[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]
Versions: (draft-aboulmagd-ipo-ason) 00 01 02
IPO WG O. Aboul-Magd
Internet Draft M. Mayer
Document: draft-ietf-ipo-ason-00.txt D. Benjamin
Category: Informational B. Jamoussi
Expires: January 2002 L. Prattico
S. Shew
Nortel Networks
July, 2001
Automatic Switched Optical Network (ASON) Architecture and Its Related
Protocols
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [1].
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.
1. Abstract
This draft describes an architecture for intelligent optical
networks. This architecture is called the automatic switched optical
networks (ASON). ASON is a client-server architecture with well-
defined interfaces that allows clients to request services from the
optical network (server). ASON architecture and its generic
automatic switched transport networks (ASTN) has been an active
study area both at T1X1 and ITU [2,3].
The protocols that run over ASON interfaces are not specified in
[2,3]. The emerging of IP-based protocols, e.g. generalized MPLS
[4], for the control of the optical layer makes it possible for the
ASON/ASTN architecture to benefit from the protocols design work
that has been progressing at the IETF.
2. Conventions used in this document
Aboul-Magd Expires January 2002 1
Draft-ietf-ipo-ason-00.txt July 2001
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC-2119 [5].
3. Introduction
The existing transport networks provide SONET/SDH and WDM services
whose connections are provisioned via network management protocols.
This process is both slow (weeks to months) relative to the
switching speed and costly to the network providers.
An automatic switched optical network (ASON) is an optical/transport
network that has dynamic connection capability. It encompasses
SONET/SDH, wavelength, and potentially fiber connection services in
both OEO and all-optical networks. There are a number of added
values related to such a capability:
- Traffic engineering of optical channels: Where bandwidth
assignment is based on actual demand patterns.
- Mesh network topologies and restoration: Mesh network topologies
can in general be engineered for better utilization for a given
demand matrix. Ring topologies might not be as efficient due to
the asymmetry of traffic patterns.
- Managed bandwidth to core IP network connectivity: A switched
optical network can provide bandwidth and connectivity to an IP
network in a dynamic manner compared to the relatively static
service available today.
- Introduction of new optical services: The availability of switched
optical networks will facilitate the introduction of new services
at the optical layer. Those services include bandwidth on demand
and optical virtual private networks (OVPN).
This draft describes the ASON architecture. ASON and its generic
ASTN has been a topic of active discussion both at the T1X1 and ITU.
The draft focuses on ASON control plane, its requirements, and
related protocols. The ASON architecture at the ITU is discussed in
two documents. The first document is G.807 (previously known as
G.astn)[3] describes network level, technology independent,
requirements for the control plane of ASTN. The second document is
G.ason [2], and it specifies architecture requirements for ASTN
network as applicable to SDH transport networks and optical
transport networks.
4. ASON/ASTN Architecture: An Overview
ASON/ASTN architecture belongs to client-server models or the
overlay network models as defined in [6]. The salient feature of
this model is the existence of well-recognized boundaries between
client networks and provider domains. Client/provider separation is
Aboul-Magd Expires January 2002 2
Draft-ietf-ipo-ason-00.txt July 2001
a direct recognition of today's networking realities where ownership
of layer 3 and layer 1 equipment belongs to different organizations.
This client/provider domain separation entails the running of
different routing instants at each domain. Thus there is no need to
share topology information between carriers and their clients.
The ASON/ASTN is an architecture that allows for global connectivity
as shown in Figure 1. Figure 1 illustrates user end systems
connecting to a global ASTN/ASON network, which may be comprised of
multiple provider domains. As an overlay model there is no trusted
relationship between provider domains so the instantiated interfaces
are E-NNIs. Within a provider domain, the instantiated interface
between control plane entities is the I-NNI.
+----+ UNI +-----------------+ UNI +----+
|user|--------| |--------|user|
+----+ | global ASTN | +----+
+-----------------+
/ \
/ \
+----------+ +----------+
| ASTN | E-NNI | ASTN |
|provider 1|---------|provider 2|
+----------+ +----------+
/ \
/ \
/ \
+-------------------+
| |
| +--+ I-NNI +---+ |
| | |--------| | |
| +--+ +---+ |
+-------------------+
Figure 1: ASON/ASTN Global Architecture
As applied to optical networks, the ASON network interfaces are
further shown in Figure 2. In this Figure all the components that
can form part of ASON are shown. The architecture shown is intended
to allow switching of optical network connections within the optical
transport network under control of ASON signaling network.
