One document matched: draft-ietf-tsvwg-rsvp-ipsec-00.txt
Generic Aggregate RSVP Reservations February 2006
Internet Draft Francois Le Faucheur
Bruce Davie
Cisco Systems, Inc.
Pratik Bose
Lockheed Martin
Chris Christou
Michael Davenport
Booz Allen Hamilton
draft-ietf-tsvwg-rsvp-ipsec-00.txt
Expires: August 2006 February 2006
Generic Aggregate RSVP Reservations
draft-ietf-tsvwg-rsvp-ipsec-00.txt
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Abstract
[RSVP-AGG] defines aggregate RSVP reservations allowing resources to
be reserved in a Diffserv network for a given DSCP from a given
source to a given destination. [RSVP-AGG] also defines how end-to-end
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Generic Aggregate RSVP Reservations February 2006
RSVP reservations can be aggregated onto such aggregate reservations
when transiting through a Diffserv cloud. There are situations where
multiple such aggregate reservations are needed for the same source
IP address, destination IP address and DSCP. However, this is not
supported by the aggregate reservations defined in [RSVP-AGG]. In
order to support this, the present document defines a more flexible
type of aggregate RSVP reservations, referred to as generic aggregate
reservation. Multiple such generic aggregate reservations can be
established for a given DSCP from a given source IP address to a
given destination IP address. The generic aggregate reservations may
be used to aggregate end-to-end RSVP reservations. This document also
defines the procedures for such aggregation. The generic aggregate
reservations may also be used end-to-end directly by end-systems
attached to a Diffserv network.
Copyright Notice
Copyright (C) The Internet Society (2006).
Specification of Requirements
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].
1. Introduction
[RSVP-AGG] defines RSVP aggregate reservations allowing resources to
be reserved in a Diffserv network for a flow characterized by its 3-
tuple <source IP address, destination IP address, DSCP>.
[RSVP-AGG] also defines the procedures for aggregation of end-to-end
RSVP reservations onto such aggregate reservations when transiting
through a Diffserv cloud. Such aggregation is illustrated in Figure 1.
--------------------------
/ Aggregation \
|----| | Region | |----|
H--| R |\ |-----| |------| /| R |-->H
H--| |\\| | |---| |---| | |//| |-->H
|----| \| | | I | | I | | |/ |----|
| Agg |======================>| Deag |
/| | | | | | | |\
H--------//| | |---| |---| | |\\-------->H
H--------/ |-----| |------| \-------->H
| |
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\ /
--------------------------
H = Host requesting end-to-end RSVP reservations
R = RSVP router
Agg = Aggregator
Deag = Deaggregator
I = Interior Router
--> = E2E RSVP reservation
==> = Aggregate RSVP reservation
Figure 1 : Aggregation of E2E Reservations
over aggregate RSVP Reservations
These aggregate reservations use a SESSION type specified in [RSVP-
AGG] that contains the receiver (or Deaggregator) IP address and the
DSCP of the PHB from which Diffserv resources are to be reserved. For
example, in the case of IPv4, the SESSION object is specified as:
o IP4 SESSION object: Class = SESSION,
C-Type = RSVP-AGGREGATE-IP4
+-------------+-------------+-------------+-------------+
| IPv4 Session Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| /////////// | Flags | ///////// | DSCP |
+-------------+-------------+-------------+-------------+
These aggregate reservations use a SENDER_TEMPLATE and FILTER_SPEC
types specified in [RSVP-AGG] and which contains only the sender (or
Aggregator) IP address. For example, in the case of IPv4, the
SENDER_TEMPLATE is specified as:
o IP4 SENDER_TEMPLATE object: Class = SENDER_TEMPLATE,
C-Type = RSVP-AGGREGATE-IP4
+-------------+-------------+-------------+-------------+
| IPv4 Aggregator Address (4 bytes) |
+-------------+-------------+-------------+-------------+
Thus it is possible to establish, from a given source IP address to a
given destination IP address, separate such aggregate reservations
for different DSCPs. However, from a given source IP address to a
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given IP destination address, only a single [RSVP-AGG] aggregate
reservation can be established for a given DSCP.
Situations have since been identified where multiple such aggregate
reservations are needed for the same source IP address, destination
IP address and DSCP. One example is where E2E reservations using
different preemption priorities (as per [RSVP-PREEMP]) need to be
aggregated through a Diffserv cloud using the same DSCP. Using
multiple aggregate reservations for the same DSCP allows enforcement
of the different preemption priorities within the aggregation region.
