OSA's Digital Library

Optics Express

Optics Express

  • Editor: Michael Duncan
  • Vol. 13, Iss. 5 — Mar. 7, 2005
  • pp: 1702–1709
« Show journal navigation

Reservation information sharing enhancement for deflection routing in OBS network

onghui Gao, Hanyi Zhang, and Zhiyu Zhou  »View Author Affiliations


Optics Express, Vol. 13, Issue 5, pp. 1702-1709 (2005)
http://dx.doi.org/10.1364/OPEX.13.001702


View Full Text Article

Acrobat PDF (115 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

The resource contention problem is critical in Just-Enough-Time (JET) based optical burst switching (OBS) networks. Although deflection routing (DR) reduces the contention probability in some degree, it does not give much improvement under heavy traffic load. This paper analyzed the inducement causing contention in OBS networks, and proposed Resource Information Sharing Enhancement (RISE) scheme. Theoretical analysis shows that this scheme achieves shorter length of the detour path than normal DR. We simulated this scheme on both full mesh network and practical 14-node NSFNET. The simulation results show that it gives at best 2 orders magnitude improvement in reducing the burst contention probability over its previous routing approaches.

© 2005 Optical Society of America

1. Introduction

1.1 JET based OBS networks

1.2 Deflection routing

To resolve the resource contention problem, some ideas based on deflection routing (DR) have been proposed to reroute the burst from the congested node to its destination [4

4. X. Wang et al., “A Deflection Routing Protocol for Optical Bursts in WDM Networks,” in proceeding of Fifth Optoelectronics and Communications Conference (Makuhari, Japan, 2000), pp. 94–95.

10

10. S. Lee et al., “Contention-Based Limited Deflection Routing in OBS Networks,” in proceeding of the IEEE Globecom (San Francisco, 2003), pp. 2633–2637.

]. DR has its advantage at relatively light network traffic load, when a detour path is easily to be found and thus fewer retransmissions are needed. However, its disadvantages are obvious as follows. First, when the burst is deflected to a detour, the number of total hops may increase notably in some topology, and the offset time will not be enough for the control packet to setup the connection. Second, as each node has no knowledge of the resource information at other nodes, the deflection is blindfold. Therefore, DR degrades the network performance in heavy traffic load conditions [9

9. Yang Chen et al., “Performance Analysis of Optical Burst Switched Node with Deflection Routing,” in proceeding of ICC’03 (Anchorage, USA, 2003), pp. 1355–1359.

, 10

10. S. Lee et al., “Contention-Based Limited Deflection Routing in OBS Networks,” in proceeding of the IEEE Globecom (San Francisco, 2003), pp. 2633–2637.

].

1.3 Our contribution

In this paper, we propose a new scheme called Reservation Information Sharing Enhancement (RISE) to resolve the resource contention problem. RISE consists of information exchanging mechanism and routing selection algorithm for contention avoidance. In this scheme, we designed partial spread of the reservation information, which can be used to predetermine if an incoming burst will be blocked at its next-hop node. We simulated RISE scheme on 3×4 mesh networks and 14-node NSFNET. The results show that RISE gives at best 2 orders magnitude improvement in reducing the contention probability.

The rest of the paper is organized as follows. Section 2 discusses the issues in the current resolutions for resource contention in JET based OBS network. Section 3 describes our RISE scheme for resolving resource contention. Section 4 evaluates the performances of our scheme and Section 5 concludes the paper.

2. Related work

2.1 JET reservation protocol

2.2 Issues analysis of DR

Fig. 1. Performance degradation of DR in practical topology

3. Reservation information sharing enhancement

The essence distinguishes OBS from circuit switching is the capability to handle the real-time bursty traffic. This requires unacknowledged connection setup and no resource information flooding through the network, which ultimately results in the resource contention problem. If a control packet can be transmitted to its neighbor and processed in much shorter time than burst transmission duration, it is effective to avoid contention by sharing reservation information between neighbors.

3.1 Information sharing between neighboring nodes

There are still differences in information exchange process between OBS and circuit switching. In circuit switching, both the setup and teardown process of a connection are explicit with some certain signals. While in JET based OBS network, the teardown of a connection is generally implicit by estimating the time of the burst transmission duration [11

11. C. Qiao et al., “Choices, features and issues in optical burst switching,” Opt. Net. Mag , 1, 36–44 (2000).

]. Moreover, the basic parameters such as starting and ending transmission time are necessary for checking the admission control of a burst. So a timer is required to manipulate the database of the resource information from neighbors. When an information packet is received, the peer delay of the packet and processing time must be considered before inserting the reservation item into the database. When a burst is transmitted completely at its neighbor, the corresponding reservation item in the local database will be deleted automatically by the timer.

