Automatic Switched Transport Network (ASTN) allows traffic paths to be set up through a switched network automatically. The term ASTN replaces the term ASON (
Automatically Switched Optical Network) and is often used interchangeably with
GMPLS Generalized Multi-Protocol Label Switching (GMPLS) is a protocol suite extending MPLS to manage further classes of interfaces and switching technologies other than packet interfaces and switching, such as time-division multiplexing, layer-2 switchin ...
(Generalized
MPLS
Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on labels rather than network addresses. Whereas network addresses identify endpoints the labels identif ...
). This is not completely correct as GMPLS is a family of protocols, but ASON/ASTN is an optical/transport network architecture. The requirements of the ASON/ASTN architecture can be satisfied using GMPLS protocols developed by the
IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...
or by GMPLS protocols that have been modified by the
ITU. Furthermore, the GMPLS protocols are applicable to optical and non-optical (e.g., packet and frame) networks, and can be used in transport or client networks. Thus, GMPLS is a wider concept than ASTN.
Traditionally, creating traffic paths through a series of Network Elements has involved configuration of individual cross-connects on each Network Element. ASTN allows the user to specify the start point, end point and bandwidth required, and the ASTN agent on the Network Elements will allocate the path through the network, provisioning the traffic path, setting up cross-connects, and allocating bandwidth from the paths for the user requested service. The actual path that the traffic will take through the network is not specified by the user.
Changes to the network (adding/removing nodes) will be taken into account by the ASTN agents in the network, but do not need to be considered by the user. This gives the user far more flexibility when allocating user bandwidth to provide services demanded by the customer.
GMPLS consist of several protocols, including routing protocols (
OSPF-TE or
ISIS-TE), link management protocols (LMP
[RFC 4204]
"Link Management Protocol"
/ref>), and a reservation/label distribution protocol (RSVP-TE
Resource Reservation Protocol - Traffic Engineering is an extension of the Resource Reservation Protocol (RSVP) for traffic engineering. It supports the reservation of resources across an IP network. Applications running on IP end systems can us ...
). The reservation/label distribution protocol CR-LDP has now been deprecated by the IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...
in ''RFC 3468'' [RFC 3468]
"The Multiprotocol Label Switching (MPLS) Working Group decision on MPLS signaling protocols"
/ref> (February 2003) and IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...
GMPLS working group decided to focus purely on RSVP-TE.
The GMPLS architecture is defined in ''RFC 3945''.[RFC 394]
"Generalized Multi-Protocol Label Switching (GMPLS) Architecture"
/ref>
References
Further reading
*''GMPLS: Architecture and Applications'' by Adrian Farrel and Igor Bryskin
External links
From MPLS to GMPLS
(pdf)
GMPLS Unified Control Plane
(pdf)
Evolution to All-optical Networking
(pdf)
{{DEFAULTSORT:Automatic Switched-Transport Network
Telephony
MPLS networking
Internet Standards
Network protocols