . . . . . . 8
5.2 An example of an OPES trace for HTTP . . . . . . . . . . . . . 9
5.3 Consideration (3.1) 'Notification' . . . . . . . . . . . . . . 10
5.4 Consideration (3.2) 'Notification' . . . . . . . . . . . . . . 12
6. Consideration (3.3) 'Non-blocking' . . . . . . . . . . . . . . 13
7. Consideration (4.1) 'URI resolution' . . . . . . . . . . . . . 14
8. Consideration (4.2) 'Reference validity' . . . . . . . . . . . 15
9. Consideration (4.3) 'Addressing extensions' . . . . . . . . . 16
10. Consideration (5.1) 'Privacy' . . . . . . . . . . . . . . . . 17
11. Consideration 'Encryption' . . . . . . . . . . . . . . . . . . 18
12. Security Considerations . . . . . . . . . . . . . . . . . . . 19
13. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . 20
A. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Normative References . . . . . . . . . . . . . . . . . . . . . 23
Informative References . . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 24
Intellectual Property and Copyright Statements . . . . . . . . 25
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1. Introduction
The Open Pluggable Edge Services (OPES) architecture
[I-D.ietf-opes-architecture], enables cooperative application
services (OPES services) between a data provider, a data consumer,
and zero or more OPES processors. The application services under
consideration analyze and possibly transform application-level
messages exchanged between the data provider and the data consumer.
In the process of chartering OPES, the IAB made recommendations on
issues that OPES solutions should be required to address. These
recommendations were formulated in the form of a specific IAB
considerations document [RFC3238]. In that document, IAB emphasized
that its considerations did not recommend specific solutions and did
not mandate specific functional requirements. Addressing an IAB
consideration may involve showing appropriate protocol mechanisms or
demonstrating that the issue does not apply. Addressing a
consideration does not necessarily mean supporting technology implied
by the consideration wording.
The primary goal of this document is to show that all IAB
recommendations are addressed by OPES, to the extent that those
considerations can be addressed by an IETF working group. The
limitations of OPES working group to address certain aspects of IAB
considerations are also explicitly documented.
There are nine IAB considerations [RFC3238] that OPES has to address.
In the core of this document are the corresponding nine
"Consideration" sections. For each IAB consideration, its section
contains general discussion as well as references to specific OPES
mechanisms relevant to the consideration.
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2. Terminology
This document does not introduce any new terminology but uses
terminology from other OPES documents it quotes.
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3. Consideration (2.1) 'One-party consent'
"An OPES framework standardized in the IETF must require that the use
of any OPES service be explicitly authorized by one of the
application-layer end-hosts (that is, either the content provider or
the client)."[RFC3238]
OPES architecture requires that "OPES processors MUST be consented to
by either the data consumer or data provider application"
[I-D.ietf-opes-architecture]. This requirement alone cannot prevent
consent-less introduction of OPES processors. In
[I-D.ietf-opes-end-comm], the OPES architecture enables concerned
parties to detect unwanted OPES processors by examining OPES traces.
The use of traces in OPES is mandatory.
A tracing mechanism on its own cannot detect processors that are in
violation of OPES specifications. Examples include OPES processors
operating in stealth mode. However, the OPES architecture allows the
use of content signature to verify the authenticity of performed
adaptations. Content signatures is a strong but expensive mechanism
that can detect any modifications of signed content provided that the
content provider is willing to sign the data and that the client is
willing to either check the signature or relay received content to
the content provider for signature verification.
OPES adaptations may include copying and other forms of non-modifying
access to content. These kinds of adaptations cannot be detected by
the above mentioned mechanisms. Thus, "passive" OPES processors can
operate on the content without the data consumer or provider consent.
If presence of such processors is a concern, then content encryption
can be used. A passive processor is no different from a proxy or an
intermediary operating outside of OPES framework. No OPES mechanism
(existing or foreseeable) can prevent non-modifying access to
content.
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4. Consideration (2.2) 'IP-layer communications'
"For an OPES framework standardized in the IETF, the OPES
intermediary must be explicitly addressed at the IP layer by the end
user."[RFC3238]
The OPES architecture requires that "OPES processors MUST be
addressable at the IP layer by the end user (data consumer
application)" [I-D.ietf-opes-architecture]. The IAB and the
architecture documents mention an important exception: addressing the
first OPES processor in a chain of processors is sufficient. That is,
a chain of OPES processors is viewed as a single OPES "system" at the
address of the first chain element.
The notion of a chain is not strictly defined by IAB. For the purpose
of addressing this consideration, a group of OPES processors working
on a given application transaction is considered. Such a group would
necessarily form a single processing chain, with a single "exit" OPES
processor (i.e., the processor that adapted the given message last).
