Network Working Group F. Baker
Internet-Draft Cisco Systems
Expires: March 25, 2005 P. Bose
Lockheed Martin
September 24, 2004
QoS Signaling in a Nested Virtual Private Network
draft-baker-tsvwg-vpn-signaled-preemption-01
Status of this Memo
This document is an Internet-Draft and is subject to all provisions
of section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of
which he or she is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with
RFC 3668.
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 March 25, 2005.
Copyright Notice
Copyright (C) The Internet Society (2004).
Abstract
Some networks require communication between an interior and exterior
portion of a VPN, but have sensitivities about what information is
communicated across the boundary. This note seeks to outline the
issues and the nature of the proposed solutions.
Baker & Bose Expires March 25, 2005 [Page 1]
Internet-Draft QoS in a Nested VPN September 2004
Table of Contents
1. QoS in a nested VPN . . . . . . . . . . . . . . . . . . . . . 3
1.1 Nested VPNs . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Signaled QoS technology . . . . . . . . . . . . . . . . . 7
1.3 The Resource Reservation Protocol (RSVP) . . . . . . . . . 8
1.4 Logical structure of a VPN Router . . . . . . . . . . . . 10
2. Reservation and Preemption in a nested VPN . . . . . . . . . . 12
2.1 Reservation in a nested VPN . . . . . . . . . . . . . . . 12
2.2 Preemption in a nested VPN . . . . . . . . . . . . . . . . 15
2.3 Working through an example . . . . . . . . . . . . . . . . 16
2.3.1 Initial routine reservations - generating network
state . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.2 Initial routine reservations - request reservation . . 18
2.3.3 Installation of a reservation using precedence . . . . 20
2.3.4 Installation of a reservation using preemption . . . . 20
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
4. Security Considerations . . . . . . . . . . . . . . . . . . . 23
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 24
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.1 Normative References . . . . . . . . . . . . . . . . . . . . 24
6.2 Informative References . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 27
Intellectual Property and Copyright Statements . . . . . . . . 28
Baker & Bose Expires March 25, 2005 [Page 2]
Internet-Draft QoS in a Nested VPN September 2004
1. QoS in a nested VPN
More and more networks wish to guarantee secure transmission of IP
traffic for across public LANs or WANs and therefore use Virtual
Private Networks. Some networks require communication between an
interior and exterior portion of a VPN, but have sensitivities about
what information is communicated across the boundary. This note
seeks to outline the issues and the nature of the proposed solutions.
The outline of the QoS solution for real-time traffic has been
described at a high level in [I-D.baker-tsvwg-mlpp-that-works]. The
key characteristics of this proposal are that
o it uses standardized protocols,
o It includes reservation setup and teardown for guaranteed and
controlled load services using the standardized protocols,
o it is independent of link delay, and therefore consistent with
high delay*bandwidth networks as well as the more common variety,
o it has no single point of failure, such as a central reservation
manager,
o It provides for the preemption of established data flows,
o In that preemption, it not only permits a policy-admitted data
flow in, but selects a specific data flow to exclude based upon
control input rather than simply accepting a loss of service
dictated at the discretion of the network control function, and
o interoperates directly with SIP Proxies, H. 323 Gatekeepers, or
other call management subsystems to present the other services
required in a preemptive or preferential telephone network.
The thrust of the memo surrounds VPNs that use encryption in some
form, such as IPSEC. As a result, we will discuss the VPN Router
supporting "plaintext" and "ciphertext" interfaces. However, the
concept extends readily to any form of aggregation, including the
concept proposed in [RFC3175] of the IP traffic entering and leaving
a network at identified points, and the use of other kinds of tunnels
including GRE, IP/IP, MPLS, and so on.
A note on the use of the words "priority" and "precedence" in this
document is in order. The term "priority" has been used in this
context with a variety of meanings, resulting in a great deal of
confusion. The term "priority" is used in this document in the sense
of a strict comparison. A priority scheduler always chooses a higher
priority message in place of a lower priority message, shielding one
Baker & Bose Expires March 25, 2005 [Page 3]
Internet-Draft QoS in a Nested VPN September 2004
class of traffic from jitter by passing jitter it would otherwise
have experienced to another class. When deciding which sessions are
retained and which are preempted, the meaning imported from [RFC3181]
is that a higher priority session is retained and a lower priority
session is shut down. The term "precedence" is used in the sense
implied in the phrase "Multi-Level Precedence and Preemption"
[ITU.MLPP.1990]; some classes of sessions take precedence over
others, which may result in bandwidth being admitted that might not
otherwise have been or may result in the prejudicial termination of a
lower precedence session, under a stated set of circumstances.
"Priority" is a set of algorithms, where "precedence" is a set of
expectations of what the algorithms may result in. The techniques of
priority comparisons are used in a router or a policy decision point
to implement precedence, but they are not the same thing.
Along the same lines, it is important for the reader to understand
the difference between QoS policies and policies based on the
"importance" of data to the person or function using it. Voice,
regardless of the precedence level of the call, is impeded by high
levels of variation in network-induced delay. As a result, voice is
often serviced using a priority queue, transferring jitter from that
application's traffic to other applications. This is as true of
voice for routine calls as it is for flash traffic. Routing
protocols such as OSPF or BGP are critical to the correct functioning
of network infrastructure. While they are designed to work well with
moderate loss levels, they are not helped by them, and even a short
period of high loss can result in dramatic network events. Variation
in delay, however, is not at all an issue if it is within reasonable
bounds. As a result, it is common for routers to treat routing
protocol messages in a way that limits the probability of loss,
accepting relatively high delay in some cases, even though the
traffic is absolutely critical to the network. Telephone call setup
exchanges have this characteristic as well: faced with a choice
between loss and delay, protocols like SIP and H. 323 far prefer the
latter, as the call setup time is far less than it would be if
messages had to be retransmitted, and this is true regardless of
whether the call is routine or of high precedence. As such, QoS
markings tell us how to provide good service to an application
independent of how "important" it may be at the current time, while
"importance" can be conveyed separately in many cases.
1.1 Nested VPNs
One could describe such a network in terms of three network diagrams.
Figure 1 shows a simple network stretched across a VPN connection.
