Internet Engineering Task Force S. Perreault, Ed.
Internet-Draft Viagenie
Intended status: BCP I. Yamagata
Expires: February 19, 2012 S. Miyakawa
NTT Communications
A. Nakagawa
Japan Internet Exchange (JPIX)
H. Ashida
IS Consulting G.K.
August 18, 2011
Common requirements for Carrier Grade NAT (CGN)
draft-ietf-behave-lsn-requirements-03
Abstract
This document defines common requirements for Carrier-Grade NAT
(CGN).
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on February 19, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements for CGNs . . . . . . . . . . . . . . . . . . . . 4
4. Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Bulk Port Allocation . . . . . . . . . . . . . . . . . . . . . 10
6. Deployment Considerations . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
10.1. Normative References . . . . . . . . . . . . . . . . . . 12
10.2. Informative Reference . . . . . . . . . . . . . . . . . . 13
Appendix A. Change Log (to be removed by RFC Editor prior to
publication) . . . . . . . . . . . . . . . . . . . . 14
A.1. Changed in -03 . . . . . . . . . . . . . . . . . . . . . 14
A.2. Changed in -02 . . . . . . . . . . . . . . . . . . . . . 15
A.3. Changed in -01 . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
With the shortage of IPv4 addresses, it is expected that more ISPs
may want to provide a service where a public IPv4 address would be
shared by many subscribers. Each subscriber is assigned a private
address, and a NAT situated in the ISP's network translates between
private and public addresses. This is known as NAT444
[I-D.shirasaki-nat444-isp-shared-addr] when the CPE includes a NAT
function.
This is not to be considered a solution to the shortage of IPv4
addresses. It is a service that can conceivably be offered alongside
others, such as IPv6 services or regular, un-NATed IPv4 service.
Some ISPs started offering such a service long before there was a
shortage of IPv4 addresses, showing that there are driving forces
other than the shortage of IPv4 addresses.
This document describes behavioral requirements that are to be
expected of those ISP-controlled NAT. Meeting this set of
requirements will greatly increase the likelihood that subscribers'
applications will function properly.
Readers should be aware of potential issues that may arise when
sharing a public address between many subscribers. See
[I-D.ford-shared-addressing-issues] for details.
This document builds upon previous works describing requirements for
generic NATs [RFC4787][RFC5382][RFC5508]. These documents still
apply in this context. What follows are additional requirements, to
be satisfied on top of previous ones.
2. Terminology
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 [RFC2119].
Readers are expected to be familiar with [RFC4787] and the terms
defined there. The following additional term is used in this
document:
Carrier-Grade NAT (CGN): A NAT-based [RFC2663] functional element
operated by an administrative entity (e.g. operator) to share the
same address among several subscribers. A CGN is managed by the
administrative entity, not the subscribers.
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Note that the term "carrier-grade" has nothing to do with the
quality of the NAT; that is left to discretion of implementers.
Rather, it is to be understood as a topological qualifier: the
NAT is placed in an ISP's network and translates the traffic of
potentially many subscribers. Subscribers have limited or no
control over the CGN, whereas they typically have full control
over a NAT placed on their premises.
Figure 1 summarizes a common network topology in which a CGN
operates.
.
:
| Internet
............... | ...................
| ISP network
|
|
++------++ External realm
........... | CGN |...............
++------++ Internal realm
| |
| |
| | ISP network
............. | .. | ................
| | Customer premises
++------++ ++------++
| CPE1 | | CPE2 | etc.
++------++ ++------++
Figure 1: CGN network topology
Another possible topology is one for hotspots, where there is no
customer premise or CPE, but where a CGN serves a bunch of customers
who don't trust each other and hence fairness is an issue. One
important difference with the previous topology is the absence of
NAT444. This, however, has no impact on CGN requirements since they
are driven by fairness and robustness in the service provided to
customers, which applies in both cases.
3. Requirements for CGNs
What follows is a list of requirements for CGNs. They are in
addition to those found in other documents such as [RFC4787],
[RFC5382], and [RFC5508].
