Internet Draft Jun Kyun Choi Document: draft-choi-gsmp-optical-extension-00.txt Min Ho Kang Expiration Date: December 2002 Gyu Myoung Lee Jung Yul Choi ICU Young Wook Cha ANU Woo Seop Rhee ETRI June 2002 Extension of GSMP for optical burst switching Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC-2026. 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 obsolete 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. Abstract In this draft, we propose the extension of General Switch Management Protocol (GSMP) for optical data burst switching control. This document describes node architecture and reservation management using GSMP interface for data burst switching in optical domain. Particularly, we propose a reservation request message which is extended to the existing GSMP protocol. It contains the information about offset time and burst length to control data burst in optical switch. Conventions 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. Choi et al Expires - December 2002 [Page 1] Extension of GSMP for optical burst switching June 2002 Table of Contents 1. Introduction.....................................................3 2. Switch control architecture......................................3 3. Reservation management for optical burst switching using GSMP v3.5 3.1. Reservation methods.........................................5 3.2. Reservation Request Message for optical burst switching.....5 4. Other considerations.............................................8 5. Security Considerations..........................................8 Appendix. Data burst switching in optical domain....................9 References.........................................................13 Acknowledgments....................................................13 Author's Addresses.................................................14 Choi et al Expires - December 2002 [Page 2] Extension of GSMP for optical burst switching June 2002 1. Introduction The General Switch Management Protocol (GSMP), which is a general- purpose protocol to control a label switch, allows a controller to establish, release, and reserve connections across the switch [1]. It also provides several capabilities for connection management, reservation management, management, status and event management, and configuration so as to satisfy the requested capabilities and control the switch. The evolution form of GSMP has been studied to apply in optical domain as well as in electric domain [2]. The existing GSMP SHOUD be extended to support of optical, SONET/SDH, and IP packet, TDM data. The GSMP controller is connected with OXC and needs to be extended to establish a connection in optical domain. Recently, data burst switching technology has been emerging to utilize resources and transport data more efficiently than the existing circuit switching [3]-[6]. Such a data burst switching is recognized an alternative switching technology due to the limitation of optical devices before evolving into optical packet switching. This draft intends to describe the required elements and updates to GSMP for high-speed data burst switching. It requires a new reservation scheme for a connection in a switch fabric in real time. In optical domain, there are several types of method to establish a connection before switching data burst [3]-[6]. However we consider the general method which can allow any types of burst switching technology. For doing so, in this draft, we consider a reservation mechanism in the GSMP and requested updates on the message. A switch controller on a node to provide the required functions for switching data burst is illustrated. Finally we briefly refer to the required elements to be expanded in optical domain. 2. Switch control architecture Figure 1 illustrates a node architecture that is capable of high- speed data burst switching based on GSMP interface. This node constitutes optical switching elements that enable data burst switching in real time and control plane that has signaling protocol part and data burst switching controller part. Between two blocks, GSMP master and slave controller perform all required switching functions for making it possible to switching data burst in real time. The detailed description of each block is following. The key functions of data burst switching controller are as follows. The ingress node assembles IP packets into bursts. When the burst is at the head of the burst queue, this controller determines the offset time value to be used for this burst and launch a control packet that contains information about this offset time, the length of the burst, and routing information [7]. It also transmits the control information to the GSMP controller in control plane. Choi et al Expires - December 2002 [Page 3] Extension of GSMP for optical burst switching June 2002 GMPLS Signaling protocol, such as CR-LDP and RSVP-TE, which supports optical switching is used in control plane. This signaling protocol MUST setup optical label switched path (LSP) before data transmission and release resources. We use the GSMP interface for real-time optical switch control. In this interface which is composed of master and slave, the controller (e.g., GSMP Master) issues the reservation request message to the optical switch (e.g., GSMP Slave). The switch replies with a response message indicating either a successful result or a failure. We use the existing GSMP protocol procedure but a particular message MUST be extended to include the required information for data burst switching in optical switching element. Data burst switching unit in optical switching element executes the control commands received by GSMP interface. +------------------------------+ | Control plane | | +------------+ | | | Signaling | | ----------->| | Protocol | |-----------> | +------------+ | | +--------------------------+ | ----------->| | Data Burst | |-----------> | | Switching Controller | | | +--------------------------+ | | +--------------------------+ | | | GSMP Master | | | +--------------------------+ | +---------------------^--------+ | GSMP | | Message | | | +--------V---------------------+ | +--------------------------+ | | | GSMP Slave | | | +--------------------------+ | | +--------------------------+ | | | Data Burst Switching Unit| | | +--------------------------+ | | --- --- | ---------->| \ / |----------> | \ / | ---------->| \ |----------> | / \ | ---------->| / \ |----------> | --- --- | +------------------------------+ Optical Switching Element Figure 1. Node architecture for burst switching using GSMP interface Choi et al Expires - December 2002 [Page 4] Extension of GSMP for optical burst switching June 2002 3. Reservation management for optical burst switching using GSMP v3 3.1. Reservation methods Optical data burst switching can be implemented by reserving bandwidth when a connection request is arrived at an ingress node. During reservation process in intermediate nodes each GSMP switch controller should control bandwidth reservation management for the connection. There are several reservation schemes for data burst switching in real time [3]-[6]. They differ from the way of indicating the end of a burst and the allocation time of a WDM channel start. However, a common feature is that bandwidth for data burst is reserved using a one-way reservation process and a burst can cut through intermediate nodes. In the existing fast circuit switching for data burst, when an intermediate node receives a connection request message, GSMP controller makes use of a reservation management for reserving a bandwidth for the connection. The existing defined reservation message can be applied for reserving and establishing a connection in this case. After sending the whole data burst the following connection release message is sent to the destination node to release the reserve bandwidth and disconnect the connection. The whole process of reservation management and control follows that defined in GSMP v3 [1]. The above data burst switching based on the fast circuit switching reserves the whole bandwidth from the time that receives a connection request message and to the time that receives a connection release message. Therefore it wastes the bandwidth excessively. A new data burst switching technology that overcomes the shortcoming has been proposed and studied [3]-[5]. In this scheme, information about the start time for bandwidth reservation the exact duration of data burst is delivered in control packet. A node that receives such a control packet reserves resource to establish and release a connection more delicate duration using GSMP control mechanism. Since the control packet already contains the duration of data burst, an explicit release message does not required. Even though several switching options for data burst, we consider a general reservation scheme which allows all kinds of switching techniques. 3.2. Reservation Request Message for optical burst switching In this section we define a required elements and updates to the existing GSMP and propose an extended Reservation Request message in order to enable such a optical data burst switching. The Reservation Request message creates a Reservation in the switch and reserves switch resources for a connection that may Choi et al Expires - December 2002 [Page 5] Extension of GSMP for optical burst switching June 2002 later be established using an Add Branch message [1]. In optical data burst switching, the Reservation Request Message is: Message Type = 70 It uses the same message type as the existing message. The Reservation Request message has the following format for the request message: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version | Message Type | Result | Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Partition ID | Transaction Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |I| SubMessage Number | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Port Session Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reservation ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Input Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Input Service Selector | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Output Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Output Service Selector | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |IQS|OQS|P|x|N|O| Adaptation Method | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |x|S|M|B| | +-+-+-+-+ Input Label | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |x|S|M|R| | +-+-+-+-+ Output Label | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ When the value of either IQS or OQS is set to 0b10 then the following Traffic Parameters Block is appended to the above message: Choi et al Expires - December 2002 [Page 6] Extension of GSMP for optical burst switching June 2002 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Input TC Flags |x x x x x x x x x x x x x x x x x x x x x x x x| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Input Traffic Parameters Block ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Output TC Flags|x x x x x x x x x x x x x x x x x x x x x x x x| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Output Traffic Parameters Block ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Note: Field and Parameters will not be explained in this draft. Please refer to GSMP v3 [1] for details. We define the new service to support optical data burst switching. This service includes the following definitions. Service Identifier The new reference number which is used to identify optical data burst switching in GSMP messages MUST be defined. Example: Optical Burst Switching - Service ID : XXXX Service Characteristics - see Appendix. Traffic Parameters - Offset Time (T) - Burst Length (L) QoS Parameters - TBD. Traffic Controls - TBD. Format and encoding of the Traffic Parameters is: Choi et al Expires - December 2002 [Page 7] Extension of GSMP for optical burst switching June 2002 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Offset Time (T) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Burst Length (L) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Offset Time (T) This field is the time between each burst and its control packet. Burst Length (L) This field is the time duration of data burst 4. Other considerations This draft focus on reservation procedures to control data burst switching element. To support data burst switching control, the switching element is controlled and managed by GSMP protocol without other control protocol. This mechanism allows GSMP controller of IPû based control plane to direct control optical switching elements. Several concepts for optical switching such as optical labels and service and resource abstractions SHOULD be extended to GSMP [2]. We are studying about these issues. 