There are three separate planes involved in the network:
- A transport plane (TP)
- A control plane (CP)
- A management plane (MP)
+--------------------------+ +--------------+
| ASON Control Plane | | |
| | | |
UNI | +------+ I-NNI +------+ E-NNI| +------+ | +------+
------>| OCC |-------| OCC |-|----|----| OCC | | NMI| |
Aboul-Magd Expires January 2002 3
Draft-ietf-ipo-ason-00.txt July 2001
| +------+ +------+ | | +------+ |<-->| |
| ^ ^ | | ^ | | |
+-----|--------------|-----+ +------|-------+ | |
| CCI | | | |
+-----|--------------|-----+ +------|-------+ | |
| v v | | v | | |
| +------+ +------+ | | +-----+ |<-->| |
| | OXC | | OXC | | PI | | OXC | | NMI+------+
| | |-------| |-----------| | |
| +------+ +------+ | | +-----+ | Management
| Transport Plane | | | Plane
+--------------------------+ +--------------+
OCC = Optical Network Controller UNI = User Network Interface
CCI = Connection Control Interface OXC = Optical Cross Connect
I-NNI = Internal Node to Node Interface
E-NNI = External Node to Node Interface
NMI = Network Management Interface
PI = Physical Interface
Figure 2: Automatic Switching Optical Network (ASON) Interfaces
The transport plane contains the transport network elements
(switches and links) that carry the entity that is switched, i.e.
optical connections. End-to-end connections are setup within the
transport plane under the control of the ASON control plane (CP).
This draft is concerned with the CP part of the ASON architecture.
Both the TP and MP are out of the scope of this draft.
5. ASON Control Plane: General Requirements
A well-designed control plane architecture should give service
providers better control of their network, while providing faster
and improved accuracy of circuit set-up. The control plane itself
should be reliable, scalable, and efficient. It should also be
sufficiently generic to support different technologies and differing
business needs and different partitions of functions by vendors
(i.e., different packaging of the control plane components). In
summary, the control plane architecture should:
- Be applicable to a variety of transport network technologies
(e.g., SONET/SDH, OTN, PXC). In order to achieve this goal, it is
essential that the architecture isolates technology dependent
aspects from technology independent aspects, and address them
separately.
- Be sufficiently flexible to accommodate a range of different
network scenarios. This goal may be achieved by partitioning the
control plane into distinct components. This, allows vendors and
service providers to decide the location of these components, and
also allows the service provider to decide the security and policy
control of these components.
Aboul-Magd Expires January 2002 4
Draft-ietf-ipo-ason-00.txt July 2001
The control plane shall support either switched connections (SC) of
soft permenant connections (SPC) of basic connection capability in
transport networks. These connection capabilities types are:
- Uni-directional point-to-point connection
- Bi-directional point-to-point connections
- Uni-directional point-to-multipoint connections
The components of the control plane architecture are illustrated in
Figure 3. This Figure illustrates the control plane functions and
their relationships. These entities can be packaged in different
ways, depending upon the required functionality.
+------------------------------------------------+
| |
| +--------+ |
| | PA | |
| +--------+ |
| | |
| | |
| +------+ +------+ +--------+ |
X----| RTU |---------| RT |------| LRM |---X
| +------+ +------+ +--------+ |
| | / | |
| | ----- | |
| +------+ +------+/ +--------+ |
| | PC | | CC |------| CAC | |
| +------+ +------+ +--------+ |
| | |
+-----------------------X------------------------+
PA = Policing Agent RTU = Routing Table Update
RT = Routing Table LRM = Link Resource Manager
CC = Connection Controller CAC = Connection Admission Control
PC = Protocol Controller
X--- External Interface
Figure 3: ASON/ASTN Control Plane Functional Components
Directory service processes may be utilized by the control plane to
provide a mapping/translation of names and association of these
names between layer networks, sub-network domains (e.g., between
provider domains), and user name translations. This process includes
functions such as registration of a user within the ASON network
(including association of a user name to an ASON name space).