In turn this allows much more efficient management of the Diffserv
resources and in period of resource shortage allows to sustain a
larger number of E2E reservations with higher preemption priorities.
For example, [SIG-NESTED] discusses in details how end-to-end RSVP
reservations can be established in a nested VPN environment through
RSVP aggregation. In particular, [SIG-NESTED] describes how multiple
parallel generic aggregate reservations (for the same DSCP), each
with different preemption priorities, can be used to efficiently
support the preemption priorities of end-to-end reservations.
This document addresses this requirement for multiple aggregate
reservations for the same DSCP, by defining a more flexible type of
aggregate RSVP reservations, referred to as generic aggregate
reservations. This is achieved primarily by adding the notions of a
Virtual Destination Port and of an Extended Virtual Destination Port
in the RSVP Session object.
The notion of Virtual Destination Port was introduced in [RSVP-IPSEC]
to address a similar requirement (albeit in a different context) for
identification and demultiplexing of sessions beyond the IP
destination address. This document reuses this notion from [RSVP-
IPSEC] for identification and demultiplexing of generic aggregate
sessions beyond the IP destination address and DSCP. This allows
multiple generic aggregate reservations to be established for a given
DSCP, from a given source IP address to a given destination IP
address.
[RSVP-TE] introduced the concept of an Extended Tunnel ID (in
addition to the tunnel egress address and the Tunnel ID) in the
Session object used to establish MPLS Traffic Engineering tunnels
with RSVP. The Extended Tunnel ID provides a very convenient
mechanism for the tunnel ingress node to narrow the scope of the
session to the ingress-egress pair. The ingress node can achieve this
by using one of its own IP addresses as a globally unique identifier
and including it in the Extended Tunnel ID and therefore within the
Session object. This document reuses this notion of Extended Tunnel
ID from [RSVP-TE], simply renaming it Extended Virtual Destination
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Port, in order to provide a convenient mechanism to narrow the scope
of an generic aggregate session to an Aggregator-Deaggregator pair.
The generic aggregate reservations may be used to aggregate end-to-
end RSVP reservations. This document also defines the procedures for
such aggregation. These procedures are based on those of [RSVP-AGG]
and this document only specifies the differences with those.
The generic aggregate reservations may also be used end-to-end
directly by end-systems attached to a Diffserv network.
1.1. Related RFCs and Internet-Drafts
This document is heavily based on [RSVP-AGG]. It reuses [RSVP-AGG]
wherever applicable and specifies the necessary extensions beyond
[RSVP-AGG].
The mechanisms defined in [BW-REDUC] allow an existing reservation to
be reduced in allocated bandwidth in lieu of tearing that reservation
down. These mechanisms are applicable to the generic aggregate
reservations defined in the present document.
[RSVP-TUNNEL] describes a general approach to running RSVP over
various types of tunnels. One of these types of tunnel, referred to
as a "type 2 tunnel", has some similarity with the generic aggregate
reservations described in this document. The similarity stems from
the fact that a single, aggregate reservation is made for the tunnel
while many individual flows are carried over that tunnel. However,
[RSVP-TUNNEL] does not address the use of Diffserv-based
classification and scheduling in the core of a network (between
tunnel endpoints), but rather relies on a UDP/IP tunnel header for
classification. This is why [RSVP-AGG] required additional objects
and procedures beyond those of [RSVP-TUNNEL]. Like [RSVP-AGG], this
document also assumes the use of Diffserv-based classification and
scheduling in the aggregation region and, thus, requires additional
objects and procedures beyond those of [RSVP-TUNNEL].
As explained in section 1, this document reuses the notion of Virtual
Destination Port from [RSVP-IPSEC] and the notion of Extended Tunnel
ID from [RSVP-TE].
1.2. Organization Of This Document
Section 2 defines the new RSVP objects related to generic aggregate
reservations. Section 3 describes the processing rules for handling
of generic aggregate reservations. Section 4 specifies the procedures
for aggregation of end to end RSVP reservations over generic
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aggregate RSVP reservations. Finally Section 5 provides example usage
of how the generic aggregate reservations may be used.
The IANA Considerations and the Security Considerations are discussed
in Section 6 and 7, respectively.
1.3. Change History
1.3.1.