The VPN router (where, following [RFC2460], a "router" is "a node
that forwards packets not explicitly addressed to itself"), performs
the following steps: it
Baker & Bose Expires March 25, 2005 [Page 4]
Internet-Draft QoS in a Nested VPN September 2004
o receives an IP datagram from a plain text interface,
o determines what remote enclave and therefore other VPN router to
forward it to,
o ensures that it has a security association with that router,
o encloses the encrypted datagram within another VPN (e. g. IPSEC)
and IP header, and
o forwards the encapsulated message toward the remote VPN router.
The receiving VPN router reverses the steps: it
o determines what security association the message was received
from,
o decrypts the interior message,
o forwards the now-decapsulated datagram on a plain text interface.
The use of IPSEC in this manner is described as the tunnel mode of
[RFC2401] and [RFC2406].
Host Host Host Host Host Host
/------------------/ /------------------/
Router -------Router
|
VPN-Router
||
|| IPSEC Tunnel through routed network
||
VPN-Router
|
Router -------Router
/------------------/ /------------------/
Host Host Host Host Host Host
Figure 1: VPN-connected enclave
An important point to understand is that the VPN tunnel, like other
features of the routed network, are invisible to the host. The host
can infer that "something out there" is affecting the Path MTU,
introducing delay, or otherwise affecting its data stream, but if
properly implemented it should be able to adapt to these. The words
"if properly implemented" are the bane of every network manager,
however; substandard implementations do demonstrably exist.
Outside of the enclave, the hosts are essentially invisible. The
Baker & Bose Expires March 25, 2005 [Page 5]
Internet-Draft QoS in a Nested VPN September 2004
communicating enclaves look like a simple data exchange between peer
hosts across a routed network, as shown in Figure 2.
VPN-Router
|
Router
|
VPN-Router
Figure 2: VPN-connected enclave from exterior perspective
Such networks can be nested and re-used in a complex manner. As
shown in Figure 3, a pair of enclaves might communicate across a
ciphertext network which, for various reasons, is itself re-encrypted
and transmitted across a larger ciphertext network. The reasons for
doing this vary, but they relate to information-hiding in the wider
network, different levels of security required for different enclosed
enclaves, and so on.
Baker & Bose Expires March 25, 2005 [Page 6]
Internet-Draft QoS in a Nested VPN September 2004
Host Host Host Host Host Host
/------------------/ /------------------/
Router -------Router
|
VPN-Router VPN-Router VPN-Router
/---------------------/ /----------/
Router -------------Router
|
VPN-Router VPN-Router
/-----------/ /----------/
Router -------Router
|
|
Router -------Router
/-----------/ /----------/
VPN-Router VPN-Router
|
Router ------------Router
/---------------------/ /----------/
VPN-Router VPN-Router VPN-Router
|
Router -------Router
/------------------/ /------------------/
Host Host Host Host Host Host
Figure 3: Nested VPN
The key question this document explores is "how do reservations, and
preemption of reservations, work in such an environment?"
1.2 Signaled QoS technology
The Integrated Services model for networking was originally proposed
in [RFC1633]. In short, it divides all applications into two broad
classes: those that will adapt themselves to any available bandwidth,
and those that will not or cannot. In its own words,
One class of applications needs the data in each packet by a
certain time and, if the data has not arrived by then, the data
is essentially worthless; we call these "real-time"
applications. Another class of applications will always wait
for data to arrive; we call these "elastic" applications.
The Integrated Services model defines data flows supporting
applications as either "real-time" or "elastic". It should be noted
that "real-time" traffic is also referred to as "inelastic" traffic,
and that elastic traffic is occasionally referred to as
"non-real-time. "
Baker & Bose Expires March 25, 2005 [Page 7]
Internet-Draft QoS in a Nested VPN September 2004
In this view, the key issue is the so-called "playback point": a
real-time application is considered to have a certain point in time
at which data describing the next sound, picture, or whatever to be
delivered to a display device or forfeit its utility, while an
elastic application has no such boundary. Another way to look at the
difference is that real-time applications have an irreducible lower
bound on their bandwidth requirements. For example, the typical G.
711 payload is delivered in 160 byte samples (plus 40 bytes of IP/
UDP/RTP headers) at 20 millisecond intervals. This will yield 80
KBPS of bandwidth, without silence suppression, and not accounting
for the layer 2 overhead. To operate in real-time, a G. 711 codec
requires the network over which its data will be delivered to support
communications at 80 KBPS at the IP layer with roughly constant end
to end delay and nominal or no loss. If this is not possible (if
there is significant loss or wide variations in delay), voice quality
will suffer. On the other hand, if many megabits of capacity are
available, the G. 711 codec will not increase its bandwidth
requirements either. Although adaptive codecs exist, (e. g. G.
722. 2 or G. 726), the adaptive mechanism can either require
greater or lesser bandwidth and can adapt only within a certain range
of bandwidth requirements beyond which the quality of the data flow
required is not met. Elastic applications, however, will generally
adapt themselves to any network: if the bottleneck provides 9600 bits
per second, a web transfer or electronic mail exchange will happen at
9600 bits per second, and if hundreds of megabits are available, the
TCP (or SCTP) transport will increase their transfer rate in an
attempt to reduce the time required to accomplish the transfer.
For real-time applications, those that require data to be delivered
end to end with at least a certain rate and with delays varying
between stated bounds, the Integrated Services architecture proposes
the use of a signaling protocol that allows the communicating
applications and the network to communicate about the application
requirements and the network's capability to deliver them. Several
such protocols have been developed or are under development, notably
including RSVP and NSIS. The present discussion is limited to RSVP,
although any protocol that delivers a similar set of capabilities
could be considered.