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REQ-1: A CGN MUST support at least the following transport
protocols: TCP (MUST support [RFC5382]), UDP (MUST support
[RFC4787]), and ICMP (MUST support [RFC5508]). Support for
additional transport protocols is OPTIONAL.
Justification: These protocols are the ones that NATs traditionally
support. The IETF has documented the best current practices for
them.
REQ-2: A CGN MUST have a default "IP address pooling" behavior of
"Paired". The CGN administrator MAY change this behavior on
an application protocol basis.
* When multiple overlapping internal address ranges share
the same external address pool (e.g. DS-Lite
[I-D.ietf-softwire-dual-stack-lite]), external addresses
are paired with subscribers rather than internal
addresses.
Justification: This stronger form of REQ-2 from [RFC4787] is
justified by the stronger need for not breaking applications that
depend on the external address remaining constant.
Note that this requirement applies regardless of the transport
protocol. In other words, a CGN must use the same external IP
address mapping for all sessions associated with the same internal
IP address, be they TCP, UDP, ICMP, something else, or a mix of
different protocols.
The justification for allowing other behaviors is to allow the
administrator to save external addresses and ports for application
protocols that are known to work fine with other behaviors in
practice. However, the default behavior MUST be "Paired".
REQ-3: A CGN SHOULD limit the number of external ports (or,
equivalently, "identifiers" for ICMP) that are assigned per
subscriber.
A. Limits SHOULD be configurable by the CGN administrator.
B. Limits MAY be configured and applied independently per
transport protocol.
C. Additionally, it is RECOMMENDED that the CGN include
administrator-adjustable thresholds to prevent a single
subscriber from consuming excessive CPU resources from
the CGN (e.g. rate limit the subscriber's creation of new
mappings).
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Justification: A CGN can be considered a network resource that is
shared by competing subscribers. Limiting the number of external
ports assigned to each subscriber mitigates the DoS attack that a
subscriber could launch against other subscribers through the CGN
in order to get a larger share of the resource. It ensures
fairness among subscribers. Limiting the rate of allocation
mitigates a similar attack where the CPU is the resource being
targeted instead of port numbers.
REQ-4: A CGN SHOULD limit the amount of state memory allocated per
mapping and per subscriber. This may include limiting the
number of TCP sessions, the number of filters, etc.,
depending on the NAT implementation.
A. Limits SHOULD be configurable by the CGN administrator.
B. Additionally, it SHOULD be possible to limit the rate at
which memory-consuming state elements are allocated.
Justification: A NAT needs to keep track of TCP sessions associated
to each mapping. This state consumes resources for which, in the
case of a CGN, subscribers may compete. It is necessary to ensure
that each subscriber has access to a fair share of the CGN's
resources. Limiting TCP sessions per subscriber and per time unit
is an effective mitigation against inter-subscriber DoS attacks.
Limiting the rate of allocation is intended to prevent against CPU
resource exhaustion.
REQ-5: It SHOULD be possible to administratively turn off
translation for specific destination addresses and/or ports.
Justification: It is common for a CGN administrator to provide
access for subscribers to servers installed in the ISP's network,
in the external realm. When such a server is able to reach the
internal realm via normal routing (which is entirely controlled by
the ISP), translation is unneeded. In that case, the CGN may
forward packets without modification, thus acting like a plain
router. This may represent an important efficiency gain.
Figure 2 illustrates this use-case.
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X1:x1 X1':x1' X2:x2
+---+from X1:x1 +---+from X1:x1 +---+
| | to X2:x2 | | to X2:x2 | S |
| C |>>>>>>>>>>>>| C |>>>>>>>>>>>>>>| e |
| P | | G | | r |
| E |<<<<<<<<<<<<| N |<<<<<<<<<<<<<<| v |
| |from X2:x2 | |from X2:x2 | e |
| | to X1:x1 | | to X1:x1 | r |
+---+ +---+ +---+
Figure 2: CGN pass-through
REQ-6: It is RECOMMENDED that a CGN have an "Endpoint-Independent
Filtering" behavior.
