Internet Engineering Task Force C. Chung
Internet-Draft A. Kasyanov
Intended status: Informational J. Livingood
Expires: September 30, 2010 N. Mody
Comcast
B. Van Lieu
Unaffiliated
March 29, 2010
Example of an ISP Web Notification System
draft-livingood-web-notification-05
Abstract
The objective of this document is to describe one method of providing
notifications to web browsers that has been deployed by Comcast, an
Internet Service Provider (ISP). Such a notification system can be
used by an ISP to provide near-immediate notifications to their
users, such as to warn them that their traffic exhibits patterns that
are indicative of malware or virus infection, for example. There are
other proprietary systems that can perform such notifications but
these systems utilize Deep Packet Inspection (DPI) technology. This
document describes one example of a system that does not rely upon
DPI, and is instead based in open standards and open source
applications. While the system described herein is in some ways
specific to the Data-Over-Cable Service Interface Specifications
(DOCSIS) networks used by most cable-based broadband ISPs, components
and concepts described in this document could generally be applied to
many different types of networks.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
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The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on September 30, 2010.
Copyright Notice
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Table of Contents
1. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. High-Level Design of the System . . . . . . . . . . . . . . . 4
4. Design Requirements . . . . . . . . . . . . . . . . . . . . . 5
4.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Web Proxy . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. ICAP Server . . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Messaging Service . . . . . . . . . . . . . . . . . . . . 7
5. Functional Overview . . . . . . . . . . . . . . . . . . . . . 7
5.1. Functional Components Described . . . . . . . . . . . . . 7
5.2. Functional Diagram . . . . . . . . . . . . . . . . . . . . 9
6. High Level Communication Flow . . . . . . . . . . . . . . . . 9
7. Communication Between Web Proxy and ICAP Server . . . . . . . 11
8. End-to-End Web Notification Flow . . . . . . . . . . . . . . . 11
8.1. Step-by-Step Description of the End-to-End Web
Notification Flow . . . . . . . . . . . . . . . . . . . . 12
8.2. Diagram of the End-to-End Web Notification Flow . . . . . 13
9. Example HTTP Headers and JavaScript for a Web Notification . . 14
10. Deployment Considerations . . . . . . . . . . . . . . . . . . 16
11. Security Considerations . . . . . . . . . . . . . . . . . . . 17
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
14.1. Normative References . . . . . . . . . . . . . . . . . . . 17
14.2. Informative References . . . . . . . . . . . . . . . . . . 19
Appendix A. Document Change Log . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Requirements Language
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].
2. Introduction
Internet Service Providers (ISPs) have a need for a system that is
capable of communicating with customers in a nearly immediate manner,
to convey critical service notices such as warnings concerning likely
malware infection. Given the prevalence of the web browser as the
predominant client software in use by Internet users, the web browser
is an ideal vehicle for providing notifications. This document
describes a system that has been deployed by Comcast, a broadband
ISP, to provide near-immediate notifications to web browsers. This
type of system is also designed to provide a non-intrusive, though
obvious, notification to a user's web browser.
In evaluating potential solutions, most commercially available
systems were either proprietary and/or utilized inline-based Deep
Packet Inspection (DPI) technology. Other ISPs may also desire to
use a system based on open standards, non-proprietary software, and
which does not require the use of DPI, which is one of the
motivations for producing this document. While the system described
herein is specific to the Data-Over-Cable Service Interface
Specifications (DOCSIS, [CableLabs DOCSIS]) networks used by most
cable-based broadband ISPs, components and concepts described in this
document can generally be applied to many different types of
networks.
3. High-Level Design of the System
The web notification system design is based on the use of the
Internet Content Adaptation Protocol [RFC3507]. The design uses open
source applications such as Squid Web Proxy, GreasySpoon ICAP server,
and Apache Tomcat. The ICAP protocol allows for message
transformation or adaptation. An ICAP client passes a HyperText
Transport Protocol (HTTP, [RFC2616]) response to an ICAP server for
content adaption. The ICAP Server in turn responds back to the
client with the HTTP response containing the notification message.
Message modification itself may then be provided via either a HTTP
request or HTTP response. However, for the specific system described
in this document, only the HTTP response is modified, by using the
'respmod' method defined in Section 3.2 of [RFC3507].