1.3 The Resource Reservation Protocol (RSVP)
RSVP is initially defined in [RFC2205], with a set of message
processing rules defined in [RFC2209] and message details for
Integrated Services[RFC2210]. Conceptually, this protocol specifies
a way to identify data flows from a source application to a
destination application and request specific resources for them. The
source may be a single machine or a set of machines listed explicitly
or implied, whereas the destination may be a single machine or a
Baker & Bose Expires March 25, 2005 [Page 8]
Internet-Draft QoS in a Nested VPN September 2004
multicast group (and therefore all of the machines in it). Each
application is specified by a transport protocol number in the IP
protocol field, or may additionally include destination and perhaps
source port numbers. The protocol is defined for both IPv4 [RFC0791]
and IPv6 [RFC2460]. It was recognized immediately that it was also
necessary to provide a means to perform the same function for various
kinds of tunnels, which implies a relationship between what is inside
and what is outside the tunnel. Definitions were therefore developed
for IPSEC [RFC2207] and for more generic forms of tunnels [RFC2746].
With the later development of the Differentiated Services
Architecture [RFC2475], definitions were added to specify the DSCP
[RFC2474] to be used by a standard RSVP data flow in [RFC2996], and
to use a pair of IP addresses and a DSCP as the identifying
information for a data flow[RFC3175].
In addition, the initial definition of the protocol included a
placeholder for policy information, and for preemption of
reservations. This placeholder was later specified in detail in
[RFC2750], with a view to associating a policy[RFC2872] with an
identity[RFC3182], and thereby enabling the network to provide a
contracted service to an authenticated and authorized user. This was
integrated with the Session Initiation Protocol [RFC3261] in
[RFC3312]. Preemption of a reservation is specified in the context,
in [RFC3181], which in essence specifies that a reservation installed
in the network using an Preemption Priority and retained using a
separate Defending Priority may be removed by the network via an RESV
Error message that removes the entire reservation. This has issues,
however, in that the matter is often not quite so black and white.
If the issue is that an existing reservation for 80 KBPS can no
longer be sustained but a 60 KBPS reservation could, it is possible
that a VoIP sender could change from a G. 711 codec to a G. 729
codec and achieve that. Or, if there are multiple sessions in a
tunnel or other aggregate, one of the calls could be eliminated
leaving capacity for the others. [I-D.polk-rsvp-aggregate-reduction]
seeks to address this issue.
In a similar way, a capability was added to limit the possibility of
control messages being spoofed or otherwise
attacked[RFC2747][RFC3097].
[RFC3175] describes several features that are unusual in RSVP, being
specifically set up to handle aggregates in a service provider
network. It describes three key components:
o The RFC 3175 session object, which identifies not the IP addresses
of the packets that are identified, but the IP addresses of the
ingress and egress devices in the network, and the DSCP that the
traffic will use,
Baker & Bose Expires March 25, 2005 [Page 9]
Internet-Draft QoS in a Nested VPN September 2004
o The function of a reservation "aggregator", which operates in the
ingress router and accepts individual reservations from the
"customer" network which it aggregates into the ISP core in a
tunnel, an MPLS LSP, or as a traffic stream that it known to leave
at the deaggregator,
o The function of a reservation "deaggregator", which operates in
the egress router and breaks the aggregate reservation and data
streams back out into individual data streams that may be passed
to other networks.
In retrospect, the Session Object specified by RFC 3175 is useful but
not intrinsically necessary. If the ISP network uses tunnels, such
as MPLS LSPs, IP/IP or GRE tunnels or enclosing IPSEC Security
Associations, the concepts of an aggregator and a deaggregator work
in the same manner, although the reservation mechanism would be that
of [RFC3473] and [RFC3474], [RFC2207], or [RFC2746].
1.4 Logical structure of a VPN Router
The conceptual structure of a VPN Router is similar to that of any
other router. In its simplest form, it is physically a two or more
port device, similar to that shown in Figure 4, which has one or more
interfaces to the protected enclave(s) and one or more interfaces to
the outside world. On the latter, it structures some number of
tunnels (in the case of an IPSEC tunnel, having security
associations) that it can treat as point to point interfaces from a
routing perspective.
Baker & Bose Expires March 25, 2005 [Page 10]
Internet-Draft QoS in a Nested VPN September 2004
+---------+ +-------+ +---------+
| RSVP | |Routing| |IPSEC Mgr|
+----+----+ +---+---+ +----+----+
| | |
+----+-----------+------------------------------+----+
| IP |
+-----------+--------------------+------------+------+
| | |
| +-----+-----+ +----+------+
| | Encrypt/ | | Encrypt/ |
| |Decrypt for| |Decrypt for|
| | Security | | Security |
| |Association| |Association|
| +-----+-----+ +----+------+
| | |
+-----------+------------+ +-----+------------+------+
| Plaintext | | Ciphertext |
| Interface | | Interface |
+------------------------+ +-------------------------+
Figure 4: Logical structure of a VPN Router
In some environments, VPN Routers are used that are constructed of
two half-routers with a private interface between them. This is show
in Figure 5. In such a design, one half-router is entirely within
the enclave and one half-router is entirely within the VPN domain.
They maintain separate routing tables for their various parts of the
network: the enclave half-router knows of other enclave half-routers
and the prefixes they offer, and the public half-router knows of
other public half-routers. There is a private interface between them
on which a very few messages are permitted to pass; these include
o IP datagrams,
o RSVP signaling between the half-routers,
o Control information coordinating security associations, and
o precious little else.
Baker & Bose Expires March 25, 2005 [Page 11]
Internet-Draft QoS in a Nested VPN September 2004
___________________________ _____________________________
| +-+| |+-+ |
| |P|| ||P| |
| |r|| ||r| |
| |i|| ||i| |
| |v|| ||v| +-----+ |
| |a|| ||a| |IPSEC| |
| |t|| ||t| | Mgr | |
|+-------+ |e|| ||e| +-----+ +-------+|
||Enclave| +----+ | || || | +----+ | VPN ||
||Routing| |RSVP+------+I+----+I+-----+RSVP| |Routing||
|+---+---+ +-+--+ |n|| ||n| +--+-+ +---+---+|
| | | +---+ |t|| ||t| | | |
|+---+-------+-+-+Nbr+-+e+----+e+-----+--+----------+---+|
|| IP | +---+ |r|| ||r| | IP ||
||Forwarding | +---+ |f|| ||f| |Forwarding ||
|+---+---------+-+Nbr+-+a+----+a+-----+-+-------+-------+|
| | +---+ |c|| ||c| | | |
| | |e|| ||e|-------+--++---+-------+|
| | +-+| |+-+ Tunnel/ || Tunnel/ ||
| | | | | Security || Security ||
| | | | |Association||Association||
| | | | +-----+-----++-----+-----+|
| | | | | | |
|+---+-------------------+| | +-----+------------+-----+|
||Plaintext || | |Ciphertext ||
||Interface || | |Interface ||
|+-----------------------+| | +------------------------+|
|.........................' `.........................../
Figure 5: VPN Router shown as two half-routers
2. Reservation and Preemption in a nested VPN
Let us discuss how a resource reservation protocol, and specifically
RSVP, might be used in a nested virtual private network.