Justification: This is a stronger form of REQ-8 from [RFC4787]. An
"Address-Dependent Filtering" behavior is NOT RECOMMENDED. This
is based on the observation that some games and peer-to-peer
applications require EIF for the NAT traversal to work. In the
context of a CGN it is important to minimise application breakage.
REQ-7: When a CGN loses state (due to a crash, reboot, failover to a
cold standby, etc.), it MUST NOT reuse the same external
address+port pairs for new dynamic mappings for at least 120
seconds, except for the following cases:
A. If the CGN tracks TCP sessions (e.g. with a state
machine, as in [RFC6146] section 3.5.2.2), TCP ports MAY
be reused immediately.
B. If the allocated external ports used address-dependent or
address-and-port-dependent filtering before state loss,
they MAY be reused immediately.
Justification: This is necessary in order to prevent collisions
between old and new mappings and sessions. It ensures that all
established sessions are broken instead of redirected to a
different peer.
The exceptions are for cases where reusing a port immediately does
not create a possibility that packets would be redirected to the
wrong peer.
The 120 seconds value corresponds to the Maximum Segment Lifetime
(MSL) from [RFC0793].
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One way that this requirement could be satisfied would be have two
distinct address pools: one dormant and one active. When
rebooting, the CGN would swap the dormant pool with the active
pool. Another way would be simply to wait 120 seconds before
resuming NAT activity.
REQ-8: Once an external port is deallocated, it SHOULD NOT be
reallocated to a new mapping until at least 120 seconds have
passed. The length of time and the maximum number of ports
in this state SHOULD be configurable by the CGN
administrator. The following exceptions apply:
A. If the CGN tracks TCP sessions (e.g. with a state
machine, as in [RFC6146] section 3.5.2.2), TCP ports MAY
be reused immediately.
B. If the allocated external ports used address-dependent or
address-and-port-dependent filtering before state loss,
they MAY be reused immediately.
Justification: This is to prevent users from receiving unwanted
traffic. It also helps prevent against clock skew when mappings
are logged.
The exceptions are for cases where reusing a port immediately does
not create a possibility that packets would be redirected to the
wrong peer.
The 120 seconds value corresponds to the Maximum Segment Lifetime
(MSL) from [RFC0793].
REQ-9: A CGN SHOULD include a Port Control Protocol server
[I-D.ietf-pcp-base].
Justification: Allowing subscribers to manipulate the NAT state
table with PCP greatly increases the likelihood that applications
will function properly.
REQ-10: A CGN SHOULD support [RFC4008].
Justification: It is anticipated that CGNs will be primarily
deployed in ISP networks where the need for management is
critical.
Note also that there are efforts within the IETF toward creating a
MIB specifically for CGNs [I-D.jpdionne-behave-cgn-mib].
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REQ-11: When packets pass from one side to the other, the DSCP
values MUST be preserved. If the CGN also includes diffserv
classifier and marker functionality it MAY change the DSCP
values.
Justification: See [RFC2983], in particular section 6.
REQ-12: When a CGN is unable to create a mapping due to resource
constraints or administrative restrictions (i.e. quotas)...
A. it MUST drop the original packet;
B. it SHOULD send an ICMP Destination Unreachable message
with code 3 (Port Unreachable) to the session initiator;
C. it SHOULD send a notification (e.g. SNMP trap) towards
a management system (if configured to do so);
D. and it SHOULD NOT delete existing mappings in order to
"make room" for the new one.
Justification: This is a slightly different form of REQ-8 from
[RFC5508]. Code 3 is preferred to code 13 because it is listed as
a "soft error" in [RFC5461], which is important because we don't
want TCP stacks to abort the connection attempt in this case.
Sending an ICMP error may be rate-limited for security reasons,
which is why requirement B is a SHOULD, not a MUST.