The OPES architecture essentially requires that last OPES processor
to be explicitly addressable at the IP layer by the data consumer
application. The chain formation, including its exit point may depend
on an application message and other dynamic factors such as time of
the day or system load.
Furthermore, if OPES processing is an internal processing step at a
data consumer or a data provider application side, then the last OPES
processor may reside in a private address space and may not be
explicitly addressable from the outside. In such situations, the
processing side must designate an addressable point on the same
processing chain. That designated point may not be, strictly
speaking, an OPES processor, but it will suffice as such as far as
IAB considerations are concerned -- the data consumer application
will be able to address it explicitly at the IP layer and it will
represent the OPES processing chain to the outside world.
Designating an addressable processing point avoids the conflict
between narrow interpretation of the IAB consideration and real
system designs. It is irrational to expect a content provider to
provide access to internal hosts participating in content generation,
whether OPES processors are involved or not. Moreover, providing such
access would serve little practical purpose because internal OPES
processors are not likely to be able to answer any data consumer
queries, being completely out of content generation context. For
example, an OPES processor adding customer-specific information to
XML pages may not understand or be aware of any final HTML content
that the data consumer application receives and may not be able to
map end user request to any internal user identification. Since OPES
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requires the end of the message processing chain to be addressable,
the conflict does not exist. OPES places no requirements on the
internal architecture of data producer systems while requiring the
entire OPES-related content production "system" to be addressable at
the IP layer.
Private Domain | Public Domain | Private Domain
| |
+--------------+ | +-------------+ +--------+
| Data | | | OPES System | |Data |
| Consumer |<--- network -->| with public |<---->|Provider|
| Application | | | IP address | |App |
+--------------+ | +-------------+ +--------+
| |
| |
Figure 1
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5. Notification Considerations
This section discusses how OPES framework addresses IAB Notification
considerations 3.1 and 3.2.
5.1 Notification versus trace
Before specific considerations are discussed, the relationship
between IAB notifications and OPES tracing has to be explained. OPES
framework concentrates on tracing rather than notification. The OPES
Communications specification [I-D.ietf-opes-end-comm] defines "OPES
trace" as information about OPES adaptations that is embedded in an
application message. Thus, OPES trace follows the application message
it traces. The trace is for the recipient of the application message.
Traces are implemented as extensions of application protocols being
adapted and traced.
As opposed to an OPES trace, provider notification (as implied by
IAB) notifies the sender of the application message rather than the
recipient. Thus, notifications propagate in the opposite direction of
traces. Supporting notifications directly would require a new
protocol. Figure 2 illustrates the differences between a trace and
notification from a single application message point of view.
sender --[message A]--> OPES --[message A']--> recipient
^ V [with trace]
| |
+-<-- [notification] ---+
Figure 2
Since notifications cannot be piggy-backed to application messages,
they create new messages and may double the number of messages the
sender has to process. The number of messages that need to be proceed
is larger if several intermediaries on the message path generate
notifications). Associating notifications with application messages
may require duplicating application message information in
notifications and may require maintaining a sender state until
notification is received. These actions increase the performance
overhead of notifications.
The level of available details in notifications versus provider
interest in supporting notification is another concern. Experience
shows that content providers often require very detailed information
about user actions to be interested in notifications at all. For
example, Hit Metering protocol [RFC2227] has been designed to supply
content providers with proxy cache hit counts, in an effort to reduce
cache busting behavior which was caused by content providers desire
to get accurate site "access counts". However, the Hit Metering
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protocol is currently not widely deployed because the protocol does
not supply content providers with information such as client IP
addresses, browser versions, or cookies.
Hit Metering experience is relevant because Hit Metering protocol was
designed to do for HTTP caching intermediaries what OPES
notifications are meant to do for OPES intermediaries. Performance
requirements call for state reduction via aggregation of
notifications while provider preferences call for state preservation
or duplication. Achieving the right balance when two sides belong to
different organizations and have different optimization priorities
may be impossible.
Thus, instead of explicitly supporting notifications at the protocol
level, OPES concentrates on tracing facilities. In essence, OPES
supports notifications indirectly, using tracing facilities. In other
words, the IAB choice of "Notification" label is interpreted as
"Notification assistance" (i.e. making notifications meaningful) and
is not interpreted as a "Notification protocol".
The above concerns call for making notification optional. The OPES
architecture allows for an efficient and meaningful notification
protocol to be implemented in certain OPES environments. For
specific examples, see the "Optional Notification" section in
[I-D.ietf-opes-end-comm].