5.1 Connection Controller Function (CC)
The role of this function within the control plane is:
- The management and supervision of connection set-ups;
- The management and supervision of connection releases;
Aboul-Magd Expires January 2002 5
Draft-ietf-ipo-ason-00.txt July 2001
- The modification of connection parameters for existing
connections.
In response to a connection request the function must co-ordinate
the interrogation of the route table, requests to the call admission
control function, and updating the status of connection points.
5.2 Route Table Function (RT)
The route table function consists of a list of reachable
destinations and for each destination a recommended egress link. The
role of the route table function is to respond to the request from
the connection controller for the egress link for a particular
destination.
Note that there are likely to be significant differences between I-
NNI and E-NNI RT functions. Further, the reachability may also be a
function of the policy and routing constraints.
5.3 Route Table Update Function (RTU)
Information stored in routing tables may be manually entered and
updated, as in the case of static routing. However, networks may
also automatically generate and maintain route tables and distribute
them throughout the network (at least within a domain). The role of
the route table update function is to:
- Relay the contents of a local route table for a sub-network to all
of its immediate neighbors;
- Receive the route tables from immediate neighboring sub-network
controllers and update local route table to reflect all of the
destinations it can reach via its neighbors.
5.4 Connection Admission Control Function (CAC)
The role of this function is to decide if there is sufficient free
resource on a link to allow a new connection. If there is the call
admission control may allow a connection request to proceed. If it
is not allowed to proceed then the connection admission control
informs the connection controller to either find a new route or,
where none is available, notify the originator of the connection
request that the request has been refused. In principle there is a
connection admission control function associated with every resource
manager.
Connection admission control can also be decided based on
prioritization or on other policy decisions. CAC policies are
outside the scope of standardization. The connection admission
control interacts with:
- The connection controller from which it receives connection
requests;
- The link resource manager.
Aboul-Magd Expires January 2002 6
Draft-ietf-ipo-ason-00.txt July 2001
5.5 Link Resource Manager Function (LRM)
The role of this function is to keep track of the way link resources
are allocated to connections. The two primary resources that are
held by the link resource manager are capacity and connection
identifiers. The link resource manager records the capacity as seen
by the connection point group agent or access group agent and
controls the allocation of capacity to connections when requested as
part of the connection set-up process. The link resource manager
interacts with:
- The connection admission control function from which it receives
requests for link resources;
- The policing function for the setting and enforcement of policing
parameters for a connection;
- The connection controller that is informed by the link resource
manager that a connection has been admitted or released.
The behaviour of the link resource manager is dependent upon the
type of connection involved and the policies in force for
reservation and priority. As such the behaviour is technology
dependent.
In the case of circuit switching resource management is simple since
the allocation of capacity is automatic when a link connection is
connected to a connection.
The link resource manager function looks after label mappings and
variable capacity connections.
5.6 Connection Point Status Function (CPS)
The role of this function is to provide the connection controller
with visibility of the status of all the connection points on the
boundary of the subnetwork. The underlying CTP or TTP agents
provide the connection point status function. The status is the
state of the connection point as it proceeds through connection set-
up and release.
5.7 Policing Agent Function (PA)
The role of this function is to check that a connection is sending
traffic according to the parameters agreed at connection set-up or
as a result of a modification request. Where a connection violates
the agreed parameters then the policing agent may instigate measures
to correct the situation. Note: this is not needed for a CBR
transport layer network. PA relates to the incoming connection only.
5.8 Protocol Controller Function (PC)
The role of the protocol controller is to provide reliable transfer
of control messages across the network by means of a defined
interface. This permits messages to be tracked and to ensure
Aboul-Magd Expires January 2002 7
Draft-ietf-ipo-ason-00.txt July 2001
expected responses are received or that an exception is reported to
the originator.
Under normal circumstances signaling primitives are passed between
the connection controller and the protocol controller within a sub-
network controller. The protocol controller is semantically
transparent to the messaging primitives as these result in external
protocol messages and vice versa. Signaling messages are passed
between protocol controllers in different sub-network controllers.
Protocol controllers are used to transfer the following information
Route table update messages via a route table update protocol
controller;
- Link resource manager messages (where appropriate as in available
bit rate connections) via a link resource manager protocol
controller;
- Connection control messages via a connection controller protocol
controller.
In addition, different protocol controllers may be implemented for
the following, I-NNI, E-NNI, and UNI.