2.1 Reservation in a nested VPN
A reservation in a nest VPN is very much like a reservation in any
other network, with one exception: it is composed of multiple
reservations that must be coordinated. These include a reservation
within the originating and receiving enclaves and a reservation at
each layer of the VPN, as shown in Figure 6.
Baker & Bose Expires March 25, 2005 [Page 12]
Internet-Draft QoS in a Nested VPN September 2004
/ \
( +--+ +--+ enclave ) ,---------.
.----------. \ |H2+---+R2| / ,-' `
+--+ +--+`--.\ +--+ ++-+ / / +--+ +--+
|H1+---+R1| \`. | ,' / |R3+---+H3|
+--+ +-++ ) '--. +----++ _.-' ( ++-+ +--+
| / _.`---|VPN2||''-. \ |
enclave +----+-i.--'' +----++ `----.\ +----+ enclave
--------|VPN1|' | ``|VPN3| ,
,+----+ | +----+------'
,' --+-------+----------+------------------+---`.
,' ++-+ `.
,' |R7+--------+ `.
/ interface +--+ | \
domain 1 +-+--+ \
_.--------|VPN7|--------.
,-----'' +--+-+ `------. .
`-. ,-' | `-. .-'
`-: inner domain +-++ `.'
( |R9| )
.'. ++-+ ;-.
.' `-. | ,-' `-.
' `------. +-+--+ _.-----' `
interface `---------|VPN8|-------''
domain 2 +-+--+ /
\ | +--+ /
`. +----------+R8| ,'
`. ++-+ ,'
`. --+------------------+-----------+------+-- ,'
,-----+----+ | +----+------.
,' |VPN6|. | _.|VPN4| `
+----+.`----. +----+ _.--'' ,+----+
| \ `--=.-|VPN5|---:' / |
+--+ ++-+ : ,-'' +----+ `--. ; ++-+ +--+
|H6+---+R6| | ,' | `.| |R4+---+H4|
+--+ +--+ ;/ +--+ ++-+ : +--+ +--+
// |H5+---+R5| \
enclave ,'( +--+ +--+ `. enclave
`. ,' \ enclave / '-. ,
`-------' \ / `-------'
Figure 6: Reservations in a nested VPN
Thus, when a host in one enclave opens a reservation to a host in
another enclave, a reservation of the appropriate type and size is
created end to end. As it traverses the VPN Router leaving its
enclave, the reservation information and the data are placed within
the appropriate tunnel (e. g. , the IPSEC Security Association for
Baker & Bose Expires March 25, 2005 [Page 13]
Internet-Draft QoS in a Nested VPN September 2004
its precedence level to the appropriate remote VPN Router). At the
remote VPN Router, it is extracted from the tunnel and passed on its
way to the target system. The data in the enclave will be marked
with a DSCP appropriate to its application and (if there is a
difference) precedence level, and the signaling messages (PATH and
RESV) are marked with a DCLASS object indicating that value. RSVP
signaling messages (PATH and RESV) are marked with a DCLASS object
indicating the value used fo the corresponding data. The DSCP on the
signaling messages, however, is a DSCP for signaling, and has the one
proviso that if routing varies by DSCP then it must be a DSCP that is
routed the same way as the relevant data. The[RFC2872] policy object
specifies the applicable policy (e. g. , "routine service for voice
traffic") and asserts a [RFC3182] credential indicating its user
(which may be a person or a class of persons). As specified in
[RFC3181], it also specifies its Preemption Priority and its
Defending Priority; these enable the Preemption Priority of a new
session to be compared with the Defending Priority of previously
admitted sessions.
On the ciphertext side of the VPN Router, no guarantees result unless
the VPN Router likewise sets up a reservation to the peer VPN Router
across the ciphertext domain. Thus, the VPN Router sets up an
[RFC2207] or [RFC3175] reservation to its peer. In the RFC 2207
case, the same DSCP may be used for all traffic in the class
([RFC3246]'s EF might be used for voice regardless of precedence
level, for example), but the session reservations fit in different
security associations with different policy objects by precedence
level. In the RFC 3175 case, since the DSCP must be used to identify
both the reservation and the corresponding data stream, the aggregate
reservations for different precedence levels require different DSCP
values.
As such, the fundamental necessity is for one VPN Router to act as
what [RFC3175] calls the "aggregator" and another to act as the
"deaggregator", and extend a VPN tunnel between them. If the VPN
Tunnel is an IPSEC Security Association between the VPN routers and
the IP packet is entirely contained within (such as is used to cross
a firewall), then the behavior of [RFC2746] is required of the
tunnel. That bearer will have the following characteristics:
o it will have a DSCP corollary or the same as the DSCP for the data
it carries,
o the reservations and data will be carried in security associations
between the VPN Routers, and
o the specification for the reservation for the tunnel itself will
not be less than the sum of the requirements of the aggregated
Baker & Bose Expires March 25, 2005 [Page 14]
Internet-Draft QoS in a Nested VPN September 2004
reservations.
The following requirements relationships apply between the set of
enclosed reservations and the tunnel reservation:
o The sum of the average rates of the contained reservations, having
been adjusted for the additional IP headers, will be less than or
equal to the average rate of the tunnel reservation.
o The sum of the peak rates of the contained reservations, having
been adjusted for the additional IP headers, will be less than or
equal to the peak rate of the tunnel reservation.
o The sum of the burst sizes of the contained reservations, having
been adjusted for the additional IP headers, will be less than or
equal to the burst size of the tunnel reservation.
o The Preemption Priority of a tunnel reservation is identical to
that of the individual reservations it aggregates.
o The Defending Priority of a tunnel reservation is identical to
that of the individual reservations it aggregates.