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4. Design Requirements
This section describes all of the requirements taken into
consideration for the design of this system.
4.1. General
REQ1: TCP Port 80: The system should provide notifications via TCP
port 80, the well-known port for HTTP traffic.
REQ2: Whitelisting: It is possible that the HyperText Markup
Language (HTML, [RFC1866]) or JavaScript [RFC4329] used for
notifications may cause problems while accessing a particular
website. Therefore, such a system should be capable of using
a whitelist of website Uniform Resource Indicators (URIs,
[RFC2396]) or Fully Qualified Domain Named (FQDNs, Section
5.1 of [RFC1035]) that conflict with the system, to instruct
the system to not provide a notifications related to certain
sites, in order to reduce any errors or unexpected results.
REQ3: Instant Messaging (IM): Some IM clients use TCP port 80 in
their communications, often as an alternate port when
standard, well-known ports do not work. This system should
not conflict with or cause unexpected results for IM clients
(or any other client types).
REQ4: Handling of Active Sessions: To the extent that a web
notification system must temporarily route TCP port 80
traffic in order to provide a notification, previously
established TCP port 80 sessions should not be disrupted and
should be routed to the proxy layer.
REQ5: No TCP Resets: The use of TCP resets has been widely
criticized, both in the Internet community generally as well
as in [RFC3360]. As such, except for the case of
unintentional errors, the use of TCP resets must be avoided.
REQ6: Non-Disruptive: The web notification system should not
disrupt the end user experience, such as causing significant
clients errors.
REQ7: Notification Acknowledgement: Once a user responds and
acknowledges a notification, the notification should
immediately stop.
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REQ8: Non-Modification of Content: Such a system should not
significantly alter the content of the HTTP response from any
website the user is accessing.
REQ9: Unexpected Content: The system should transparently handle
traffic for which it cannot provide a web notification.
Thus, widely varying content should be expected, and all such
unexpected traffic should be able to be handled by the system
without generating errors or unexpected results.
REQ10: No Caching: Web content must not be cached by the system.
REQ11: No Advertising Replacement or Insertion: The system must not
be used to replace any advertising provided by a website, or
insert advertising into websites where none was intended by
the owner of a given website.
4.2. Web Proxy
REQ12: Open-Source Software: The system should use an open source
web proxy server, such as Squid. (While it is possible to
use any web proxy, the use of open source, and openly
documented software is recommended.)
REQ13: ICAP Client: The web proxy server should have an integrated
ICAP client.
REQ14: Access Control: Access to the proxy should be limited
exclusively to the IP addresses of users for which
notifications are intended, and only for limited periods of
time. Furthermore, if a Session Management Broker (SMB) is
utilized, as described in Section 5.1 below, then the proxy
should restrict access only to the address of the SMB.
4.3. ICAP Server
REQ15: Request and Response Support: The system should support both
request and response adaptation.
REQ16: Consistency: The system must be able to consistently provide
a specific notification.
REQ17: Multiple Notification Types: The system must be able to
provide many different types of notifications.
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REQ18: Simultaneous Differing Notifications: The system must be able
to simultaneously serve multiple notifications, including
notifications of varying types, to different users. As a
result, User A should be able to get the notification
intended specifically for User A, at the same time that User
B receives an entirely different notification, which was
intended specifically for User B.
4.4. Messaging Service
REQ19: Messaging Service: The Messaging Service, as described in
Section 5.1 below caches the notifications for each specific
user. Thus, by caching the notification messages, the system
may provide notifications without significantly affecting the
web browsing experience of the user.
REQ20: Process Acknowledgements: The Messaging Service should
process acknowledgements to properly remove entries from the
cache and forward acknowledgements to the Messaging Service.
REQ21: Ensure Notification Targeting Accuracy: The Messaging Service
must ensure that notifications are presented to the intended
users.
REQ22: Keep Records for Customer Support: The Messaging Service
should maintain some type of record that a notification has
been presented and/or acknowledged, in case a user inquires
with customer support personnel.
5. Functional Overview
This section defines the various core functional components of the
system. These components are then shown in a diagram to describe how
the various components are linked and relate to one another.
5.1. Functional Components Described
Please note that when a specific software package is cited below, it
is but one example of a possible selection for each component and
should not be considered the only possible option. Though this
accurately list describes the initial software packages used by the
system described herein, those selections are subject to change for a
variety of reasons.