Applications generally handle connection establishment failure
better than established connection failure. This is why dropping
the packet initiating the new connection is to preferred to
deleting existing mappings. See also the rationale in [RFC5508]
section 6.
4. Logging
It may be necessary for CGN administrators to be able to identify a
subscriber based on external IPv4 address, port, and timestamp in
order to deal with abuse and lawful intercept requests. When
multiple subscribers share a single external address, the source
address and port that are visible at the destination host have been
translated from the ones originated by the subscriber.
In order to be able to do this, the CGN would need to log the
following information for each mapping created:
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o subscriber identifier (e.g. internal source address or tunnel
endpoint identifier)
o external source address
o external source port
o destination address (but see below)
o destination port (but see below)
o timestamp
By "subscriber identifier" we mean information that uniquely
identifies a subscriber. For example, in a traditional NAT scenario,
the internal source address would be sufficient. In the case of DS-
Lite, many subscribers share the same internal address and the
subscriber identifier is the tunnel endpoint identifier (i.e. the
B4's IPv6 address).
A disadvantage of logging mappings is that CGNs under heavy usage may
produce large amounts of logs, which may require large storage
volume.
Readers should be aware of logging recommendations for Internet-
facing servers [I-D.ietf-intarea-server-logging-recommendations].
With compliant servers, the destination address and port do not need
to be logged by the CGN. This can help reduce the amount of logging.
5. Bulk Port Allocation
So far we have assumed that a CGN allocates one external port for
every outgoing connection. In this section, the impacts of
allocating multiple external ports at a time are discussed.
There is a range of things a CGN can do:
Traditional: For every outgoing connection, allocate one external
port.
Scattered port set: For an outgoing connection, create a set of
several non-consecutive external ports. Subsequent outgoing
connections will use ports from the set. When the set is
exhausted, a new connection causes a new set to be created. A set
is smaller or equal to the user's maximum port limit.
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Consecutive port set: Same as the scattered port set, but the ports
allocated to a set are consecutive.
Note that this list is not exhaustive. There is a continuum of
behavior that a CGN may choose to implement. For example, a CGN
could use scattered port sets of consecutive port sets.
The impacts of bulk port allocation are as follows.
Port Utilization: The mechanisms at the top of the list are very
efficient in their port utilization. In that sense, they have
good scaling properties (nothing is wasted). The mechanisms at
the bottom of the list will waste ports. The number of wasted
ports is proportional to size of the "bin".
Logging: Traditional allocation creates a lot of log entries as
compared to allocation by port sets create much fewer entries.
Scattered and consecutive port sets generate the same number of
log entries. In the case of consecutive port sets, entries can be
expressed very compactly by indicating a range (e.g. "12000-
12009"). Some scattered port set allocation schemes can also
generate small log entries containing the parameters and algorithm
used for the port set generation (see e.g.
[I-D.boucadair-pppext-portrange-option]).
With large set sizes, the logging frequency for scattered and
consecutive port sets can approach that of DHCP servers.
Logging destination addresses and ports can only be done on a per-
session basis. This means that destination logging for a CGN
implementing bulk port allocation would create one log entry per
session containing the destination address and port. Other
information could still be logged in one entry per port set.
Security: Traditional and scattered port sets provide very good
security in that ports numbers are not easily guessed. Easily
guessed port numbers put subscribers at risk of the attacks
described in [RFC6056]. Consecutive port sets provides poor
security to subscribers, especially if the set size is small.
6. Deployment Considerations
Several issues are encountered when CGNs are used
[I-D.ietf-intarea-shared-addressing-issues]. There is current work
in the IETF toward alleviating some of these issues. For example,
see [I-D.boucadair-intarea-nat-reveal-analysis].
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The address sharing ratio is the ratio between the number of external
addresses and the number of internal addresses that a CGN is
configured to handle. See
[I-D.ietf-intarea-shared-addressing-issues] section 26.2 for guidance
on picking an appropriate ratio.
7. IANA Considerations
There are no IANA considerations.