3.2 Congestion precognition mechanism

The admission control function determines whether a burst has enough resource to be transmitted through certain output port. The input parameters of this function include the OFFSET time between the control packet and its burst, and the transmission DURATION of the burst. The details of this function are listed as below.

The essence of the function is to determine whether the current burst overlaps with former burst. The inequation offset[j] >OFFSET+DURATION indicates that the current burst will be transmitted completely before the arrival of the former burst in the jth Reserve_item; while OFFSET>offset[j]+duration[j] indicates the opposite. Otherwise, the bursts will overlap. For sake of reliability, we can add a small gap µ between two consecutive bursts to avoid bursts overlapping because of inaccuracy of the timer. And if FDL can be applied in the network, the longest delay interval DFDL should also be considered. Thus, the determination condition can be written as: (offset[j]+DFDL >OFFSET+DURATION+µ) and (OFFSET+DFDL >offset[j]+duration[j]+µ).

Definitions:

Nw : the number of wavelengths multiplexed in the output fiber port; Reserve_seq[w]: the resource reservation sequence of the wavelength w; Reserve_item i: the ith reservation item in the Reserve_seq; offset[j]: the offset time of the jth Reserve_item; duration[j]: the burst duration of the jth Reserve_item.

Function:

ADMISSION_CONTROL (time OFFSET, time DURATION)

{

FOR (wavelength w=0 to Nw -1)

{

IF (Reserve_seq[w] is NULL) Return TRUE;

ELSE FOR (each Reserve_item j in Reserve_seq[w])

{

if ((offset[j] > OFFSET+DURATION) OR

(OFFSET > offset[j]+duration[j]))

Return TRUE;

}

}

Return FALSE;

}

Fig. 2. Flowchart for RISE scheme

3.3 Improvement analysis of RISE

In this section, the improvement of RISE will be proved. In case of congestion, the burst will be redirected to a detour path. The longer detour path will result in larger contention probability in the topology. The length of detour path in RISE is no more than DR is proved as below (Fig. 3).

(SAA2D)R(S,D)G¯
(*)

Fig. 3. Length of detour path comparison between RISE and DR

3.4 Scalability consideration

In the normal connection setup process in OBS network, the control packet will be handed on along the specified route and processed. In our new scheme, after each intermediate node reserves resources and configures the optical cross-connect, it should also share this information with its neighbors excluding the upstream and downstream node along the route. The information transmission adds the total traffic load of the signaling network. In this part, the scalability problem is considered for the incremental signaling traffic versus network scale.

4. Performance evaluation

Fig. 4. Simulation on 3×4 full mesh network topology

Although 3×4 full mesh network can give an example to evaluate the performance, it has larger network connection degree Dc than practical network. So we also simulate the three models on 14-node NSFNET as shown in Fig. 1. Because of less Dc in 14-node NSFNET, the second shortest path becomes longer and the performance improvement effect by routing protocol is weakened. The simulation result is shown in Fig. 5, where DR can not enhance the network contention performance. However, our new scheme still works well form light to relatively heavy traffic load with certain improvement. Also, RISE does not work under very high loads (for instance, when contention probability is over 0.1).

Fig. 5. Burst contention probability comparison in 14-node NSFNET

5. Conclusion

Acknowledgments

This work is supported by Tsinghua & Bell Labs Research China Joint Lab, NNSF of China (60132020, 90104003), and 863 Program (2003 AA 122220).

References and Links

1.

C. Qiao and M. Yoo, “Optical burst switching (OBS)-a new paradigm for an optical Internet,” J. High Speed Networks , 8, 69–84 (1999).

2.

Myungsik Yoo et al., “Just-Enough-Time (JET): A High Speed Protocol for Bursty Traffic in Optical Networks,” in proceeding of IEEE/LEOS Conf. on Technologies for a Global Information Infrastructure (1997), pp. 26–27.

3.

ITU-T Rec. G.8080/Y.1304, “Architecture for the Automatically Switched Optical Network,” (Geneva, 2001).

4.