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5.1.A. Web Proxy: The system uses Squid Proxy, an open source web
proxy application in wide use, and one which supports an
integrated ICAP client.
5.1.B. ICAP Server: This should be an open source application
capable of supporting content adaptation in both request and
response modes. The ICAP Server retrieves the notifications
from the Messaging service cache when content adaption is
needed. The initial version of this system uses GreasySpoon,
an open source application.
5.1.C. Customer Database: The Customer Database holds the user
information including the notifications setup for each user.
The database may also hold status of which users were
notified and users pending notification.
5.1.D. Messaging Service: This is a process engine that retrieves
specific web notification messages from a catalog of possible
notifications. When a notification for a specific user is
not in cache, the process retrieves this information from the
Customer Database and populates the cache for a specific
period of time. The initial version of this service uses
Apache Tomcat, an open source application.
5.1.E. Session Management Broker: A Load Balancer (LB) with a
customized layer 7 inspection policy is used to differentiate
between HTTP and non-HTTP traffic on TCP port 80. The SMB
functions as a full stateful TCP proxy with the ability to
forward packets from existing TCP sessions that do not exist
in the internal session table. New HTTP sessions are load
balanced to the web proxy layer either transparently or using
source Network Address Translation (NAT [RFC1631]) from the
SMB, with additional layer 7 inspection as needed. Non-HTTP
traffic for established TCP sessions not in the SMB session
table is simply forwarded to the destination transparently
via the TCP proxy layer.
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5.2. Functional Diagram
+--------+ +------------+ +----------+
| ICAP | <----> | Messaging | <----> | Customer |
| Server | | Service | | Database |
+--------+ +------------+ +----------+
^
| +----------+
| | |
| +-------> | Internet | <-------+
| | | | |
| | +----------+ |
| | ^ |
v v | |
+----------+ v v
|+--------+| +-------+ +--------+
|| ICAP || <----> | SMB | <---> | Access |
|| Client || +-------+ | Router |
|+--------+| +--------+
|| SQUID || ^
|| Proxy || |
|+--------+| v
+----------+ +----------+
| Network |
| Element* |
+----------+
^
|
v
+------+
| PC |
+------+
* An access network element, such as a Cable Modem Termination
System (CMTS).
Figure 1: Web Notification System - Functional Components
6. High Level Communication Flow
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6.A. Setup Differentiated Services (DiffServ): Using DiffServe
[RFC2474] [RFC2475] [RFC2597] [RFC3140] [RFC3246] [RFC3260]
[RFC4594], set a policy to direct TCP port 80 traffic to the
web notification system's web proxy.
6.B. Session Management: TCP port 80 packets are routed to a Session
Management Broker which distinguishes between HTTP or non-HTTP
traffic and between new and existing sessions. HTTP packets
are forwarded to the web proxy by the SMB. Non-HTTP packets
such as instant messaging (IM) traffic are forwarded to a TCP
proxy layer for routing to destination or the SMB operates as
the full TCP proxy and forwards the non-HTTP packets to the
destination. Pre-established TCP sessions on port 80 are
identified by the SMB and forwarded with no impact.
6.C. Web Proxy Forwards Request: The web proxy forwards the HTTP
request on to the destination site, a web server, as a web
proxy normally would do.
6.D. On Response, Send Message to ICAP Server: When the HTTP
response is received from the destination server, the web proxy
sends a message to the ICAP server for the web notification.
6.E. Messaging Service: The Messaging Service should respond with
appropriate notification content or null response if
notification is not cached.
6.F. ICAP Server Responds: The ICAP server responds and furnishes
the appropriate content for the web notification to the web
proxy.
6.G. Web Proxy Sends Response: The web proxy then forwards the HTTP
response to the client web browser containing the web
notification.
6.H. User Response: The user observes the web notification, and
clicks an appropriate option, such as: OK/acknowledged, snooze/
remind me later, etc.
6.I. More Information: Depending upon the notification, the user may
be provided with more information. Using the example of a web
notification to a user explaining that it is highly likely that
they have been infected with a virus or malware, the user may
click an acknowledgement that indicates that clicking that will
take them to a page with information about virus/malware
scanning and remediation.
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6.J. Turn Down DiffServ: Once the notification transaction has
completed, remove any special DiffServ settings.