8. Security Considerations
If a malicious subscriber can spoof another subscriber's CPE, it may
cause a DoS to that subscriber by creating mappings up to the allowed
limit. Therefore, the CGN administrator SHOULD ensure that spoofing
is impossible. This can be accomplished with ingress filtering, as
described in [RFC2827].
9. Acknowledgements
Thanks for the input and review by Arifumi Matsumoto, Benson
Schliesser, Dai Kuwabara, Dan Wing, Dave Thaler, Francis Dupont, Joe
Touch, Lars Eggert, Kousuke Shishikura, Mohamed Boucadair, Nejc
Skoberne, Reinaldo Penno, Senthil Sivakumar, Takanori Mizuguchi,
Takeshi Tomochika, Tomohiro Fujisaki, Tomohiro Nishitani, Tomoya
Yoshida, and Yasuhiro Shirasaki. Dan Wing also contributed much of
section 5.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4008] Rohit, R., Srisuresh, P., Raghunarayan, R., Pai, N., and
C. Wang, "Definitions of Managed Objects for Network
Address Translators (NAT)", RFC 4008, March 2005.
[RFC4787] Audet, F. and C. Jennings, "Network Address Translation
(NAT) Behavioral Requirements for Unicast UDP", BCP 127,
RFC 4787, January 2007.
[RFC5382] Guha, S., Biswas, K., Ford, B., Sivakumar, S., and P.
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Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142,
RFC 5382, October 2008.
[RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT
Behavioral Requirements for ICMP", BCP 148, RFC 5508,
April 2009.
[I-D.ietf-pcp-base]
Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
Selkirk, "Port Control Protocol (PCP)",
draft-ietf-pcp-base-13 (work in progress), July 2011.
10.2. Informative Reference
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations",
RFC 2663, August 1999.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC2983] Black, D., "Differentiated Services and Tunnels",
RFC 2983, October 2000.
[RFC5461] Gont, F., "TCP's Reaction to Soft Errors", RFC 5461,
February 2009.
[RFC6056] Larsen, M. and F. Gont, "Recommendations for Transport-
Protocol Port Randomization", BCP 156, RFC 6056,
January 2011.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, April 2011.
[I-D.ietf-intarea-server-logging-recommendations]
Durand, A., Gashinsky, I., Lee, D., and S. Sheppard,
"Logging recommendations for Internet facing servers",
draft-ietf-intarea-server-logging-recommendations-04 (work
in progress), April 2011.
[I-D.ietf-intarea-shared-addressing-issues]
Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing",
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draft-ietf-intarea-shared-addressing-issues-05 (work in
progress), March 2011.
[I-D.ietf-softwire-dual-stack-lite]
Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", draft-ietf-softwire-dual-stack-lite-11 (work
in progress), May 2011.
[I-D.boucadair-intarea-nat-reveal-analysis]
Boucadair, M., Touch, J., Levis, P., and R. Penno,
"Analysis of Solution Candidates to Reveal a Host
Identifier in Shared Address Deployments",
draft-boucadair-intarea-nat-reveal-analysis-03 (work in
progress), June 2011.
[I-D.boucadair-pppext-portrange-option]
Boucadair, M., Levis, P., Bajko, G., Savolainen, T., and
T. ZOU), "Huawei Port Range Configuration Options for PPP
IPCP", draft-boucadair-pppext-portrange-option-06 (work in
progress), June 2011.
[I-D.ford-shared-addressing-issues]
Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing",
draft-ford-shared-addressing-issues-02 (work in progress),
March 2010.
[I-D.jpdionne-behave-cgn-mib]
Dionne, J. and M. Blanchet, "CGN Management Information
Base (MIB)", draft-jpdionne-behave-cgn-mib-00 (work in
progress), July 2011.
[I-D.shirasaki-nat444-isp-shared-addr]
Shirasaki, Y., Miyakawa, S., Nakagawa, A., Yamaguchi, J.,
and H. Ashida, "NAT444 addressing models",
draft-shirasaki-nat444-isp-shared-addr-05 (work in
progress), January 2011.