5. Security Considerations This document does not have any security concerns. The security requirements using this document are described in the referenced documents. Choi et al Expires - December 2002 [Page 8] Extension of GSMP for optical burst switching June 2002 Appendix. Data burst switching in optical domain 1. Definition and features of optical burst switching Data burst switching in optical domain is called as an optical burst switching (OBS). Burst switching, as opposed to circuit or packet switching, implies that the network is capable of switching variable length of data. Basically, the core idea of optical burst switching is to use no buffers inside the network and to switch variable length of bursts on the flying using a reservation mechanism. Intermediate nodes are only configured for a short period of time, just enough to pass data burst, and are available to switch other data bursts immediately after. In present day, packet switching in optical domain has severe limitations on optical devices, such as the lack of optical memory, difficulty of synchronization and packet header processing. Therefore, no buffering in a node is the main advantage of optical burst switching to implement. Compared with packet switching and circuit switching, optical burst switching has the following differences [4]; A data burst has an intermediate granularity. Bandwidth is reserved in one-way process that a burst can be sent without an acknowledgement for a successful reservation. A burst passes through intermediate nodes without being buffered. Optical burst switching, compared to optical circuit switching based on wavelength routing, can achieve better bandwidth utilization because it allows statistical sharing of each wavelength among flows of bursts that may otherwise consume several wavelength. In OBS, a data burst will have a shorter end-to-end latency since the offset time used is often much smaller than the needed time to set up a path in wavelength-routed networks. On the other hand, optical burst switching has lower control overhead compared to optical packet switching because the burst size can be variable and usually longer than packet size. Moreover, a control packet and its corresponding data burst can be loosely coupled in both space (by using out of band signaling) and time (timing gap between control packet and data burst) than a header and its payload in optical packet switching. Therefore, the requirements for processing control packets and synchronizing between data bursts can be less strict than those for processing packet headers and synchronizing between packets. 2. Types of optical burst switching technology Various types of optical burst switching technology have been proposed and they are distinguished by the way of indicating the end of a burst and the allocation time of a WDM channel start [3]-[6]. That is, how to open a connection and how to close the connection are the key features of them. A common feature is that bandwidth is reserved at the burst level using a one-way reservation process and a burst can cut through intermediate nodes. Choi et al Expires - December 2002 [Page 9] Extension of GSMP for optical burst switching June 2002 We briefly introduce three representative data burst switching technologies and consider implementing aspect. First, burst switching based on "tell-and-go (TAG)" is similar to fast circuit switching not requiring acknowledgement [3]-[4]. This switching scheme is also called as just-in-time (JIT) [6]. A source node first sends a control packet (or signaling message) just ahead of the data burst in order to reserve bandwidth for a requested connection. Then a corresponding data burst is transmitted without waiting for the acknowledgement that bandwidth has been successfully reserved for the connection. This scheme eliminates the round-trip waiting time before the information is transmitted. The switching fabric in the switches is configured for the incoming data burst as soon as the first signaling message announcing the data burst is received. Finally the source node sends a release message to explicitly release the reserved bandwidth. The operational mechanism is illustrated in Figure 2 [6]. A B C D setup <-----> |\ | | \ | | \ switch | | \ configured| | | | |------++ | | |\ ||\ | | | \ || \ | | | | \ || \ V | V | \| +------+-- processing | \ ++-----+-- delay | \ || | ^ | \|| | | | \ Data \ | | \ burst \ | |\ \ \ | | \ ||\ | | \ || \ | | ++ \ | | \ |\ | | \ || \ | | \|| \ | | <---> ++ | | release \ | | \ | | | A; source node, B,C; intermediate node, D; destination node Figure 2. Optical burst switching base on JIT Choi et al Expires - December 2002 [Page 10] Extension of GSMP for optical burst switching June 2002 Let us brief touch a function of a scheduler in an OBS node. The scheduler needs to keep state information for each data burst traversing it in order to configure the switching fabric to route the data burst [6]. This switching scheme requires a single on/off bit for each switching fabric involved in routing a particular data burst; on implies the switching element is busy routing a data burst, off implies the switching element is free to route a new data burst. For implementing the JIT, the signaling protocol functions and signaling messages are defined in [6]. Basic functions of signaling protocol are session declaration, path setup, data transmission, state