In the case of a ôfabric controllerö there is an additional
interface, the CCI, between the underlying fabric and the
controller. This, in a single network element, is not subject to
standardization.
6. ASON Control Plane: External Interfaces and Protocols
The ASON CP as shown in Figure 2 defines a set of interfaces:
- User-Network Interface (UNI): UNI runs between the optical client
and the network.
- Internal Node-to-Node Interface (I-NNI): I-NNI defines the
interface between the signaling network elements, i.e. OCC within
the switched optical network.
- External Node-to-Node Interface (E-NNI): E-NNI defines the
interface between ASON control planes in different administration
domains.
- Connection Control Interface (CCI): The CCI defines the interface
between ASON signaling element, i.e. OCC and the transport network
element, i.e. the cross connect.
The different ASON interfaces are described in the next few
sections. Candidate protocols for use at the different interfaces
are also discussed.
6.1 ASON User-Network Interface
Aboul-Magd Expires January 2002 8
Draft-ietf-ipo-ason-00.txt July 2001
ASON UNI allows ASON client to perform a number of functions
including:
- Connection Create: Allows the clients to signal to the network to
create a new connection with specified attributes. Those
attributes might include bandwidth, protection, restoration, and
diversity.
- Connection Delete: Allows ASON clients to signal to the network
the need to delete an already existing connection.
- Connection Modify: Allows ASON clients to signal to the network
the need to modify one or more attribute for an already existing
connection.
- Status Enquiry: Allows ASON clients to enquire the status of an
already existing connection.
Other functions that might be performed at the ASON UNI are, client
registration, address resolution, neighbor and service discovery.
Those functions could be automated or manually configured between
the network and its clients.
Client registration and address resolution are tightly coupled to
the optical network address scheme. Requirements for optical network
addresses and client names are outlined in [7]. In general the
client name (or identification) domain and optical address domain
are decoupled. The client id should be globally unique to allow for
the establishment of end-to-end connections that encompass multiple
administration domains. For security, it is required that the nodal
addresses used for routing within an optical domain do not cross
network boundaries. The notion of closed user groups should also be
included in ASON addressing to allow for the offering of OVPN
services.
Address registration and resolution usually involves some kind of a
directory service. The client uses the registration process to
register his identification with the provider network for a
particular user group or groups. Address resolution involves the
process of translating client names to network addresses. Address
resolution can be performed at clients, edge network element, or at
every administrative boundary entry. It could involves
authentication and policy look up to make sure that a client has the
necessary credentials to join a user group.
ASON UNI realization requires the implementation of a signaling
protocol with sufficient capabilities to satisfy UNI functions. Both
LDP [8] and RSVP-TE [9] have been extended to be used the signaling
protocol across the ASON UNI. The extensions involve the definition
of the necessary TLVs or objects to be used for signaling connection
attributes specific to the optical layer. New messages are also
defined to allow for connection status enquiry. The Optical
Aboul-Magd Expires January 2002 9
Draft-ietf-ipo-ason-00.txt July 2001
Internetworking Forum (OIF) has adopted both protocols in its UNI
1.0 specifications [10].
6.2 ASON Internal Node-to-Node Interface
The I-NNI defines the interface between adjacent optical connection
controls (OCC) in the same network. There are two main aspects of I-
NNI. Those are signaling and routing.
Path selection and setup through the optical network requires a
signaling protocol. Transport networks typically utilize explicit
routing, where path selection can be done either by operator or
software scheduling tools in management systems. IN ASON, end-to-end
optical channels (connections) are requested with certain
constraints. Path selection for a connection request should employ
constrained routing algorithms that balance multiple objectives:
- Conform to constraints such as physical diversity, etc.
- Load balancing of network traffic to achieve the best utilization
of network resources.
- Follow policy decisions on routing such as preferred routes.
To facilitate the automation of the optical connection setup, nodes
in the optical network must have an updated view of its adjacencies
and of the utilization levels at the various links of the network.
This updated view is sometime referred to as state information.
State information dissemination is defined as the manner in which
local physical resource information is disseminated throughout the
network. First the local physical resource map is summarized into
logical link information according to link attributes. This
information can then be distributed to the different nodes in the
network using the control plane transport network IGP.