Changes From draft-lefaucheur-rsvp-ipsec-02 To draft-ietf-tsvwg-
rsvp-ipsec-00
The most significant changes are:
o de-correlate the generic aggregate reservations from IPsec
operations, in line with comments from the Security experts
review. This significantly affects (and simplifies
considerably) the document in many places.
o add the notion of Extended Virtual Destination port (reusing
the notion of Extended Tunnel ID of [RSVP-TE]).
o added recommendations on use of IP addresses by Aggregator and
Deaggregator
1.3.2.
Changes From draft-lefaucheur-rsvp-ipsec-01 To draft-lefaucheur-
rsvp-ipsec-02
The most significant changes are:
o added text in section 4.2 about Aggregator/Deaggregator
responsibilities with respect to mapping of end-to-end
reservations onto aggregate reservations. The text also
clarified that DCLASS object is no longer needed in PathErr
message requesting new Aggregate Reservations
o Moved the text discussing details of the procedures to handle
dynamic update of SPI values from Security Considerations
section into a new section 4.4.
o updates to Security Considerations section to start addressing
some comments from Security experts review.
1.3.3.
Changes From draft-lefaucheur-rsvp-ipsec-00 To draft-lefaucheur-
rsvp-ipsec-01
The most significant change is the broadening of the applicability of
the new type of aggregate reservations beyond use for Aggregate
reservations for IPsec tunnels (to environments where IPsec is not
Le Faucheur, et al. [Page 6]
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used). This affects the document in multiple places including the
following changes:
o document renamed to "Generic Aggregate RSVP Reservations"
o added a subsection in Introduction to discuss a case where
Generic Aggregate RSVP Reservations are needed in non IPsec
environments
o added text about the fact that the Generic Aggregate
Reservations can be used with IP-in-IP and GRE encapsulation
(in addition to with IPsec AH and ESP)
o added example usage under Section 5 for environment where
IPsec is not used
The other significant changes are:
o added a subsection on the changes of the [RSVP-AGG] procedures
under Section 4
o added explanation about allocation of VDstPort values by
Deaggregator, in that same subsection
o added value of Protocol ID in all example generic aggregate
reservations in Section 5
2. Object Definition
This document defines two new objects under the SESSION Class and a
new object under a new AGGREGATION SESSION Class.
It reuses the RSVP-AGGREGATE-IP4 FILTER_SPEC, RSVP-AGGREGATE-IP6
FILTER_SPEC, RSVP-AGGREGATE-IP4 SENDER_TEMPLATE and RSVP-AGGREGATE-
IP6 SENDER_TEMPLATE objects defined in [RSVP-AGG].
2.1. SESSION Class
o GENERIC-AGGREGATE-IPv4 SESSION object:
Class = 1
C-Type = To be allocated by IANA
0 7 8 15 16 23 24 31
+-------------+-------------+-------------+-------------+
| IPv4 DestAddress (4 bytes) |
+-------------+-------------+-------------+--+----------+
| Reserved | Flags | vDstPort |Rd| DSCP |
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+-------------+-------------+-------------+--+----------+
| Extended vDstPort |
+-------------+-------------+-------------+-------------+
0 7 8 15 16 23 24 31
IPv4 DestAddress (IPv4 Destination Address)
IPv4 address of the receiver (or Deaggregator)
Reserved
A 8-bit field. All bits MUST be set to 0 on transmit. This field
MUST be ignored on receipt.
VDstPort (Virtual Destination Port)
An 8-bit identifier used in the SESSION that remains constant
over the life of the generic aggregate reservation.
Rd (Reserved)
A 2-bit field. All bits MUST be set to 0 on transmit. This field
MUST be ignored on receipt.
DSCP (Diffserv Code Point)
A 6-bit field containing the DSCP of the PHB from which Diffserv
resources are to be reserved.
Extended vDstPort (Extended Virtual Destination Port)
A 32-bit identifier used in the SESSION that remains constant
over the life of the generic aggregate reservation. Normally set
to all zeros. A sender (or Aggregator) that wishes to narrow the
scope of a SESSION to the sender-receiver pair (or Aggregator-
Deaggregator pair) may place its IPv4 address here as a globally
unique identifier.
o GENERIC-AGGREGATE-IPv6 SESSION object:
Class = 1
C-Type = To be allocated by IANA
0 7 8 15 16 23 24 31
+-------------+-------------+-------------+-------------+
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| |
+ +
| |
+ IPv6 DestAddress (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+--+----------+
| Reserved | Flags | vDstPort |Rd| DSCP |
+-------------+-------------+-------------+--+----------+
| |
+ +
| Extended vDstPort |
+ +
| (16 bytes) |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 7 8 15 16 25 26 31
IPv6 DestAddress (IPv6 Destination Address)
IPv6 address of the receiver (or Deaggregator)
Reserved
A 8-bit field. All bits MUST be set to 0 on transmit. This field
MUST be ignored on receipt.