5.2 An example of an OPES trace for HTTP
The example below illustrates adaptations done to HTTP request at an
OPES processor operated by the client ISP. Both original (as sent by
an end user) and adapted (as received by the origin web server)
requests are shown. The primary adaptation is the modification of
HTTP "Accept" header. The secondary adaptation is the addition of an
"OPES-Via" HTTP extension header [I-D.ietf-opes-http] (XXX: but it is
not OPES-Via, it is OPES-System for now; OPES-Via is probably better
for a few reasons though).
GET /pub/WWW/ HTTP/1.1
Host: www.w3.org
Accept: text/plain
Figure 3
... may be adapted by an ISP OPES system to become:
GET /pub/WWW/ HTTP/1.1
Host: www.w3.org
Accept: text/plain; q=0.5, text/html, text/x-dvi; q=0.8
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OPES-Via: http://www.isp-example.com/opes/?client-hash=1234567
Figure 4
The example below illustrates adaptations done to HTTP response at an
OPES intermediary operated by a Content Distribution Network (CDN).
Both original (as sent by the origin web server) and adapted (as
received by the end user) responses are shown. The primary adaptation
is the conversion from HTML markup to plain text. The secondary
adaptation is the addition of an "OPES-Via" HTTP extension header.
HTTP/1.1 200 OK
Content-Length: 12345
Content-Encoding: text/html
<html><head><h1>Available Documenta...
Figure 5
... may be adapted by a CDN OPES system to become:
HTTP/1.1 200 OK
Content-Length: 2345
Content-Encoding: text/plain
OPES-Via: http://www.cdn-example.com/opes/?site=7654321&service=h2t
AVAILABLE DOCUMENTA...
Figure 6
In the above examples, "OPES-Via" header values contain URLs that may
point to OPES-specific documents such as description of the OPES
operator and its privacy policy. Those documents may be
parameterized to allow for customizations specific to the transaction
being traced (e.g., client or even transaction identifier may be used
to provide more information about performed adaptations). Traced OPES
URLs may be later used to request OPES bypass
[I-D.ietf-opes-end-comm].
5.3 Consideration (3.1) 'Notification'
"The overall OPES framework needs to assist content providers in
detecting and responding to client-centric actions by OPES
intermediaries that are deemed inappropriate by the content
provider."[RFC3238]
OPES tracing mechanisms assist content providers in detecting
client-centric actions by OPES intermediaries. Specifically, a
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compliant OPES intermediary or system notifies a content provider of
its presence by including its tracing information in the application
protocol requests. An OPES system MUST leave its trace
[I-D.ietf-opes-end-comm]. Detection assistance has its limitations.
Some OPES intermediaries may work exclusively on responses and may
not have a chance to trace the request. Moreover, some application
protocols may not have explicit requests (e.g., a content push
service).
OPES tracing mechanisms assist content providers in responding to
client-centric actions by OPES intermediaries. Specifically, OPES
traces MUST include identification of OPES systems and SHOULD include
a list of adaptation actions performed on provider's content. This
tracing information may be included in the application request.
Usually, however, this information will be included in the
application response, an adapted version of which does not reach the
content provider. If OPES end points cooperate, then notification can
be assisted with traces. Content providers that suspect or experience
difficulties can do any of the following:
o Check whether requests they receive pass through OPES
intermediaries. Presence of OPES tracing info will determine that.
This check is only possible for request/response protocols. For
other protocols (e.g., broadcast or push), the provider would have
to assume that OPES intermediaries are involved until proven
otherwise.
o If OPES intermediaries are suspected, request OPES traces from
potentially affected user(s). The trace will be a part of the
application message received by the user software. If involved
parties cooperate, the provider(s) may have access to all the
needed information. Certainly, lack of cooperation may hinder
access to tracing information. To encourage cooperation, data
providers might be able to deny service to uncooperative users.
o Some traces may indicate that more information is available by
accessing certain resources on the specified OPES intermediary or
elsewhere. Content providers may query for more information in
this case.
o If everything else fails, providers can enforce no-adaptation
policy using appropriate OPES bypass mechanisms and/or end-to-end
encryption mechanisms.
OPES detection and response assistance is limited to application
protocols with support for tracing extensions. For example, HTTP
[RFC2616] has such support while DNS over UDP does not.
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5.4 Consideration (3.2) 'Notification'
"The overall OPES framework should assist end users in detecting the
behavior of OPES intermediaries, potentially allowing them to
identify imperfect or compromised intermediaries."[RFC3238]
OPES tracing mechanisms assist end users in detecting OPES
intermediaries. Specifically, a compliant OPES intermediary or system
notifies an end user of its presence by including its tracing
information in the application protocol messages sent to the client.