ASON I-NNI could be based on two key protocols, IP and MPLS. Since
MPLS employs the principle of separation between the control and the
forward planes, its extension to support I-NNI signaling is
feasible. Generalized MPLS [4] defines MPLS extensions to suit types
of label switching other than the in-packet label. Those other types
include, time slot switching, wavelength and waveband switching, and
position switching between fibers. Both CR-LDP [11] and RSVP-TE [12]
have been extended to allow for the request and the binding of
generalized labels. With generalized MPLS, a label switched path
(LSP) is established with the appropriate encoding type (e.g. SONET,
wavelength, etc.). LSP establishment takes into account specific
characteristics that belong to a particular technology.
MPLS traffic engineering requires the availability of routing
protocols that are capable of summarizing link state information in
their databases. Extensions to IP routing protocols, OSPF and IS-IS,
Aboul-Magd Expires January 2002 10
Draft-ietf-ipo-ason-00.txt July 2001
in support of link state information for generalized MPLS are
described in [13, 14].
6.3 ASON External Node-to-Node Interface
E-NNI is an inter-domain interface for use between ASON networks
that are under different network administrations. It is similar to
the UNI interface with some routing functions to allow for the
exchange of reachability information between different domains. BGP
is an IP based protocol that could be used to summarize reachability
information between different ASON domains in the same manner as it
has been in use today for IP networks.
6.4 ASON Connection Control Interface
CCI defines the interface between the ASON signaling element (OCC)
and the transport network elements. Connection control information
is passed over this interface to establish connections between the
ports of the optical transport switch. The CCI is included as part
of ASON control plane because it enables switches of various
capacities and internal complexities to be part of an ASON node.
The protocol running across the CCI must support two essential
functions:
- Adding and deletion of connections.
- Query of port status of the switch.
General Switch Management Protocol (GSMP) [15] fits CCI
requirements. GSMP is a general-purpose protocol that allows a
controller to establish and release connections across a switch.
GSMP is well suited for network architectures that employs label
swapping in the forwarding plane, e.g. ATM, FR, and MPLS. This
property makes GSMP a good fit for generalized label as defined by
generalized MPLS. GSMP extensions for generalized MPLS are yet to be
worked out.
7. ASON/ASTN CP Transport Network (signaling Network)
In this section, we detail some architectural considerations for the
makeup of the transport network that is used to transport the
control plane information. For circuit-based networks, the ability
to have an independent transport network for message transportation
is an important requirement.
The control network represents the transport infrastructure for
control traffic, and can be either in-band or out-of-band. An
implication of this is that the control plane may be supported by a
different physical topology from that of the underlying ASON. There
are fundamental requirements that control networks must satisfy in
order to assure that control plane data can be transported in a
reliable and efficient manner. In the event of control plane failure
Aboul-Magd Expires January 2002 11
Draft-ietf-ipo-ason-00.txt July 2001
(for example, communications channel or control entity failure),
while new connection operations will not be accepted, existing
connections will not be dropped. Control network failure would still
allow dissemination of the failure event to a management system for
maintenance purposes. This implies a need for separate notifications
and status codes for the control plane and ASON. Additional
procedures may also be required for control plane failure recovery.
It is recognized that the inter-working of the control networks is
the first step towards control plane inter-working. To maintain a
certain level of ease, it's desirable to have a common control
network for different domains/sub-networks or types of network.
Typically, control plane and transport functions may co-exist in a
network element. However, this may not be true in the case of a
third party control. This situation needs further study.
Furthermore, addressing issues in the control plane vis--vis the
transport network is also for further study.
ASON CP transport network requirements includes:
- Control plane message transport should be secure. This requirement
stems from the fact that the information exchanged over the
control plane is service-provider specific and security is of
utmost importance.
- Control message transport reliability has to be guaranteed in
almost all situations, even during what might be considered
catastrophic failure scenarios of the controlled network.
- The control traffic transport performance affects connection
management performance. Connection service performance largely
depends on its message transport. Time sensitive operations, such
as protection switching, may need certain QoS guarantees.
Furthermore, a certain level of survivability of the message
transport should be provided in case of control network failure.
- The control network needs to be both upward and downward scalable
in order for the control plane to be scalable. Downward
scalability may be envisioned where the ASON network offers
significant static connections, reducing the need for an extended
control network.
- The control plane protocols shall not assume that the signaling
network topology is identical to that of the transport network.