This would differ only in the case that measurement-based admission
is in use in the tunnel but not in the end system. In that case, the
tunnel's average bandwidth specification would be greater than or
equal to the actual average offered traffic. Such systems are beyond
the scope of this specification.
As a policy matter, it may be useful to note a quirk in the way
Internet QoS works. If the policies for various precedence levels
specify different thresholds (e. g. , "to accept a new routine
call, the total reserved bandwidth after admission may not exceed X;
to accept a higher precedence level call, the total reserved
bandwidth after admission may not exceed X+Y, and this may be
achieved by preempting a lower precedence level call"), the bandwidth
Y effectively comes from the bandwidth in use by elastic traffic
rather than forcing a preemption event.
2.2 Preemption in a nested VPN
As discussed in Section 1.3, preemption is specified in [RFC3181],
and further addressed in [I-D.polk-rsvp-aggregate-reduction]. The
issue is that in many cases the need is to reduce the bandwidth of a
reservation due to a change in the network, not simply to remove the
reservation. In the case of an end system originated reservation,
the end system might be able to accommodate the need through a change
of codec; in the case of an aggregate of some kind, it could reduce
Baker & Bose Expires March 25, 2005 [Page 15]
Internet-Draft QoS in a Nested VPN September 2004
the bandwidth it is sending by dropping one or more reservations
entirely.
In a nested VPN or other kind of aggregated reservation, this means
that the deaggregator (the VPN Router initiating the RESV message for
the tunnel) must
o receive the RESV Error signaling it to reduce its bandwidth,
o re-issue its RESV accordingly,
o identify one or more of its aggregated reservations, enough to do
the job, and
o signal them to reduce their bandwidth accordingly.
It is possible, of course, that it is signaling them to reduce their
bandwidth to zero, which is functionally equivalent to removing the
reservation as described in [RFC3181].
In the routers in the core, an additional case arises. One could
imagine that some enclave presents the VPN with a single session, and
that session has a higher precedence level. If some interior link is
congested (e. g. , the reserved bandwidth will exceed policy if the
call is admitted), a session between a different pair of VPN Routers
must be preempted. More generally, in selecting a reservation to
preempt, the core router must always select a reservation at the
lowest available Defending Priority. This is the reason that various
precedence levels must be kept separate in the core.
2.3 Working through an example
The network in Figure 6 shows three security layers: six plaintext
enclaves around the periphery, two ciphertext domains connecting them
at one layer (referred to in the diagram as an "interface domain"),
and a third ciphertext domain connecting the first two (referred to
in the diagram as an "inner domain"). The following distribution of
information exists:
o Each enclave has access to general routing information concerning
other enclaves it is authorized to communicate with: systems in it
can translate a DNS name for a remote host or domain and obtain
the corresponding address or prefix.
o Each enclave router also has specific routing information
regarding its own enclave.
o A default route is distributed within the enclave, pointing to its
Baker & Bose Expires March 25, 2005 [Page 16]
Internet-Draft QoS in a Nested VPN September 2004
VPN Router.
o VPN Routers 1-6 are able to translate remote enclave prefixes to
the appropriate remote enclave's VPN Router addresses.
o Each interface domain has access to general routing information
concerning the other interface domains, but not the enclaves.
Systems in an interface domain can translate a DNS name for a
remote interface domain and obtain the corresponding address or
prefix.
o Each interface domain router also has specific routing information
regarding its own interface domain.
o A default route is distributed within the interface domain,
pointing to the "inner" VPN Router.
o VPN Routers 7 and 8 are able to translate remote interface domain
prefixes to remote VPN Router addresses.
o Routers in the inner domain have routing information for that
domain only.
While the example shows three levels, there is nothing magic about
the number three. The model can be extended to any number of
concentric layers.
Note that this example places unidirectional reservations in the
forward direction. In voice and video applications, one generally
has a reservation in each direction. The reverse direction is not
discussed, for the sake of clarity, but operates in the same way in
the reverse direction and uses the same security associations.
2.3.1 Initial routine reservations - generating network state
Now let us install a set of reservations from H1 to H4, H2 to H5, and
H3 to H6, and for the sake of argument let us presume that these are
at the "routine" precedence. H1, H2, and H3 each initiate an RSVP
PATH message describing their traffic. For the sake of argument, let
us presume that H1's reservation is for an [RFC2205] session, H2's
reservation is for a session encrypted using IPSEC, and therefore
depends on [RFC2207], and H3 (which is a PSTN Gateway) sends an
[RFC3175] reservation comprising a number of distinct sessions.
Since these are going to H4, H5, and H6 respectively, the default
route leads them to VPN1, VPN2, and VPN3 respectively.
The VPN Routers each ensure that they have an appropriate security
association or tunnel open to the indicated remote VPN Router (VPN4,
Baker & Bose Expires March 25, 2005 [Page 17]
Internet-Draft QoS in a Nested VPN September 2004
VPN5, or VPN6). This will be a security association or tunnel for
the indicated application at the indicated precedence level. Having
accomplished that, it will place the PATH message into the security
association and forward it. If such does not already exist,
following [RFC3175]'s aggregation model, it will now open a
reservation (send a PATH message) for the tunnel/SA within the
interface domain; if the reservation does exist, the VPN Router will
increase the bandwidth indicated in the ADSPEC appropriately. In
this example, these tunnel/SA reservations will follow the default
route to VPN7.
VPN7 ensures that it has an appropriate security association or
tunnel open to VPN8. This will be a security association or tunnel
for the indicated application at the indicated precedence level.
Having accomplished that, it will place the PATH message into the
security association and forward it. If such does not already exist,
following [RFC3175]'s aggregation model, it will now open a
reservation (send a PATH message) for the tunnel/SA within the
interface domain; if the reservation does exist, the VPN Router will
increase the bandwidth indicated in the ADSPEC appropriately. In
this example, this tunnel/SA reservation is forwarded to VPN8.