VDstPort (Virtual Destination Port)
A 8-bit identifier used in the SESSION that remains constant
over the life of the generic aggregate reservation.
Rd (Reserved)
A 2-bit field. All bits MUST be set to 0 on transmit. This field
MUST be ignored on receipt.
DSCP (Diffserv Code Point)
A 6-bit field containing the DSCP of the PHB from which Diffserv
resources are to be reserved
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Extended vDstPort (Extended Virtual Destination Port)
A 16-byte identifier used in the SESSION that remains constant
over the life of the generic aggregate reservation. Normally set
to all zeros. A sender (or Aggregator) that wishes to narrow the
scope of a SESSION to the sender-receiver pair (or Aggregator-
Deaggregator pair) may place its IPv6 address here as a globally
unique identifier.
2.2. AGGREGATION-SESSION Class
o IPv4-AGGREGATION-SESSION object:
Class = To be allocated by IANA
C-Type = To be allocated by IANA
0 7 8 15 16 23 24 31
+-------------+-------------+-------------+-------------+
| Length (bytes) | Class-Num | C-Type |
+-------------+-------------+-------------+-------------+
| |
// SESSION Object //
| |
+-------------+-------------+-------------+-------------+
o IPv6-AGGREGATION-SESSION object:
Class = To be allocated by IANA (same as for
IPv4-AGGREGATION-SESSION)
C-Type = To be allocated by IANA
0 7 8 15 16 23 24 31
+-------------+-------------+-------------+-------------+
| Length (bytes) | Class-Num | C-Type |
+-------------+-------------+-------------+-------------+
| |
// SESSION Object //
| |
+-------------+-------------+-------------+-------------+
For example, if the AGGREGATION-SESSION object is used to indicate
that the Aggregate Session needed is a GENERIC-AGGREGATE-IPv4 SESSION
then the AGGREGATION-SESSION will be encoded like this:
0 7 8 15 16 23 24 31
+-------------+-------------+-------------+-------------+
| |IPv4-AGGR-SES|IPv4-AGGR-SES|
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| Length (bytes) | Class-Num | C-Type |
+-------------+-------------+-------------+-------------+
| IPv4 DestAddress (4 bytes) |
+-------------+-------------+-------------+--+----------+
| Reserved | Flags | vDstPort | DSCP |
+-------------+-------------+-------------+--+----------+
| Extended vDstPort |
+-------------+-------------+-------------+-------------+
0 7 8 15 16 23 24 31
3. Processing Rules For Handling Generic Aggregate RSVP Reservations
This section presents additions to the Processing Rules presented in
[RSVP-PROCESS]. These additions are required in order to properly
process the GENERIC-AGGREGATE-IPv4 (resp. GENERIC-AGGREGATE-IPv6)
SESSION object and the RSVP-AGGREGATE-IP4 (resp. RSVP-AGGREGATE-IP6)
FILTER_SPEC object. Values for referenced error codes can be found in
[RSVP]. As with the other RSVP documents, values for internally
reported (API) errors are not defined.
When referring to the new GENERIC-AGGREGATE-IPv4 and GENERIC-
AGGREGATE-IPv6 SESSION objects, IP version will not be included and
they will be referred to simply as GENERIC-AGGREGATE SESSION, unless
a specific distinction between IPv4 and IPv6 is being made.
When referring to the [RSVP-AGG] RSVP-AGGREGATE-IP4 and
RSVP-AGGREGATE-IP6 SESSION, FILTER_SPEC and SENDER_TEMPLATE objects,
IP version will not be included and they will be referred to simply
as RSVP-AGGREGATE, unless a specific distinction between IPv4 and
IPv6 is being made.
3.1. Required Changes to Path and Resv Processing
Both RESV and PATH processing will need to be changed to support the
new objects.
The following PATH message processing changes are required:
o When a session is defined using the GENERIC-AGGREGATE SESSION
object, only the [RSVP-AGG] RSVP-AGGREGATE SENDER_TEMPLATE may
be used. When this condition is violated in a PATH message
received by an RSVP end-station, the RSVP end-station SHOULD
report a "Conflicting C-Type" API error to the application.