7. Communication Between Web Proxy and ICAP Server
+------------+
| www URI |
+------------+
^ |
(2)| |(3)
| v
+--------+ (4) +--------+ (4) +--------+
| |------------>| |------------>| |
| | (5) | | (5) | |
| Proxy |<------------| ICAP |<------------| ICAP |
| Module | (6) | Client | (6) | Server |
| |------------>| |------------>| |
| | (7) | | (7) | |
| |<------------| |<------------| |
+--------+ +--------+ +--------+
^ |
(1)| |(8)
| v
+------------+ (9) +------------+
| |----------------------------->| |
| Browser | (10) | Web Server |
| |<-----------------------------| |
+------------+ +------------+
(1) - HTTP GET (TCP 80)
(2) - Proxy HTTP GET (TCP 80)
(3) - HTTP 200 OK w/ Response
(4) - ICAP RESPMOD
(5) - ICAP 200 OK
(6) - TCP Stream - Encapsulate Header
(7) - ICAP 200 OK Insert Message
(8) - HTTP 200 OK w/ Response + Message Frame
(9) - HTTP GET for Message
(10) - HTTP 200 w/ Message Content
Figure 2: Communication Between Web Proxy and ICAP Server
8. End-to-End Web Notification Flow
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8.1. Step-by-Step Description of the End-to-End Web Notification Flow
8.1.1. Policy-Based Routing
1. TCP port 80 packets from the user that needs to be notified may
be routed to the Web Proxy via policy based routing.
2. Packets are forwarded to the Session Management Broker, which
establishes a session with the Web Proxy and routes the packets
to the Web Proxy.
8.1.2. Web Proxy
1. The user's HTTP request is directed to the Web Proxy.
2. The Web Proxy receives HTTP traffic and retrieves content from
the requested web site.
3. The Web Proxy receives the response and forwards it to the ICAP
Server for response adaptation.
4. The ICAP Server checks the HTTP content in order to determine
whether notification message can be inserted.
5. The ICAP Server initiates a request to the Messaging Service
cache process with the IP address of the user.
6. If a notification message for the user exists then the
appropriate notification is cached on the Messaging Service.
The Messaging Service then returns the appropriate notification
content to the ICAP Server.
7. Once the notification message is retrieved from Messaging
Service cache the ICAP server may insert the notification
message in the HTTP response body without altering or modifying
the original content of the HTTP response.
8. The ICAP Server then sends the response back to the Web Proxy,
which in turn forwards the HTTP response back to the browser.
9. If the user's IP address is not found or provisioned for a
notification message, then the ICAP Server should return a '204
No Modifications Needed' response to the ICAP Client as defined
in section 4.3.3 of [RFC3507]. As a result, the user will not
receive any web notification message.
10. The user observes the web notification, and clicks an
appropriate option, such as: OK/acknowledged, snooze/ remind me
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later, etc.
8.2. Diagram of the End-to-End Web Notification Flow
The two figures below show the communications flow from the Web
Browser, through the Web Notification System.
The first figure below illustrates what occurs when a notification
request cannot be inserted because the notification type for the
user's IP address is not cached in the Messaging Service.
ICAP ICAP Message Customer
Browser Proxy Client Server Service Internet DB
| HTTP | | | | | |
| GET | Proxy | | | | |
+------->| Request | | | | |
| +---------|---------|--------|------->| |
| | | | | 200 OK | |
| |<--------|---------|--------|--------+ |
| | ICAP | | | | |
| | RESPMOD | ICAP | | | |
| +-------->| RESPMOD | Check | | |
| | +-------->| Cache | | |
| | | | for IP | | |
| | | | Match | | |
| | | +------->| | |
| | | | Cache | | |
| | | | Miss | | |
| | | |<-------+ Request| |
| | | 204 No | | Type | |
| | | Modif. | +--------|------->|
| | | Needed | | | |
| | No |<--------+ | | Type |
| | Insert | | | |Returned|
| 200 OK |<--------+ | |<-------|--------+
| w/o | | | | | |
| Insert | | | | | |
|<-------+ | | | | |
| | | | | | |
Figure 3: End-to-End Web Notification Flow - With Cache Miss
The figure below illustrates what occurs when a notification request
for the user's IP address is cached in the Messaging Service.