VPN8 acts as an [RFC3175] deaggregator for the inner domain. This
means that it receives the PATH message for the inner domain
reservation and stores state, decrypts the data stream from VPN7,
operates on the RSVP messages as an RSVP-configured router, and
forwards the received IP datagrams (including the updated PATH
messages) into its interface domain. The PATH messages originated by
VPN1, VPN2, and VPN3 are therefore forwarded towards VPN4, VPN5, and
VPN6 according to the routing of the interface domain.
VPN4, VPN5, and VPN6 each act as an [RFC3175] deaggregator for the
interface domain. This means that it receives the PATH message for
the interface domain reservation and stores state, decrypts the data
stream from its peer, operates on the RSVP messages as an
RSVP-configured router, and forwards the received IP datagrams
(including the updated PATH messages) into its enclave. The PATH
messages originated by H1, H2, and H3 are therefore forwarded towards
H4, H5, and H6 according to the routing of the enclave.
H4, H5, and H6 now receive the original PATH messages and deliver
them to their application.
2.3.2 Initial routine reservations - request reservation
The application in H4, H5, and H6 decides to install the indicated
reservations, meaning that they now reply with RESV messages. These
messages actually request the bandwidth reservation. Following the
Baker & Bose Expires March 25, 2005 [Page 18]
Internet-Draft QoS in a Nested VPN September 2004
trail left by the PATH messages, the RESV messages traipse back to
their respective sources. The state left by the PATH messages leads
them to VPN4, VPN5, and VPN6 respectively. If the routers in the
enclaves are configured for RSVP, this will be explicitly via R4, R5,
or R6; if they are not, routing will lead them through those routers.
The various RSVP-configured routers en route in the enclave
(including the VPN Router on the "enclave" side) will verify that
there is sufficient bandwidth on their links and that any other
stated policy is also met. Having accomplished that, each will
update its reservation state and forward the RESV message to the
next. The VPN Routers will also each generate an RESV for the
reservation within the interface domain, attempting to set or
increase the bandwidth of the reservation appropriately.
The various RSVP-configured routers en route in the interface domain
(including VPN8) will verify that there is sufficient bandwidth on
their links and that any other stated policy is also met. Having
accomplished that, each will update its reservation state and forward
the RESV message to the next. VPN8 will also generate an RESV for
the reservation within the inner domain, attempting to set or
increase the bandwidth of the reservation appropriately. This gets
the reservation to the inner deaggregator, VPN8.
The various RSVP-configured routers en route in the inner domain
(including VPN7) will verify that there is sufficient bandwidth on
their links and that any other stated policy is also met. Having
accomplished that, each will update its reservation state and forward
the RESV message to the next. This gets the message to VPN7.
VPN7 acts as an [RFC3175] aggregator for the inner domain. This
means that it receives the RESV message for the inner domain
reservation and stores state, decrypts the data stream from VPN8,
operates on the RSVP messages as an RSVP-configured router, and
forwards the received IP datagrams (including the updated RESV
messages) into its interface domain. The RESV messages originated by
VPN4, VPN5, and VPN6 are therefore forwarded towards VPN1, VPN2, and
VPN3 through the interface domain.
VPN1, VPN2, and VPN3 each act as an [RFC3175] aggregator for the
interface domain. This means that it receives the RESV message for
the interface domain reservation and stores state, decrypts the data
stream from its peer, operates on the RSVP messages as an
RSVP-configured router, and forwards the received IP datagrams
(including the updated RESV messages) into its enclave. The RESV
messages originated by H4, H5, and H6 are therefore forwarded towards
H1, H2, and H3 according to the routing of the enclave.
Baker & Bose Expires March 25, 2005 [Page 19]
Internet-Draft QoS in a Nested VPN September 2004
H1, H2, and H3 now receive the original RESV messages and deliver
them to their application.
2.3.3 Installation of a reservation using precedence
Without going through the details called out in Section 2.3.1 and
Section 2.3.2, if sufficient bandwidth exists to support them,
reservations of other precedence levels or other applications may
also be installed across this network. If the "routine" reservations
already described are for voice, for example, and sufficient
bandwidth is available under the relevant policy, a reservation for
voice at the "priority" precedence level might be installed. Due to
the mechanics of preemption, however, this would not expand the
existing "routine" reservations in the interface and inner domains,
as doing this causes loss of information - how much of the
reservation is now "routine" and how much is "priority"? Rather, this
new reservation will open up a separate set of tunnels or security
associations for traffic of its application class at its precedence
between that aggregator and deaggregator.
As a side note, there is an opportunity here that does not exist in
the PSTN. In the PSTN, all circuits are potentially usable by any
PSTN application under a certain set of rules (H channels, such as
are used by video streams, must be contiguous and ordered). As such,
if a channel is not made available to routine traffic but is made
available to priority traffic, the operator is potentially losing
revenue on the reserved bandwidth and deserves remuneration.
However, in the IP Internet, some bandwidth must be kept for basic
functions such as routing, and in general policies will not permit
100% of the bandwidth on an interface to be allocated to one
application at one precedence. As a result, it may be acceptable to
permit a certain portion (e. g. 50%) to be used by routine voice
and a larger amount (e. g. 60%) to be used by voice at a higher
precedence level. Under such a policy, a higher precedence
reservation for voice might not result in the preemption of a routine
call, but rather impact elastic traffic, and might be accepted at a
time that a new reservation of lower precedence might be denied.
In microwave networks, such as satellite or mobile ad hoc, one could
also imagine network management intervention that could change the
characteristics of the radio signal to increase the bandwidth under
some appropriate policy.
2.3.4 Installation of a reservation using preemption
So we now have a number of reservations across the network described
in Figure 6, including several reservations at "routine" precedence
and one at "priority" precedence. For sake of argument, let us
Baker & Bose Expires March 25, 2005 [Page 20]
Internet-Draft QoS in a Nested VPN September 2004
presume that the link from VPN7 to R9 is now fully utilized - all of
the bandwidth allocated by policy to voice at the routine or priority
level has been reserved. Let us further imagine that a new
"priority" reservation is now placed from H3 to H6.
The process described in Section 2.3.1 is followed, resulting in PATH
state across the network for the new reservation. This is installed
even though it is not possible to install a new reservation on
VPN7-R9, as it does not install any reservation and the network does
not know whether H6 will ultimately require a reservation.