The control plane protocols MUST operate over a variety of
signaling network topologies.
Given the above requirements, it is critical that the maintenance of
the control network itself not pose a problem to service providers.
As a corollary this means that configuration-intensive operations
should be avoided for the control network.
Aboul-Magd Expires January 2002 12
Draft-ietf-ipo-ason-00.txt July 2001
Common channel signaling links are associated with user channels in
the following ways:
- Associated, whereby signaling messages related to traffic between
two network elements are transferred over signalling links that
directly connect the two network elements
- Non-associated, whereby signaling messages between two network
elements A and B are routed over several signalling links, whilst
traffic signals are routed directly between A and B. The
signalling links used may vary with time and network conditions
- Quasi-associated, whereby signaling messages between nodes A and B
follow a predetermined routeing path over several signalling links
whilst the traffic channels are routed directly between A and B.
Associated signaling may be used where the number of traffic channels
between two network elements is large, thereby allowing a single
signaling channel to be shared amongst a large number of traffic
channels.
Quasi-associated signaling may be used to improve resiliency. For
example consider a signaling channel that has failure mechanisms
independent of the traffic channels. Failure of the signaling channel
will result in loss of signaling capability for all traffic channels
even if all the traffic channels are still functional. Quasi-
associated signaling mitigates against this by employing alternative
signaling routes. In other words the signaling network must be
designed such that failure of a signaling link shall not affect the
traffic channels associated with that signaling channel.
8. Transport Network Survivability
In a transport network, survivability can be controlled by the
ASON/ASTN control plane or by transport network mechanisms that are
independent of the control plane. Survivability can be achieved
either by means of protection, which requires dedicated capacity, or
restoration which uses available spare capacity. Specific
survivability mechanisms such as protection schemes or fast
restoration schemes are beyond the scope of this recommendation.
Soft permanent connections are set-up/torn down in response to
requests initiated by the network management system. As such it is
possible to determine survivability routings using operational
support systems, with explicit path information relayed to the
control plane or by the control plane itself.
In the case of switched connections, survivability and routing are
determined by the control plane.
User requests for explicit survivability mechanisms (e.g. requests
for 1:1, 1+1, ring, mesh protection etc.) are not supported, as the
user should not have access to the topology of the provider network
and in some instances the connection may require different protection
mechanisms for different parts of the connection. However, the user
Aboul-Magd Expires January 2002 13
Draft-ietf-ipo-ason-00.txt July 2001
may request from the provider diverse connections (i.e. with no
common routing).
To provide diverse routing it is necessary to have access to
information relating to the topology of the layer network in which
the soft permanent connection or switched connection resides and all
of the server layer networks including the fiber, cable and duct
(also known as conduit). Full diversity also requires knowledge of
the relationship between buildings/locations and transmission
facilities. Mechanisms to support diverse routing, for those carriers
wishing to support this functionality, may be provided by either the
management plane, for soft permanent connections, or the control
plane for either soft permanent connections or switched connections.
10. Relationship to GMPLS Architecture
The relationship between ASON/ASTN control plane architecture and
GMPLS-based protocols is established in section 6, where it has been
shown how the different GMPLS protocol could be used for the
realization of the different ASON/ASTN external interfaces.
Recently, a GMPLS architecture [16] has been introduced. It is
important to note that there is no real conflict between GMPLS
architecture and the network architecture presented in this draft.
ASON/ASTN provides a functional architecture of a control plane that
allows the establishment of switched paths in optical networks. It
provides the set of external interfaces that are necessary for the
ASTN/ASON network to have a global reach. It does that, however, in a
protocol independent fashion that can be realized in a different ways
provided that its requirements are satisfied.
The GMPLS architecture focuses more on the applications of GMPLS-
defined protocols, e.g. CR-LDP for the setup of generalized LSP
(GLSP) at the different interfaces of the network, e.g. I-NNI, UNI,
etc. It does that in a more comprehensible way than what is described
in section 6 of this draft.
11. Security Considerations
This draft does not introduce any unknown security issues.
12. References
1 Bradner, S., "The Internet Standards Process -- Revision 3", BCP
9, RFC 2026, October 1996.
2 Mayer, M. Ed., "Requirements for Automatic Switched Transport
Networks (ASTN)", ITU G.807/Y.1301, V1.0, May 2001.