When this condition is violated in a PATH message received by
an RSVP router, the RSVP router MUST consider this as a
message formatting error.
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o For PATH messages that contain the GENERIC-AGGREGATE SESSION
object, the VDstPort value, the Extended VDstPort value and
the DSCP value should be recorded (in addition to the
destination/Deaggregator address and source/aggregator
address). These values form part of the recorded state of the
session. The DSCP may need to be passed to traffic control;
however the vDstPort and Extended VDstPort are not passed to
traffic control since they do not appear inside the data
packets of the corresponding reservation.
The changes to RESV message processing are:
o When a RESV message contains a [RSVP-AGG] RSVP-AGGREGATE
FILTER_SPEC, the session MUST be defined using either the
RSVP-AGGREGATE SESSION object (as per [RSVP-AGG]) or the
GENERIC-AGGREGATE SESSION object (as per this document). If
this condition is not met, an RSVP router or end-station MUST
consider that there is a message formatting error.
o When the RSVP-AGGREGATE FILTER_SPEC is used and the SESSION
type is GENERIC-AGGREGATE, each node MAY have a data
classifier installed for the flow:
* If the node needs to perform fine-grain classification (for
example to perform fine-grain policing on ingress at a trust
boundary) then the node MUST create a data classifier
described by the 3-tuple <DestAddress, SrcAddress, DSCP>.
Note that if multiple reservations are established with
different Virtual Destination Ports (and/or different
Extended Virtual Destination Ports) but with the same
<DestAddress, SrcAddress, DSCP>, then those cannot be
distinguished by the classifier. If the router is using the
classifier for policing purposes, the router will therefore
police those together and MUST program the policing rate to
the sum of the reserved rate across all the corresponding
reservations.
* If the node only needs to perform Diffserv classification
(for example inside the aggregation domain downstream of the
trust boundary) then the node MUST rely on the Diffserv data
classifier based on the DSCP only.
4. Procedures for Aggregation over Generic Aggregate RSVP Reservations
The procedures for Aggregation of E2E Reservations over Generic
Aggregate RSVP Reservations are the same as the procedures specified
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in [RSVP-AGG] with the exceptions of the procedure changes listed in
this section.
As specified in [RSVP-AGG], the Deaggregator is responsible for
mapping a given E2E reservation on a given aggregate reservation. The
Deaggregator requests establishment of a new aggregate reservation by
sending to the Aggregator an E2E PathErr message with an error code
of NEW-AGGREGATE-NEEDED. In [RSVP-AGG], the Deaggregator conveys the
DSCP of the new requested aggregate reservation by including a DCLASS
Object in the E2E PathErr and encoding the corresponding DSCP inside.
This document modifies and extends this procedure. The Deaggregator
MUST include in the E2E PathErr message an AGGREGATION-SESSION object
which contains the Session to be used for establishment of the
requested generic aggregate reservation. Since the AGGREGATION-
SESSION object contains the DSCP, the DCLASS object need not be
included in the PathErr message.
Note that the Deaggregator can easily ensure that different
Aggregators use different sessions for their Aggregate Path towards a
given Deaggregator. This is because the Deaggregator can easily
select VDstPort and/or Extended VDstPort numbers which are different
for each Aggregator (for example by using the Aggregator address as
the Extended VDstPort) and can communicate those inside the
AGGREGATION-SESSION object. This provides an easy solution to
establish separate reservations from every Aggregator to a given
Deaggregator. Conversely, if reservation sharing were needed across
multiple Aggregators, the Deaggregator could facilitate this by
allocating the same VDstPort and Extended VDstPort to the multiple
Aggregators and thus including the same AGGREGATION-SESSION object in
the E2E PathErr messages sent to these Aggregators. The Aggregators
could then all establish an Aggregate Path with the same Session.
Therefore various sharing scenarios can easily be supported. Policies
followed by the Deaggregator to determine which aggregators need
shared or separate reservations are beyond the scope of this document.
The Deaggregator MAY also include in the E2E PathErr message (with an
error code of NEW-AGGREGATE-NEEDED) additional RSVP objects which are
to be used for establishment of the new needed generic aggregate
reservation. For example, the Deaggregator MAY include in the E2E
PathErr an RSVP Signaled Preemption Priority Policy Element (as
specified in [RSVP-PREEMP].