The process described in Section 2.3.2 is also followed. The
application in H6 decides to install the indicated reservation,
meaning that it now replies with an RESV message. Following the
trail left by the PATH message, the RESV message traipses back
towards H3. VPN6 and (if RSVP was configured) R6 verify that there
is sufficient bandwidth on their links and that any other stated
policy is also met. Having accomplished that, each will update its
reservation state and forward the RESV message to the next. VPN6
also generates an RESV for the reservation within the interface
domain, attempting to set or increase the bandwidth of the
reservation appropriately.
VPN6, R8, and VPN8's "interface domain" side now verify that there is
sufficient bandwidth on their links and that any other stated policy
is also met. Having accomplished that, each will update its
reservation state and forward the RESV message to the next. VPN8
will also generate an RESV for the reservation within the inner
domain, attempting to set or increase the bandwidth of the
reservation appropriately. This gets the reservation to the inner
deaggregator, VPN8.
VPN8's "inner domain" side and R9 now verify that there is sufficient
bandwidth on their links and that any other stated policy is also
met. At R9, a problem is detected - there is not sufficient
bandwidth under the relevant policy. In the absence of precedence,
R9 would now return an RESV Error indicating that the reservation
could not be increased or installed. In such a case, if a
pre-existing reservation of lower bandwidth already existed, the
previous reservation would remain in place but the new bandwidth
would not be granted, and the originator (H6) would be informed. Let
us clarify what it means to be at a stated precedence: it means that
the POLICY_DATA object in the RESV contains a Preemption Priority and
a Defending Priority with values specified in some memo. With
precedence, [I-D.polk-rsvp-aggregate-reduction]'s algorithm would
have the Preemption Priority of the new reservation compared to the
Defending Priority of extant reservations in the router, of which
there are two: one VPN7->VPN8 at "routine" precedence and one
Baker & Bose Expires March 25, 2005 [Page 21]
Internet-Draft QoS in a Nested VPN September 2004
VPN7->VPN8 at "priority" precedence. Since the Defending Priority of
routine reservation is less than the Preemption Priority of a
"priority" reservation, the "routine" reservation is selected. R9
determines that it will accept the increase in its "priority"
reservation VPN7->VPN8 and reduce the corresponding "routine"
reservation. Two processes now occur in parallel:
o The routine reservation is reduced following the algorithms in
[I-D.polk-rsvp-aggregate-reduction], and
o The priority reservation continues according to the usual rules.
R9 reduces its "routine" reservation by sending an RESV Error
updating its internal state to reflect the reduced reservation and
sending an RESV Error to VPN8 requesting that it reduce its
reservation to a number less than or equal to the relevant threshold
less the sum of the competing reservations. VPN8, acting as a
de-aggregator, makes two changes. On the "inner domain" side, it
marks its reservation down to the indicated rate (the most it is now
permitted to reserve), so that if an RESV Refresh event happens it
will request the specified rate. On the "interface domain" side it
selects one or more of the relevant reservations by an algorithm of
its choosing and requests that it likewise reduce its rate. For sake
of argument, let us imagine that the selected reservation is the one
to VPN5. The RESV Error now makes its way through R8 to VPN5, which
similarly reduces its bandwidth request to the stated amount and
passes a RESV Error message on the "enclave" side requesting that the
reservation be appropriately reduced.
H5 is now faced with a decision. If the request is to reduce its
reservation to zero, that is equivalent to tearing down the
reservation. In this simple case, it sends an RESV Tear to tear down
the reservation entirely and advises its application to adjust its
expectations of the session accordingly, which may mean shutting down
the session. If the request is to reduce it below a certain value,
however, it may be possible for the application to do so and remain
viable. For example, if a VoIP application using a G. 711 codec (80
KBPS) is asked to reduce its bandwidth below 70 KBPS, it may be
possible to renegotiate the codec in use to G. 729 or some other
codec. In such a case, the originating application should re-reserve
at the stated bandwidth (in this case, 70 KBPS), initiate the
application level change, and let the application change the
reservation again (perhaps to 60 KBPS) when it has completed that
process.
For the "priority" reservation, at the same time, R9 believes that it
has sufficient bandwidth and that any other stated policy is also
met, it forwards the RESV to VPN7. Each will update its reservation
Baker & Bose Expires March 25, 2005 [Page 22]
Internet-Draft QoS in a Nested VPN September 2004
state and forward the RESV message to the next. VPN7 now acts as an
[RFC3175] aggregator for the inner domain. This means that it
receives the RESV message for the inner domain reservation and stores
state, decrypts the data stream from VPN8, operates on the RSVP
messages as an RSVP-configured router, and forwards the received IP
datagrams (including the updated RESV messages) into its interface
domain. The RESV messages originated by VPN4, VPN5, and VPN6 are
therefore forwarded towards VPN1, VPN2, and VPN3 through the
interface domain.
VPN3 now acts as an [RFC3175] aggregator for the interface domain.
This means that it receives the RESV message for the interface domain
reservation and stores state, decrypts the data stream from its peer,
operates on the RSVP messages as an RSVP-configured router, and
forwards the received IP datagrams (including the updated RESV
messages) into its enclave. The RESV message originated by H6 is
therefore forwarded towards H3 according to the routing of the
enclave.
H3 now receives the original RESV messages and deliver it to the
relevant application.
3. IANA Considerations
This document makes no request of the IANA.
Note to RFC Editor: in the process assigning numbers and building
IANA registries prior to publication, this section will have served
its purpose. It may therefore be removed upon publication as an RFC.
4. Security Considerations
The typical security concerns of message integrity, node and user
authentication are implicitly met by the security association that
exists between the VPN routers. The secure data stream which flows
between the VPN routers is also used for the reservation signaling
messages flowing between VPN routers. Information that is contained
in these signaling messages receives the same level of encryption
that is received by the data streams.
One of the reasons cited for the nesting of VPN routes in Section 1.1
are the different levels of security across the nested VPN routers.