An OPES system MUST leave its trace [I-D.ietf-opes-end-comm].
However, detection assistance has its limitations. Some OPES systems
may work exclusively on requests and may not have a chance to trace
the response. Moreover, some application protocols may not have
explicit responses (e.g., event logging service).
OPES detection assistance is limited to application protocols with
support for tracing extensions. For example, HTTP [RFC2616] has such
support while DNS over UDP does not.
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6. Consideration (3.3) 'Non-blocking'
"If there exists a "non-OPES" version of content available from the
content provider, the OPES architecture must not prevent users from
retrieving this "non-OPES" version from the content
provider."[RFC3238]
"OPES entities MUST support a bypass feature"
[I-D.ietf-opes-end-comm]. If an application message includes bypass
instructions and an OPES intermediary is not configured to ignore
them, the matching OPES intermediary will not process the message. An
OPES intermediary may be configured to ignore bypass instructions
only if no non-OPES version of content is available. Bypass may
generate content errors since some OPES services may be essential but
may not be configured as such.
Bypass support has limitations similar to the two
notification-related considerations above.
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7. Consideration (4.1) 'URI resolution'
"OPES documentation must be clear in describing these services as
being applied to the result of URI resolution, not as URI resolution
itself."[RFC3238]
"OPES Scenarios and Use Cases" specification
[I-D.ietf-opes-scenarios] documents content adaptations that are in
scope of the OPES framework. Scenarios include adaptations of
requests and responses. These adaptations do not include URI
resolution adaptations. In some environments, it is technically
possible to adapt URIs (and other kinds of identifiers or addresses)
using documented OPES mechanisms. The OPES framework cannot
effectively prohibit any specific adaptations.
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8. Consideration (4.2) 'Reference validity'
"All proposed services must define their impact on inter- and
intra-document reference validity."[RFC3238]
The OPES framework does not propose adaptation services. However,
OPES tracing requirements include identification of OPES
intermediaries and services (for details, see "Notification"
consideration sections in this document). It is required that
provided identification can be used to locate information about the
OPES intermediaries, including the description of impact on reference
validity [I-D.ietf-opes-end-comm] (XXX: check tracing draft for this
requirement).
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9. Consideration (4.3) 'Addressing extensions'
"Any services that cannot be achieved while respecting the above two
considerations may be reviewed as potential requirements for Internet
application addressing architecture extensions, but must not be
undertaken as ad hoc fixes."[RFC3238]
OPES framework does not contain ad hoc fixes. This document in
combination with and other OPES documents should be sufficient to
inform service creators of IAB considerations. If a service does URI
resolution or silently affects document reference validity, the
authors are requested to review service impact on Internet
application addressing architecture and work within IETF on potential
extension requirements. Such actions would be outside of the current
OPES framework.
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10. Consideration (5.1) 'Privacy'
"The overall OPES framework must provide for mechanisms for end users
to determine the privacy policies of OPES intermediaries."[RFC3238]
OPES tracing mechanisms allow end users to identify OPES
intermediaries (for details, see "Notification" consideration
sections in this document). It is required that provided
identification can be used to locate information about the OPES
intermediaries, including their privacy policies.
The term "privacy policy" is not defined in this context (by IAB or
OPES working group). OPES tracing mechanisms allow end users and
content providers to identify an OPES system and/or intermediaries.
It is believed that once an OPES system is identified, it would be
possible to locate relevant information about that system, including
information relevant to requesters perception of privacy policy or
reference validity.
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11. Consideration 'Encryption'
"If OPES is chartered, the OPES working group will also have to
explicitly decide and document whether the OPES architecture must be
compatible with the use of end-to-end encryption by one or more ends
of an OPES-involved session. If OPES was compatible with end-to-end
encryption, this would effectively ensure that OPES boxes would be
restricted to ones that are known, trusted, explicitly addressed at
the IP layer, and authorized (by the provision of decryption keys) by
at least one of the ends."[RFC3238]
The above quoted requirement was not explicitly listed as on of the
IAB considerations, but still needs to be addressed. The context of
the quote implies that the phrase "end-to-end encryption" refers to
encryption along all links of the end-to-end path, with the OPES
intermediaries as encrypting/decrypting participants or hops (e.g.,
encryption between the provider and the OPES intermediaries, and
between the OPES intermediaries and the client).
Since OPES processors are regular hops on the application protocol
path, OPES architecture allows for such encryption, provided the
application protocol being adapted supports it. Hop-by-hop encryption
would do little good for the overall application message path
protection if callout services have to receive unencrypted content.