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ICAP ICAP Message Customer
Browser Proxy Client Server Service Internet DB
| HTTP | | | | | |
| GET | Proxy | | | | |
+------->| Request | | | | |
| +---------|---------|--------|------->| |
| | | | | 200 OK | |
| |<--------|---------|--------|--------+ |
| | ICAP | | | | |
| | RESPMOD | ICAP | | | |
| +-------->| RESPMOD | Check | | |
| | +-------->| Cache | | |
| | | | for IP | | |
| | | | Match | | |
| | | +------->| | |
| | | | Cache | | |
| | | | Hit | | |
| | | Insert |<-------+ | |
| | Return | Type | | | |
| | 200 OK |<--------+ | | |
| | with | | | | |
| | Insert | | | | |
| 200 OK |<--------+ | | | |
| w/ | | | | | |
| Notify | | | | | |
|<-------+ | | | | |
| | | | | | |
Figure 4: End-to-End Web Notification Flow - With Cache Hit
9. Example HTTP Headers and JavaScript for a Web Notification
The figure below shows an example of a normal HTTP GET request from
the user's web browser to www.example.com, a web server on the
Internet.
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------------------------------------------------------------------------
1. HTTP Get Request to www.example.com
------------------------------------------------------------------------
http://www.example.com/
GET / HTTP/1.1
Host: www.example.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.14)
Gecko/20080404 Firefox/2.0.0.14
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Pragma: no-cache
------------------------------------------------------------------------
Figure 5: Example HTTP Headers for a Web Notification - HTTP Get
In the figure below, the traffic is routed via the Web Proxy, which
communicates with the ICAP Server and returns the response from
www.example.com. In this case that response is a 200 OK, with the
desired notification message inserted.
------------------------------------------------------------------------
2. Response from www.example.com via PROXY
------------------------------------------------------------------------
HTTP/1.x 200 OK
Date: Thu, 08 May 2008 16:26:29 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT
Etag: "b80f4-1b6-80bfd280"
Accept-Ranges: bytes
Content-Length: 438
Connection: close
Content-Type: text/html; charset=UTF-8
Age: 18
X-Cache: HIT from localhost.localdomain
Via: 1.0 localhost.localdomain (squid/3.0.STABLE5)
Proxy-Connection: keep-alive
------------------------------------------------------------------------
Figure 6: Example HTTP Headers for a Web Notification - HTTP Response
The figure below shows an example of the web notification content
inserted in the 200 OK response, in this example JavaScript code.
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------------------------------------------------------------------------
3. Example of JavaScript containing Notification Insertion
------------------------------------------------------------------------
<!--all elements used in a notification should have css properties
defined to avoid unwanted inheritance from parent page-->
<style type="text/css">
#example {
position: absolute; left: 100px; top: 50px;
z-index: 9999999; height: auto; width: 550px;
padding: 10px;
border: solid 2px black;
background-color:#FDD017;
opacity: 0.8; filter: alpha(opacity = 80);
}
</style>
<script language="javascript" type="text/javascript">
// ensure that content is not part of an iframe
if (self.location == top.location) {
// this is a floating div with 80% transparency
document.write('<div id="example" name="example">');
document.write('<h2>IMPORTANT MESSAGE</h2>');
document.write('<p>Lorem ipsum dolor sit amet, consecteteur ');
document.write('adipisicing elit, sed do eiusmod tempor ');
document.write('incididunt ut labore et dolore magna aliqua. ');
document.write('Ut enim ad minim veniam, quis nostrud ');
document.write('exercitation ullamco laboris nisi ut aliquip ex ');
document.write('ea commodo consequat.');
document.write('</div>');
}</script>
------------------------------------------------------------------------
Figure 7: Example JavaScript Used in a Web Notification
10. Deployment Considerations
The components of the web notification system should be distributed
throughout the network and close to end users. This ensures that the
routing performance and the user's web browsing experience remains
acceptable. It is also recommended that a HTTP-aware load balancer
is used in each datacenter where servers are located, so that traffic
can be spread across N+1 servers and the system can be easily scaled
out.