If the security level decreases from one VPN router to the next VPN
router in the nested path, the reservation signaling messages will by
default receive the lower security level treatment. For most cases,
the lower security treatment is acceptable. In certain networks,
however, the reservation signaling across the entire nested path must
receive the highest security level treatment (e. g. encryption,
Baker & Bose Expires March 25, 2005 [Page 23]
Internet-Draft QoS in a Nested VPN September 2004
authentication of signaling nodes). For example the highest
precedence level may only be signaled to VPN routers which can
provide the highest security levels. If any VPN router in the nested
path is incapable of providing the highest security level, it cannot
participate in the reservation mechanism.
In the general case, the nested path may contain routers which are
either incapable of participating in VPNs or providing required
security levels. These routers can participate in the reservation
only if the lower security level is acceptable (as configured by
policy) for the signaling of reservation messages.
VPN routers encapsulate encrypted IP packets and pre-pend an extra
header on each packet. These packets, whether used for signaling or
data, should be identifiable, at a minimum by the IP addresses and
DSCP value. The pre-pended header, therefore, should contain at a
minimum the DSCP value corresponding to the signaled reservation in
each packet. This may literally be the same DSCP as is used for the
data (forcing control plane traffic to receive the same QoS treatment
as its data), or a different DSCP that is routed identically
(separating control and data plane traffic QoS but not routing).
5. Acknowledgements
Doug Marquis, James Polk, Mike Tibodeau, Pete Babendreier, Roger
Levesque, and Subha Dhesikan gave early review comments.
6. References
6.1 Normative References
[I-D.baker-tsvwg-mlpp-that-works]
Baker, F., "Implementing MLPP for Voice and Video in the
Internet Protocol Suite",
draft-baker-tsvwg-mlpp-that-works-01 (work in progress),
February 2004.
[I-D.polk-rsvp-aggregate-reduction]
Polk, J., "RSVP Extension for Bandwidth Reduction of an
Aggregate", draft-polk-rsvp-aggregate-reduction-00 (work
in progress), July 2004.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S. and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC2207] Berger, L. and T. O'Malley, "RSVP Extensions for IPSEC
Data Flows", RFC 2207, September 1997.
Baker & Bose Expires March 25, 2005 [Page 24]
Internet-Draft QoS in a Nested VPN September 2004
[RFC2746] Terzis, A., Krawczyk, J., Wroclawski, J. and L. Zhang,
"RSVP Operation Over IP Tunnels", RFC 2746, January 2000.
[RFC2750] Herzog, S., "RSVP Extensions for Policy Control", RFC
2750, January 2000.
[RFC2996] Bernet, Y., "Format of the RSVP DCLASS Object", RFC 2996,
November 2000.
[RFC3175] Baker, F., Iturralde, C., Le Faucheur, F. and B. Davie,
"Aggregation of RSVP for IPv4 and IPv6 Reservations", RFC
3175, September 2001.
6.2 Informative References
[ANSI.MLPP.Spec]
American National Standards Institute, "Telecommunications
- Integrated Services Digital Network (ISDN) - Multi-Level
Precedence and Preemption (MLPP) Service Capability", ANSI
T1.619-1992 (R1999), 1992.
[ANSI.MLPP.Supplement]
American National Standards Institute, "MLPP Service
Domain Cause Value Changes", ANSI ANSI T1.619a-1994
(R1999), 1990.
[ITU.MLPP.1990]
International Telecommunications Union, "Multilevel
Precedence and Preemption Service (MLPP)", ITU-T
Recommendation I.255.3, 1990.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September
1981.
[RFC1633] Braden, B., Clark, D. and S. Shenker, "Integrated Services
in the Internet Architecture: an Overview", RFC 1633, June
1994.
[RFC2209] Braden, B. and L. Zhang, "Resource ReSerVation Protocol
(RSVP) -- Version 1 Message Processing Rules", RFC 2209,
September 1997.
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997.
[RFC2401] Kent, S. and R. Atkinson, "Security Architecture for the
Internet Protocol", RFC 2401, November 1998.
Baker & Bose Expires March 25, 2005 [Page 25]
Internet-Draft QoS in a Nested VPN September 2004
[RFC2406] Kent, S. and R. Atkinson, "IP Encapsulating Security
Payload (ESP)", RFC 2406, November 1998.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 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.
[RFC2747] Baker, F., Lindell, B. and M. Talwar, "RSVP Cryptographic
Authentication", RFC 2747, January 2000.
[RFC2872] Bernet, Y. and R. Pabbati, "Application and Sub
Application Identity Policy Element for Use with RSVP",
RFC 2872, June 2000.
[RFC3097] Braden, R. and L. Zhang, "RSVP Cryptographic
Authentication -- Updated Message Type Value", RFC 3097,
April 2001.
[RFC3181] Herzog, S., "Signaled Preemption Priority Policy Element",
RFC 3181, October 2001.
[RFC3182] Yadav, S., Yavatkar, R., Pabbati, R., Ford, P., Moore, T.,
Herzog, S. and R. Hess, "Identity Representation for
RSVP", RFC 3182, October 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.
[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.
[RFC3312] Camarillo, G., Marshall, W. and J. Rosenberg, "Integration
of Resource Management and Session Initiation Protocol
(SIP)", RFC 3312, October 2002.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Baker & Bose Expires March 25, 2005 [Page 26]
Internet-Draft QoS in a Nested VPN September 2004
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC3474] Lin, Z. and D. Pendarakis, "Documentation of IANA
assignments for Generalized MultiProtocol Label Switching
(GMPLS) Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) Usage and Extensions for
Automatically Switched Optical Network (ASON)", RFC 3474,
March 2003.
Authors' Addresses
Fred Baker
Cisco Systems
1121 Via Del Rey
Santa Barbara, California 93117
USA
Phone: +1-408-526-4257
Fax: +1-413-473-2403
EMail: fred@cisco. com
Pratik Bose
Lockheed Martin
22300 Comsat Drive
Clarksburg, Maryland 20871
USA
Phone: +1-301-428-4215
Fax: +1-301-428-5414
EMail: pratik. bose@lmco. com
Baker & Bose Expires March 25, 2005 [Page 27]
Internet-Draft QoS in a Nested VPN September 2004
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Baker & Bose Expires March 25, 2005 [Page 28]