Appendix A. Change Log (to be removed by RFC Editor prior to
publication)
A.1. Changed in -03
o Added exceptions for which it is not necessary to wait 120 seconds
before reusing a port.
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o Renamed "random port set" to "scattered port set", which is more
accurate.
o Log "subscriber identifier" instead of internal address+port to
allow for overlapping internal address ranges (DS-Lite).
o Adjusted logging text and added reference to I-D.boucadair-pppext-
portrange-option.
o Adjusted destination logging text for bulk port allocation
schemes.
o Removed requirement for I-D.ietf-intarea-ipv4-id-update.
o Made PCP support a SHOULD-level requirement.
o Lowered the level of requirement for not dropping existing
mappings in order to "make room" to SHOULD level, and added
rationale.
A.2. Changed in -02
o CGNs MUST support at least TCP, UDP, and ICMP.
o Add requirement from I-D.ietf-intarea-ipv4-id-update.
o Add informative reference to
[I-D.ietf-intarea-shared-addressing-issues].
o Add requirement (SHOULD level) for a port forwarding protocol.
o Allow any pooling behavior on a per-application protocol basis.
o Adjust wording for external port allocation rate limiting.
o Add requirement for RFC4008 support (SHOULD level).
o Adjust wording for swapping address pools when rebooting.
o Add DSCP requirement (stolen from draft-jennings-behave-nat6).
o Add informative reference to
draft-boucadair-intarea-nat-reveal-analysis.
o Add requirement for hold-down pool.
o Change definition of CGN.
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o Avoid usage of "device" loaded word throughout the document.
o Add requirement about resource exhaustion.
o Change title.
o Describe additional CGN topology where there is no NAT444.
o Better justification for "Paired" pool behavior.
o Make it clear that rate limiting allocation is for preserving CPU
resources
o Generalize the requirement for limiting the number of TCP sessions
per mapping so that it applies to all memory-consuming state
elements.
o Change CPE to subscriber where it applies throughout the text.
o Better terminology for bulk port allocation mechanisms.
o Explain how external address pairing works with DS-Lite.
A.3. Changed in -01
o Terminology: LSN is now CGN.
o Imported all requirements from RFCs 4787, 5382, and 5508. This
allowed us to eliminate some duplication.
o Added references to
draft-ietf-intarea-server-logging-recommendations and
draft-ford-shared-addressing-issues.
o Incorporated a requirement from
draft-xu-behave-stateful-nat-standby-06.
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Authors' Addresses
Simon Perreault (editor)
Viagenie
2875 boul. Laurier, suite D2-630
Quebec, QC G1V 2M2
Canada
Phone: +1 418 656 9254
Email: simon.perreault@viagenie.ca
URI: http://www.viagenie.ca
Ikuhei Yamagata
NTT Communications Corporation
Gran Park Tower 17F, 3-4-1 Shibaura, Minato-ku
Tokyo 108-8118
Japan
Phone: +81 50 3812 4704
Email: ikuhei@nttv6.jp
Shin Miyakawa
NTT Communications Corporation
Gran Park Tower 17F, 3-4-1 Shibaura, Minato-ku
Tokyo 108-8118
Japan
Phone: +81 50 3812 4695
Email: miyakawa@nttv6.jp
Akira Nakagawa
Japan Internet Exchange Co., Ltd. (JPIX)
Otemachi Building 21F, 1-8-1 Otemachi, Chiyoda-ku
Tokyo 100-0004
Japan
Phone: +81 90 9242 2717
Email: a-nakagawa@jpix.ad.jp
Perreault, et al. Expires February 19, 2012 [Page 17]
Internet-Draft CGN Requirements August 2011
Hiroyuki Ashida
IS Consulting G.K.
12-17 Odenma-cho Nihonbashi Chuo-ku
Tokyo 103-0011
Japan
Email: assie@hir.jp
Perreault, et al. Expires February 19, 2012 [Page 18]