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11. Security Considerations
This web notification system was conceived in order to provide an
additional method of notifying ISP customers that their computer was
infected with malware. Depending upon the nature of the alert
contained in the web notification, such as the malware alert, users
could fear that it is some kind of phishing attack. As a result,
care should be taken with the text and any links contained in the web
notification itself. For example, the ISP may find it best to
provide a general URI or a telephone number. In contrast to that,
the ISP should NOT ask for login credentials or for someone to follow
a link in the web notification in order to change their password
since these are common phishing techniques. Finally, care should be
taken to provide confidence that the web notification is valid and
from a trusted party, and/or that the user has an alternate method of
checking the validity of the web notification.
12. IANA Considerations
There are no IANA considerations in this document.
NOTE TO RFC EDITOR: PLEASE REMOVE THIS NULL SECTION PRIOR TO
PUBLICATION.
13. Acknowledgements
The authors wish to thank Alissa Cooper for her review of and
comments on the document, as well as others who reviewed the
document.
14. References
14.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC1631] Egevang, K. and P. Francis, "The IP Network Address
Translator (NAT)", RFC 1631, May 1994.
[RFC1866] Berners-Lee, T. and D. Connolly, "Hypertext Markup
Language - 2.0", RFC 1866, November 1995.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, December 1998.
[RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
"Assured Forwarding PHB Group", RFC 2597, June 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
February 2000.
[RFC2915] Mealling, M. and R. Daniel, "The Naming Authority Pointer
(NAPTR) DNS Resource Record", RFC 2915, September 2000.
[RFC3140] Black, D., Brim, S., Carpenter, B., and F. Le Faucheur,
"Per Hop Behavior Identification Codes", RFC 3140,
June 2001.
[RFC3246] Davie, B., Charny, A., Bennet, J., Benson, K., Le Boudec,
J., Courtney, W., Davari, S., Firoiu, V., and D.
Stiliadis, "An Expedited Forwarding PHB (Per-Hop
Behavior)", RFC 3246, March 2002.
[RFC3260] Grossman, D., "New Terminology and Clarifications for
Diffserv", RFC 3260, April 2002.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.
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[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Protocol (SIP): Locating SIP Servers", RFC 3263,
June 2002.
[RFC3507] Elson, J. and A. Cerpa, "Internet Content Adaptation
Protocol (ICAP)", RFC 3507, April 2003.
[RFC4329] Hoehrmann, B., "Scripting Media Types", RFC 4329,
April 2006.
[RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration
Guidelines for DiffServ Service Classes", RFC 4594,
August 2006.
14.2. Informative References
[CableLabs DOCSIS]
CableLabs, "Data-Over-Cable Service Interface
Specifications", CableLabs Specifications Various DOCSIS
Reference Documents, <http://www.cablelabs.com/
specifications/archives/docsis.html>.
[RFC3360] Floyd, S., "Inappropriate TCP Resets Considered Harmful",
BCP 60, RFC 3360, August 2002.
Appendix A. Document Change Log
[RFC Editor: This section is to be removed before publication]
-00 version:
o -05 - fixed odd spacing in 8.1
o -04 - corrections and tweaks by Jason
o -03 - corrections and clarifications from Nirmal and BVL
o -02 - updated BVL's contact info, clearing one open issue. Also
added content to Security Considerations.
o -01 - updated doc to reflect that this system is deployed and not
in development, closing out two open issues. Added reference for
JavaScript, closing an open issue.
o -00 - first version published
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Authors' Addresses
Chae Chung
Comcast Cable Communications
One Comcast Center
1701 John F. Kennedy Boulevard
Philadelphia, PA 19103
US
Email: chae_chung@cable.comcast.com
URI: http://www.comcast.com
Alex Kasyanov
Comcast Cable Communications
One Comcast Center
1701 John F. Kennedy Boulevard
Philadelphia, PA 19103
US
Email: alexander_kasyanov@cable.comcast.com
URI: http://www.comcast.com
Jason Livingood
Comcast Cable Communications
One Comcast Center
1701 John F. Kennedy Boulevard
Philadelphia, PA 19103
US
Email: jason_livingood@cable.comcast.com
URI: http://www.comcast.com
Nirmal Mody
Comcast Cable Communications
One Comcast Center
1701 John F. Kennedy Boulevard
Philadelphia, PA 19103
US
Email: nirmal_mody@cable.comcast.com
URI: http://www.comcast.com
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Brian Van Lieu
Unaffiliated
Bethlehem, PA 18018
US
Email: brian@vanlieu.net
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