To allow for complete link encryption coverage, OPES callout protocol
(OCP) supports encryption of OCP connections between an OPES
processor and a callout server via optional (negotiated) transport
encryption mechanisms [I-D.ietf-opes-ocp-core].
For example, TLS encryption [RFC2817] can be used among HTTP hops
(some of which could be OPES processors) and between each OPES
processor and a callout server.
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12. Security Considerations
This document does not define any mechanisms that may be subject to
security considerations. Security considerations for OPES mechanisms
are discussed in corresponding OPES framework documents.
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13. Compliance
This document may be perceived as a proof of OPES compliance with IAB
implied recommendations. However, this document does not introduce
any compliance subjects. Compliance of OPES implementations is
defined in other OPES documents discussed above.
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Appendix A. Change Log
Internal WG revision control ID: $Id: iab-cons.xml,v 1.26 2003/10/27
11:40:33 rousskov Exp $
2003/10/24
* Addressed hop-by-hop encryption concerns mentioned in the IAB
draft.
* Polished IP addressing figure.
* Removed resolved XXXs.
2003/10/01
* Polishing (Abbie Barbir).
2003/09/23
* Added a reference to Optional Notification section of the
ietf-opes-end-comm draft.
* Fixed "Consideration (3.3) Non-blocking" section position.
head-sid15
* Added a figure showing a chain of internal OPES intermediaries
behind a public IP address. Needs more work. More cases?
head-sid14
* Rewrote the Introduction to the IP addressing consideration.
Do NOT explain how IAB considerations, if interpreted literary,
do not satisfy important real-world constraints. Instead, use
the "chain of OPES intermediaries" exception introduced by IAB
itself to show that OPES architecture addresses IAB concerns as
long as the "chain" is defined/formed for a given application
message rather than being a statically configured application
routing table of sorts. IAB had to add the "chain" exception to
cover one of the most obvious real-world usage scenario. We use
the very same exception to cover all usage scenarios we care
about.
* Polished text explaining the differences between tracing and
notification mechanisms.
* Added examples of OPES/HTTP traces.
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* Be careful not to imply that all OPES intermediaries must obey
bypass instructions. Bypass should be ignored when no non-OPES
version of the content exists. Ideally, this may need to be
polished further -- if there is no non-OPES version of the
content, most IAB considerations probably do not apply because
there is really no adaptation, only creation of content (and we
should not restrict content creation).
* Added references to OPES "Communications" draft
[I-D.ietf-opes-end-comm].
head-sid9
* Polished to meet new xml2rfc strict requirements.
head-sid8
* Added unpolished meat for all nine considerations.
* Added Abbie Barbir as an author.
head-sid7
* Initial revision
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Normative References
[I-D.ietf-opes-end-comm]
Barbir, A., "OPES processor and end points
communications", draft-ietf-opes-end-comm-04 (work in
progress), October 2003.
[I-D.ietf-opes-architecture]
Barbir, A., "An Architecture for Open Pluggable Edge
Services (OPES)", draft-ietf-opes-architecture-04 (work in
progress), December 2002.
[I-D.ietf-opes-scenarios]
Barbir, A., "OPES Use Cases and Deployment Scenarios",
draft-ietf-opes-scenarios-01 (work in progress), August
2002.
[RFC3238] Floyd, S. and L. Daigle, "IAB Architectural and Policy
Considerations for Open Pluggable Edge Services", RFC
3238, January 2002.
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Internet-Draft OPES Treatment of IAB Considerations October 2003
Informative References
[RFC2227] Mogul, J. and P. Leach, "Simple Hit-Metering and
Usage-Limiting for HTTP", RFC 2227, October 1997.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2817] Khare, R. and S. Lawrence, "Upgrading to TLS Within HTTP/
1.1", RFC 2817, May 2000.
[I-D.ietf-opes-http]
Rousskov, A. and M. Stecher, "HTTP adaptation with OPES",
draft-ietf-opes-http-00 (work in progress), August 2003.
[I-D.ietf-opes-ocp-core]
Rousskov, A., "OPES Callout Protocol Core",
draft-ietf-opes-ocp-core-01 (work in progress), August
2003.
Authors' Addresses
Abbie Barbir
Nortel Networks
3500 Carling Avenue
Nepean, Ontario
CA
Phone: +1 613 763 5229
EMail: abbieb(_at_)nortelnetworks(_dot_)com
Alex Rousskov
The Measurement Factory
EMail: rousskov(_at_)measurement-factory(_dot_)com
URI: http://www.measurement-factory.com/
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