The [RSVP-AGG] procedures for processing of an E2E PathErr message
with an error code of NEW-AGGREGATE-NEEDED by the Aggregator are
extended correspondingly. On receipt of such a message containing an
AGGREGATION-SESSION object, the Aggregator MUST use the Session
provided in the AGGREGATION-SESSION object to trigger establishment
of a generic aggregate reservation. The Aggregator MUST use the
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DestAddress found in the AGGREGATION-SESSION object as the
destination of the Aggregate Path. When an RSVP Signaled Preemption
Priority Policy Element is contained in the received E2E PathErr
message, the Aggregator MUST include this object in the Aggregate
Path for the corresponding generic aggregate reservation. When other
additional objects are contained in the received E2E PathErr message
and those can be unambiguously interpreted as related to the new
needed generic aggregate reservation (as opposed to related to the
E2E reservation), the Aggregator SHOULD include those in the
Aggregate Path for the corresponding generic aggregate reservation.
The Aggregator MUST use as the Source Address (i.e. as the Aggregator
Address) for the generic aggregate reservation, the address it uses
to identify itself as the PHOP when forwarding the E2E Path messages
corresponding to the E2E PathErr message.
The Deaggregator follows the same procedures as described in [RSVP-
AGG] for establishing, maintaining and clearing the aggregate Resv
state. However, in this document, the Deaggregator MUST use the
generic aggregate reservations and hence use the GENERIC-AGGREGATE
SESSION specified earlier in this document.
This document also modifies the procedures of [RSVP-AGG] related to
exchange of E2E Resv messages between Deaggregator and Aggregator.
The Deaggregator MUST include the new AGGREGATION-SESSION object in
the E2E Resv message, in order to convey to the Aggregator which
aggregate session to map a given E2E reservation onto. Again, since
the AGGREGATION-SESSION object contains the DSCP, the DCLASS object
need not be included in the E2E Resv message. The Aggregator MUST
interpret the AGGREGATION-SESSION object in the E2E Resv as
indicating which generic aggregate reservation session the
corresponding E2E reservation is mapped onto.
[RSVP-AGG] describes how the Aggregator and Deaggregator can
communicate their respective identity to each other. For example the
Aggregator includes one of its IP addresses in the RSVP HOP object in
the E2E Path which is transmitted downstream and received by the
Deaggregator once it traversed the aggregation region. Similarly, the
Deaggregator identifies itself to the Aggregator by including one of
its IP addresses in various fields, including the ERROR SPECIFICATION
of the E2E PathErr message (containing the NEW-AGGREGATE-NEEDED Error
Code), in the AGGREGATION-SESSION object included in the same E2E
PathErr message and in the RSVP HOP object of the E2E Resv message.
However, [RSVP-AGG] does not discuss which IP addresses are to be
selected by the aggregator and Deaggregator for such purposes.
Because these addresses are intended to identify the Aggregator and
Deaggregator and not to identify any specific interface on these
devices, this document RECOMMENDS that the Aggregator and
Deaggregator SHOULD use interface-independent addresses (for example
a loopback address) whenever they communicate their respective
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identity to each other. This ensures that respective identification
of the Aggregator and Deaggregator by any interface state change on
these devices. In turns this results in more stable operations and
considerably reduced RSVP signaling in the aggregation region. For
example, if interface-independent addresses are used by the
Aggregator and the Deaggregator, then a failure of an interface on
these devices may simply result in the rerouting of a given generic
aggregate reservation but will not result in the generic aggregate
reservation having to be torn down and another one established, nor
will it result in a change of mapping of E2E reservations on generic
aggregate reservations (assuming the Aggregator and Deaggregator
still have reachability after the failure and the Aggregator and
Deaggregator are still on the shortest path to the destination).
However, when identifying themselves to real RSVP neighbors (i.e.
neighbors which are not on the other side of the aggregation region),
the Aggregator and Deaggregator SHOULD continue using interface-
dependent addresses as per regular [RSVP] procedures. This applies
for example when the Aggregator identifies itself downstream as a
PHOP for the generic aggregate reservation or identifies itself
upstream as a NHOP for an E2E reservation. This also applies when the
Deaggregator identifies itself downstream as a PHOP for the E2E
reservation or identifies itself upstream as a NHOP for the generic
aggregate reservation. As part of the processing of generic aggregate
reservations, interior routers (i.e. routers within the aggregation
region) SHOULD continue using interface-dependent address as per
regular [RSVP] procedures.
More generally, within the aggregation region (ie between Aggregator
and Deaggregator) the operation of RSVP should be modeled with the
notion that E2E reservations are mapped to aggregate reservations and
are no longer tied to physical interfaces (as was the case with
regular RSVP). However, generic aggregate reservations (within the
aggregation region) as well as E2E reservations outside the
aggregation region, retain the model of regular RVSP and remain tied
to physical interfaces.
5. Example Usage Of Multiple Generic Aggregate Reservations Per DSCP
From a Given Aggregator to a Given Deaggregator
Let us consider the environment depicted in Figure 2 below. RSVP
aggregation is used to support E2E reservations between Cloud-1,
Cloud-2 and Cloud-3.
I----------I I----------I
I Cloud-1 I I Cloud-2 I
I----------I I----------I
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Generic Aggregate RSVP Reservations February 2006
| |
Agg-Deag-1------------ Agg-Deag-2
/ \
/ Aggregation |
| Region |
| |
| ---/
\ /
\Agg-Deag-3---------/
|
I----------I
I Cloud-3 I
I----------I
Figure 2 : Example Usage of
Generic Aggregate IP Reservations
Let us assume that:
o the E2E reservations from Cloud-1 to Cloud-3 have a preemption
of either P1 or P2
o the E2E reservations from Cloud-2 to Cloud-3 have a preemption
of either P1 or P2
o the E2E reservations are only for Voice (which needs to be
treated in the aggregation region using the EF PHB)
o traffic from the E2E reservations is encapsulated in Aggregate
IP reservations from Aggregator to Deaggregator using GRE
tunneling ([GRE]).
Then, the following generic aggregate RSVP reservations may be
established from Agg-Deag-1 to Agg-Deag-3 for aggregation of the end-
to-end RSVP reservations:
A first generic aggregate reservation for aggregation of Voice
reservations from Cloud-1 to Cloud-3 requiring use of P1:
* GENERIC-AGGREGATE-IPv4 SESSION=
IPv4 DestAddress= Agg-Deag-3
vDstPort=V1
DSCP=EF
Extended VDstPort= Agg-Deag-1
* STYLE=FF or SE
* IPv4/GPI FILTER_SPEC=
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Generic Aggregate RSVP Reservations February 2006
IPv4 SrcAddress= Agg-Deag-1
* POLICY_DATA (PREEMPTION_PRI)=P1
A second generic aggregate reservation for aggregation of Voice
reservations from Cloud-1 to Cloud-3 requiring use of P2:
* GENERIC-AGGREGATE-IPv4 SESSION=Agg-Deag-3/V2/EF
IPv4 DestAddress= Agg-Deag-3
vDstPort=V2
DSCP=EF
Extended VDstPort= Agg-Deag-1
* STYLE=FF or SE
* IPv4/GPI FILTER_SPEC
IPv4 SrcAddress= Agg-Deag-1
* POLICY_DATA (PREEMPTION_PRI)=P2
where V1 and V2 are arbitrary VDstPort values picked by Agg-Deag-3.
The following generic aggregate RSVP reservations may be established
from Agg-Deag-2 to Agg-Deag-3 for aggregation of the end-to-end RSVP
reservations:
A third generic aggregate reservation for aggregation of Voice
reservations from Cloud-2 to Cloud-3 requiring use of P1:
* GENERIC-AGGREGATE-IPv4 SESSION
IPv4 DestAddress= Agg-Deag-3
vDstPort=V3
DSCP=EF
Extended VDstPort= Agg-Deag-2
* STYLE=FF or SE
* IPv4/GPI FILTER_SPEC
IPv4 SrcAddress= Agg-Deag-2
* POLICY_DATA (PREEMPTION_PRI)=P1
A fourth generic aggregate reservation for aggregation of Voice
reservations from Cloud-2 to Cloud-3 requiring use of P2:
* GENERIC-AGGREGATE-IPv4 SESSION
IPv4 DestAddress= Agg-Deag-3
vDstPort=V4
DSCP=EF
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Generic Aggregate RSVP Reservations February 2006
Extended VDstPort= Agg-Deag-2
* STYLE=FF or SE
* IPv4/GPI FILTER_SPEC=Agg-Deag-2
IPv4 SrcAddress= Agg-Deag-2
* POLICY_DATA (PREEMPTION_PRI)=P2
where V1 and V4 are arbitrary VDstPort values picked by Agg-Deag-3.