maintenance, and path release. The basic message types are session declaration, setup, setup_ack, declaration_ack, connect, session release, release, keepalive, and failure. Second, in in-band-terminator based burst switching, control information for establishing a connection is sent as either in-band control or out-of-band control, followed by a burst which contains an in-band-terminator (IBT) to indicate the end of the burst [3]-[4]. Bandwidth is reserved as soon as the control information is processed, and released as soon as the IBT is detected. A challenge of implementing IBT-based burst switching in optical networks is to optically recognize the IBT, which requires optical processing. Finally, in reserved-a-fixed-duration (RFD) based on burst switching, a control packet is sent first to reserve bandwidth, followed by data after an offset time [3]-[6]. The bandwidth is reserved for a duration specified by the control packet. With offset time and data burst duration information to predict the star time and end time of the data burst this scheme can utilize resource more efficiently than the above switching schemes. Because this scheme reserves the resource for the connection for requested data burst just enough time for transmitting the data burst. Therefore, it is also called a just- enough-time (JET) burst switching. As such, this scheme does not need any release or termination mechanism. By choosing the offset time among the data bursts with different services quality of service can be provided and the probability of successful transmission of the burst through the network [3]. The two representative features are delayed reservation which reserves the bandwidth on each link just for the data burst duration after offset time and delay of the arrival of the data burst which reduces blocking probability. However, one drawback of this switching is implementation complexity. Choi et al Expires - December 2002 [Page 11] Extension of GSMP for optical burst switching June 2002 A B C D setup <-----> |\ | | \ | | \ switch | | \ configured| | | | | | | | |\ | \ | | | \ ++ \ | | | | \ || \ V | V | \| |------+-- processing | \ |------+-- delay | \ ++ | ^ |\ \|| | | | \ Data \ | | \ burst \ | | \ \ | | ||\ | | ++ \ | | \ | | |\ | | || \ | | ++ \ | | | | | A; source node, B,C; intermediate node, D; destination node Figure 3. Optical burst switching base on JET 3. Implementing consideration of optical burst switching In Optical burst switching a switch fabric should operate and reconfigure in nanoseconds, and hence can support of the dynamic data burst transmission. Requirements of optical switching device for implement OBS are following; fast reconfigurability, low-loss and negligible polarization effects, wavelength independence, transfer of individual wavelengths or wavelength bundles, simple to manufacture, competitive const, and so on [8]. The switching device technology needs to be complemented by a switch fabric architecture that combines the individual optical switching device technology and delivers the capabilities of OBS. The burst switching capable switch fabric should scale to several hundreds of ports and intelligent scheduling algorithms are needed to control the reconfiguration of switching elements. Choi et al Expires - December 2002 [Page 12] Extension of GSMP for optical burst switching June 2002 References [1] Avri Doria., et al. "General Switch Management Protocol V3", Internet-Draft draft-ietf-gsmp-11, work in progress, December 2001. [2] Georg Kullgren, et al. "Requirements for adding optical support to GSMPv3", Internet-Draft draft-ietf-gsmp-reqs-01, work in progress, February 2002. [3] C. Qiao, M. Yoo, "Choice, and Feature and Issues in Optical Burst Switching", Optical Net. Mag., vol.1, No.2, Apr.2000, pp.36-44. [4] C. Qiao, "Labeled Optical Burst Switching for IP over WDM Integration", IEEE Comm. Mag., Sept. 2000, pp.104~114. [5] Yijun Xiong, Marc Vandenhoute, Hakki C. Cankaya, "Control Architecture in Optical Burst-Switched WDM Networks", IEEE JSAC, Vol.18, No.10, Oct. 2000. [6] Ilia Baldine, George N. Rouskas, Harry G. Perros, Dan Stevension, "JumpStart: A Just-in-time Signaling Architecture for WDM Burst- Switching Networks", IEEE Comm. Mag., Fab. 2002. [7] Sanjeev Verma, et al. "Optical burst switching: a viable solution for terabit IP backbone", IEEE network, pp. 48-53, Nov/Dec 2000. [8] Albert Leon-Garcia, "Photonic Burst Switching", whitepaper, Accelight networks, March 2001. Acknowledgments This work was supported in part by the Korean Science and Engineering Foundation (KOSEF) through OIRC project. Choi et al Expires - December 2002 [Page 13] Extension of GSMP for optical burst switching June 2002 Author's Addresses Jun Kyun Choi Information and Communications University (ICU) 58-4 Hwa Ahm Dong, Yuseong, Daejeon Korea 305-732 Phone: +82-42-866-6122 Email: jkchoi@icu.ac.kr Min Ho Kang Information and Communications University (ICU) 58-4 Hwa Ahm Dong, Yuseong, Daejeon Korea 305-732 Phone: +82-42-866-6136 Email: mhkang@icu.ac.kr Gyu Myoung Lee Information and Communications University (ICU) 58-4 Hwa Ahm Dong, Yuseong, Daejeon Korea 305-732 Phone: +82-42-866-6231 Email: gmlee@icu.ac.kr Jung Yul Choi Information and Communications University (ICU) 58-4 Hwa Ahm Dong, Yuseong, Daejeon Korea 305-732 Phone: +82-42-866-6208 Email: passjay@icu.ac.kr Young Wook Cha Andong National University (ANU) 388 Song-chon Dong, Andong, Kyungsangbuk-do Korea 760-749 Phone: +82-54-820-5714 Email: ywcha@andong.ac.kr Woo Seop Rhee Electronics and Telecommunications Research Institute (ETRI) 161 Kajeong, Youseong, Daejeon Korea 305-350 Phone: +82-42-860-5324 Email: wsrhee@etri.re.kr Choi et al Expires - December 2002 [Page 14] Extension of GSMP for optical burst switching June 2002 Full Copyright Statement "Copyright (C) The Internet Society 2002. 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 implementation 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 Document: draft-choi-gsmp-optical-extension-00.txt Expiration Date: December 2002 Choi et al Expires - December 2002 [Page 15]