Aboul-Magd Expires January 2002 14
Draft-ietf-ipo-ason-00.txt July 2001
3 M. Mayer, Ed., "Architecture for Automatic Switched Optical
Networks (ASON)", G.ason Draft v0.5.1, June 2001
4 Ashwood-Smith, P. et. al., "Generalized MPLS- Signaling
Functional Description", draft-ietf-mpls-generalized-signaling-
04.txt, work in progress, May. 2001
5 Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997
6 Rajagopalan, B. et. al., "IP over Optical Networks: A Framework",
draft-many-ipo-optical-framework-03.txt, work in progress, March.
2001
7 Lazar, M. et. al., "Alternate Addressing Proposal", OIF
Contribution, OIF2001.21, January 2001.
8 Aboul-Magd, O. et. al., "LDP Extensions for Optical User Network
Interface (O-UNI) Signaling", draft-ietf-mpls-ldp-uni-optical-
01.txt, work in progress, July 2001.
9 Yu, J., et. al., "RSVP Extensions in Support of OIF Optical UNI
Signaling", draft-yu-mpls-rsvp-oif-uni-00.txt, work in progress,
Dec. 2000.
10 Rajagopalan, B. Editor, "User Network Interface (UNI) 1.0
Signaling Specifications", OIF Contribution, OIF2000.125.5, June
2001
11 Ashoowd-Smith, P. et. al., "Generalized MPLS Signaling: CR-LDP
Extensions", draft-ietf-mpls-generalized-cr-ldp-03.txt, work in
progress, May 2001
12 Ashwood-Smith, P. et. al., "Generalized MPLS Signaling: RSVP-TE
Extensions", draft-ietf-mpls-generalized-rsvp-te-03.txt, work in
progress, May 2000.
13 Kompella, K. et. al., "IS-IS Extensions in Support of Generalized
MPLS", draft-ietf-isis-gmpls-extensions-01.txt, work in progress,
Nov. 2000.
14 Kompella, K. et. al., "OSPF Extensions in Support of Generalized
MPLS", draft-kompella-ospf-gmpls-extensions-01.txt, work in
progress, Nov. 2000.
15 Doria, A. et. al., "Generalized Switch Management Protocol V3",
draft-ietf-gsmp-08.txt, work in progress, Nov. 2000.
16 Mannie, E., Ed., "Generalized Multi-Protocol Lable Switching
(GMPLS) Architecture" draft-ietf-ccamp-gmpls-architecture-00.txt,
work in progress, June 2001.
Aboul-Magd Expires January 2002 15
Draft-ietf-ipo-ason-00.txt July 2001
13. Author's Addresses
Osama Aboul-Magd
Nortel Networks
P.O. Box 3511, Station C
Ottawa, Ontario, Canada
K1Y-4H7
Phone: 613-763-5827
E.mail: Osama@nortelnetworks.com
Michael Mayer
Nortel Networks
P.O. Box 3511, Station C
Ottawa, Ontario, Canada
K1Y-4H7
Phone: 613-765-4153
Email: mgm@nortelnetworks.com
David Benjamin
Nortel Networks
2351 BOULEVARD ALFRED-NOBEL
ST LAURENT, QUEBEC, CANADA
H4S-2A9
Phone: 514-818-7812
Email: Benjamin@nortelnetworks.com
Bilel Jamoussi
Nortel Networks
600 Technology Park Drive
Billerica, MA 01821, USA
Phone: 978-288-4506
Email: jamoussi@nortelnetworks.com
Ludovico Prattico
Nortel Networks
P.O. Box 3511, Station C
Ottawa, Ontario, Canada
K1Y-4H7
Phone: 613-763-1254
Email: prattico@nortelnetworks.com
Stephen Shew
Nortel Networks
P.O. Box 3511, Station C
Ottawa, Ontario, Canada
K1Y-4H7
Phone: 613-763-2462
Email: sdshew@nortelnetworks.com
Aboul-Magd Expires January 2002 16
Draft-ietf-ipo-ason-00.txt July 2001
Full Copyright Statement
"Copyright (C) The Internet Society (date). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implmentation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into
Aboul-Magd Expires January 2002 17
Html markup produced by rfcmarkup 1.129d, available from
https://tools.ietf.org/tools/rfcmarkup/