Note that V3 and V4 could be equal to V1 and V2 since, in this
example, the Extended VDstPort of the GENERIC-AGGREGATE Session
contains the address of the Deaggregator and, thus, ensures that
different sessions are used for each Deaggregator.
6. Security Considerations
The security considerations associated with the RSVP protocol [RSVP]
apply to this document as it relies on RSVP.
When generic aggregate reservations are used for aggregation of E2E
reservations, the security considerations discussed in [RSVP-AGG]
apply.
The security considerations discussed in [SIG-NESTED] apply when the
generic aggregate reservations are used in the presence of IPsec
gateways.
7. IANA Considerations
This document requests that IANA allocates two new C-Types under the
Class 1 for the two new RSVP objects (GENERIC-AGGREGATE-IPv4 SESSION
and GENERIC-AGGREGATE-IPv6 SESSION) defined in section 2.1.
This document also requests that IANA allocates one new Class-Num and
two new C-Types for the two new RSVP objects (IPv4-AGGREGATION-
SESSION and IPv6-AGGREGATION-SESSION) defined in section 2.2.
8. Acknowledgments
This document borrows heavily from [RSVP-AGG]. It also borrows the
concepts of Virtual Destination Port and Extended Virtual Destination
Port respectively from [RSVP-IPSEC] and [RSVP-TE].
Also, we thank Fred Baker, Roger Levesque, Carol Iturralde, Daniel
Le Faucheur, et al. [Page 18]
Generic Aggregate RSVP Reservations February 2006
Voce and Anil Agarwal for their input into the content of this
document. Thanks to Steve Kent for insightful comments on usage of
RSVP reservations in IPsec environments.
9. Normative References
[RSVP] "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional
Specification", Braden et al, RFC2205
[RSVP-IPSEC] "RSVP Extensions for IPsec Data Flows", Berger et al,
RFC2207
[RSVP-AGG] "Aggregation of RSVP for IPv4 and IPv6 Reservations",
Baker et al, RFC3175
[SIG-NESTED] "QoS Signaling in a Nested Virtual Private Network",
Baker et al, draft-ietf-tsvwg-vpn-signaled-preemption-00.txt, work in
progress
[RSVP-PROCESS] "Resource ReSerVation Protocol (RSVP) -- Version 1
Message Processing Rules", Braden et al, RFC2209
[IPSEC-ARCH] "Security Architecture for the Internet Protocol", Kent
et al, RFC2401
[DS-TUNNEL] "Differentiated Services and Tunnels", Black, RFC2983
[GRE] Generic Routing Encapsulation (GRE). Farinacci et al, RFC 2784
10. Informative References
[BW-REDUC] "A Resource Reservation Extension for the Reduction of
andwidth of a Reservation Flow", Polk et al, draft-polk-tsvwg-rsvp-
bw-reduction-01.txt, work in progress
[RSVP-TUNNEL] "RSVP Operation Over IP Tunnels", Terzis et al., RFC
2746, January 2000.
[RSVP-PREEMP] Herzog, S., "Signaled Preemption Priority Policy
Element", RFC 3181, October 2001.
[RSVP-TE] Awduche et al, RSVP-TE: Extensions to RSVP for LSP Tunnels,
RFC 3209, December 2001.
11. Authors Address:
Le Faucheur, et al. [Page 19]
Generic Aggregate RSVP Reservations February 2006
Francois Le Faucheur
Cisco Systems, Inc.
Village d'Entreprise Green Side - Batiment T3
400, Avenue de Roumanille
06410 Biot Sophia-Antipolis
France
Email: flefauch@cisco.com
Bruce Davie
Cisco Systems, Inc.
300 Beaver Brook Road
Boxborough, MA 01719
USA
Email: bdavie@cisco.com
Pratik Bose
Lockheed Martin
22300 Comsat Drive Clarksburg, MD 20814
USA
Email: pratik.bose@lmco. com
Christou Christou
Booz Allen Hamilton
8283 Greensboro Drive
McLean, VA 22102
USA
Email: christou_chris@bah.com
Michael Davenport
Booz Allen Hamilton
8283 Greensboro Drive
McLean, VA 22102
USA
Email: davenport_michael@bah.com
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Le Faucheur, et al. [Page 20]
Generic Aggregate RSVP Reservations February 2006
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Le Faucheur, et al. [Page 21]
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