X. Wang et al., “A Deflection Routing Protocol for Optical Bursts in WDM Networks,” in proceeding of Fifth Optoelectronics and Communications Conference (Makuhari, Japan, 2000), pp. 94–95.

5.

X. Wang et al., “Burst optical deflection routing protocol for wavelength routing WDM networks,” Opt. Net. Mag , 3, 12–18 (2002).

6.

M. Yoo et al., “A comparative study of contention resolution policies in optical burst switched WDM networks,” in proceeding of Conf. on Terabit Optical Networking (2000), 4213, pp. 124–135.

7.

S. Kim et al., “Contention resolution for optical burst switching networks using alternative routing,” in proceeding of IEEE Int. Conf. Communications (New York, 2002), pp. 2679–2681.

8.

Ching-Fang Hsu et al., “On the deflection routing in QoS supported optical burst-switched networks,” in proceeding of ICC’02 (2002), pp. 2786–2790.

9.

Yang Chen et al., “Performance Analysis of Optical Burst Switched Node with Deflection Routing,” in proceeding of ICC’03 (Anchorage, USA, 2003), pp. 1355–1359.

10.

S. Lee et al., “Contention-Based Limited Deflection Routing in OBS Networks,” in proceeding of the IEEE Globecom (San Francisco, 2003), pp. 2633–2637.

11.

C. Qiao et al., “Choices, features and issues in optical burst switching,” Opt. Net. Mag , 1, 36–44 (2000).

12.

Network Simulator, NS-2, available at http://www.isi.edu/nsnam/ns.

OCIS Codes
(060.4250) Fiber optics and optical communications : Networks
(060.4510) Fiber optics and optical communications : Optical communications

ToC Category:
Research Papers

History
Original Manuscript: January 4, 2005
Revised Manuscript: February 25, 2005
Published: March 7, 2005

Citation
Donghui Gao, Hanyi Zhang, and Zhiyu Zhou, "Reservation information sharing enhancement for deflection routing in OBS network," Opt. Express 13, 1702-1709 (2005)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-13-5-1702


Sort:  Journal  |  Reset  

References

  1. C. Qiao and M. Yoo, �??Optical burst switching (OBS) - a new paradigm for an optical Internet,�?? J. High Speed Networks, 8, 69-84 (1999).
  2. Myungsik Yoo et al., �??Just-Enough-Time (JET): A High Speed Protocol for Bursty Traffic in Optical Networks,�?? in proceeding of IEEE/LEOS Conf. on Technologies for a Global Information Infrastructure (1997), pp. 26-27.
  3. ITU-T Rec. G.8080/Y.1304, �??Architecture for the Automatically Switched Optical Network,�?? (Geneva, 2001).
  4. X. Wang et al., �??A Deflection Routing Protocol for Optical Bursts in WDM Networks,�?? in proceeding of Fifth Optoelectronics and Communications Conference (Makuhari, Japan, 2000), pp. 94-95.
  5. X. Wang et al., �??Burst optical deflection routing protocol for wavelength routing WDM networks,�?? Opt. Net. Mag., 3, 12-18 (2002).
  6. M. Yoo et al., �??A comparative study of contention resolution policies in optical burst switched WDM networks,�?? in proceeding of Conf. on Terabit Optical Networking (2000), 4213, pp. 124-135.
  7. S. Kim et al., �??Contention resolution for optical burst switching networks using alternative routing,�?? in proceeding of IEEE Int. Conf. Communications (New York, 2002), pp. 2679-2681.
  8. Ching-Fang Hsu et al., �??On the deflection routing in QoS supported optical burst-switched networks,�?? in proceeding of ICC�??02 (2002), pp. 2786�??2790.
  9. Yang Chen et al., �??Performance Analysis of Optical Burst Switched Node with Deflection Routing,�?? in proceeding of ICC'03 (Anchorage, USA, 2003), pp. 1355-1359.
  10. S. Lee et al., �??Contention-Based Limited Deflection Routing in OBS Networks,�?? in proceeding of the IEEE Globecom (San Francisco, 2003), pp. 2633-2637.
  11. C. Qiao et al., �??Choices, features and issues in optical burst switching,�?? Opt. Net. Mag, 1, 36-44 (2000).
  12. Network Simulator, NS-2, available at <a href="http://www.isi.edu/nsnam/ns/">http://www.isi.edu/nsnam/ns/</a>

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited