Pub Date : 2005-12-27DOI: 10.1109/DRCN.2005.1563861
A. Urra, E. Calle, J. Marzo
In this paper, different recovery methods applied at different network layers and time scales are used in order to enhance the network reliability. Each layer deploys its own fault management methods. However, current recovery methods are applied to only a specific layer. New protection schemes, based on the proposed partial disjoint path algorithm, are defined in order to avoid protection duplications in a multi-layer scenario. The new protection schemes also encompass shared segment backup computation and shared risk link group identification. A complete set of experiments proves the efficiency of the proposed methods in relation with previous ones, in terms of resources used to protect the network, the failure recovery time and the request rejection ratio.
{"title":"Partial disjoint path for multi-layer protection in GMPLS networks","authors":"A. Urra, E. Calle, J. Marzo","doi":"10.1109/DRCN.2005.1563861","DOIUrl":"https://doi.org/10.1109/DRCN.2005.1563861","url":null,"abstract":"In this paper, different recovery methods applied at different network layers and time scales are used in order to enhance the network reliability. Each layer deploys its own fault management methods. However, current recovery methods are applied to only a specific layer. New protection schemes, based on the proposed partial disjoint path algorithm, are defined in order to avoid protection duplications in a multi-layer scenario. The new protection schemes also encompass shared segment backup computation and shared risk link group identification. A complete set of experiments proves the efficiency of the proposed methods in relation with previous ones, in terms of resources used to protect the network, the failure recovery time and the request rejection ratio.","PeriodicalId":415896,"journal":{"name":"DRCN 2005). Proceedings.5th International Workshop on Design of Reliable Communication Networks, 2005.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127031876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-12-14DOI: 10.1109/DRCN.2005.1563902
C. Gruber, A. Koster, S. Orlowski, R. Wessäly, A. Zymolka
In this paper, we compare the new resilience mechanism demand-wise shared protection (DSP) with dedicated and shared path protection. The computational study on five realistic network planning scenarios reveals that that the best solutions for DSP are on average 15% percent better than the corresponding 1+1 dedicated path protection solutions, and only 15% percent worse than shared path protection.
{"title":"A computational study for demand-wise shared protection","authors":"C. Gruber, A. Koster, S. Orlowski, R. Wessäly, A. Zymolka","doi":"10.1109/DRCN.2005.1563902","DOIUrl":"https://doi.org/10.1109/DRCN.2005.1563902","url":null,"abstract":"In this paper, we compare the new resilience mechanism demand-wise shared protection (DSP) with dedicated and shared path protection. The computational study on five realistic network planning scenarios reveals that that the best solutions for DSP are on average 15% percent better than the corresponding 1+1 dedicated path protection solutions, and only 15% percent worse than shared path protection.","PeriodicalId":415896,"journal":{"name":"DRCN 2005). Proceedings.5th International Workshop on Design of Reliable Communication Networks, 2005.","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121263465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-10-16DOI: 10.1109/DRCN.2005.1563856
H. Hinderthür, L. Friedrich
The predominant transmission technology today is still SONET/SDH. Most of the service level agreements service providers have with their customers are based on the characteristics of SONET/SDH protection mechanisms. Therefore significant effort has been spent to transfer the principles of SONET/SDH protection and self healing rings to WDM technology. Mandatory functionality of the protection scheme is protection switching within 50 ms switch-over time, and a permanent monitoring capability for both paths in order to manage switching after path restoration. This leads to DWDM protection schemes like O-UPSR or O-BLSR which are WDM equivalents to the well known UPSR and BLSR schemes from the SONET/SDH world. One major characteristic of those schemes is the protection of the entire end to end path per individual channel. End to end protection in a WDM network means full redundancy in all network sections, i.e. redundant fibre traces and line equipment, redundant filter stages and redundant active WDM channel cards. The switching mechanism takes place either on the application layer or on the tributary side of the channel cards: if the working path fails the protection channel card tributary interface goes active. This means protection is done on the single wavelength level. Looking at service level agreements among numerous service providers it is learned that typical contractually guaranteed availabilities in the metro arena range from 98.000% to 99.990%. O-UPSR or O-BLSR typically outperforms this benchmark at the cost of extremely high capital expenditure (CAPEX). Alternative protection schemes that are characterized by a lower level of redundancy inside the WDM terminals could cut down CAPEX by up to 50%. The logical consequence when reducing the redundancy in a network is an increase of the possible network downtime. Whereas in a path protected WDM terminal channel cards, channel filters and band filter stages are redundant, those alternative protection schemes introduce some sort of path switch in any stage of a WDM terminal such as line, wavelength band, single wavelength or even between line and tributary side of a WDM channel card. Due to this introduction of a single point of failure the probability for service interruption in such an alternatively protected network necessarily increases in some way. But service providers do not leave their network downtime to chance. They are used to plan and design networks according to well defined network availability numbers. The network availability is mainly based on three parameters: Mean time between failure (MTBF) value of transmission equipment, mean time to repair (MTTR) value of transmission equipment, and downtime of fibre per year and kilometer. Based on assumptions that are specific for metro networks the paper gives an overview over different protection schemes for WDM systems. Each protection scheme is explained and characterized by typical configuration, level of redundancy, level of netw
{"title":"Scaling protection to the needs of metro optical networking","authors":"H. Hinderthür, L. Friedrich","doi":"10.1109/DRCN.2005.1563856","DOIUrl":"https://doi.org/10.1109/DRCN.2005.1563856","url":null,"abstract":"The predominant transmission technology today is still SONET/SDH. Most of the service level agreements service providers have with their customers are based on the characteristics of SONET/SDH protection mechanisms. Therefore significant effort has been spent to transfer the principles of SONET/SDH protection and self healing rings to WDM technology. Mandatory functionality of the protection scheme is protection switching within 50 ms switch-over time, and a permanent monitoring capability for both paths in order to manage switching after path restoration. This leads to DWDM protection schemes like O-UPSR or O-BLSR which are WDM equivalents to the well known UPSR and BLSR schemes from the SONET/SDH world. One major characteristic of those schemes is the protection of the entire end to end path per individual channel. End to end protection in a WDM network means full redundancy in all network sections, i.e. redundant fibre traces and line equipment, redundant filter stages and redundant active WDM channel cards. The switching mechanism takes place either on the application layer or on the tributary side of the channel cards: if the working path fails the protection channel card tributary interface goes active. This means protection is done on the single wavelength level. Looking at service level agreements among numerous service providers it is learned that typical contractually guaranteed availabilities in the metro arena range from 98.000% to 99.990%. O-UPSR or O-BLSR typically outperforms this benchmark at the cost of extremely high capital expenditure (CAPEX). Alternative protection schemes that are characterized by a lower level of redundancy inside the WDM terminals could cut down CAPEX by up to 50%. The logical consequence when reducing the redundancy in a network is an increase of the possible network downtime. Whereas in a path protected WDM terminal channel cards, channel filters and band filter stages are redundant, those alternative protection schemes introduce some sort of path switch in any stage of a WDM terminal such as line, wavelength band, single wavelength or even between line and tributary side of a WDM channel card. Due to this introduction of a single point of failure the probability for service interruption in such an alternatively protected network necessarily increases in some way. But service providers do not leave their network downtime to chance. They are used to plan and design networks according to well defined network availability numbers. The network availability is mainly based on three parameters: Mean time between failure (MTBF) value of transmission equipment, mean time to repair (MTTR) value of transmission equipment, and downtime of fibre per year and kilometer. Based on assumptions that are specific for metro networks the paper gives an overview over different protection schemes for WDM systems. Each protection scheme is explained and characterized by typical configuration, level of redundancy, level of netw","PeriodicalId":415896,"journal":{"name":"DRCN 2005). Proceedings.5th International Workshop on Design of Reliable Communication Networks, 2005.","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123256970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-10-16DOI: 10.1109/DRCN.2005.1563899
Ling Zhou, W. Grover
A Service Level Agreement (SLA) is a contract between provider and customer that stipulates certain Quality of Service guarantees. One parameter of an SLA can be the maximum downtime guaranteed over the contract time. If the actual outage exceeds the guarantee, the customer is unhappy and the operator may bear financial penalties. It is important therefore that a network operator not only have some way to estimate or calculate the theoretical long-term availability of the services offered, but some basis for also determining a safety factor on the total outage time promised to a customer on any finite-term contract. As the period gets shorter, either nothing will go wrong and the effective availability will be perfect or if a single outage occurs, the unavailability may seem very bad. More generally, the question is how a network operator can build in theoretically justified safety factors on the availability a customer may experience over a finite-term contract. We are told that most service providers give availability guarantees based empirically on experience and historical statistics. A simple theory is thus proposed to help refine these methods for SLA policy setting. A simulation study is implemented to verify the theory within the axioms it assumes to be true.
{"title":"A theory for setting the \"safety margin\" on availability guarantees in an SLA","authors":"Ling Zhou, W. Grover","doi":"10.1109/DRCN.2005.1563899","DOIUrl":"https://doi.org/10.1109/DRCN.2005.1563899","url":null,"abstract":"A Service Level Agreement (SLA) is a contract between provider and customer that stipulates certain Quality of Service guarantees. One parameter of an SLA can be the maximum downtime guaranteed over the contract time. If the actual outage exceeds the guarantee, the customer is unhappy and the operator may bear financial penalties. It is important therefore that a network operator not only have some way to estimate or calculate the theoretical long-term availability of the services offered, but some basis for also determining a safety factor on the total outage time promised to a customer on any finite-term contract. As the period gets shorter, either nothing will go wrong and the effective availability will be perfect or if a single outage occurs, the unavailability may seem very bad. More generally, the question is how a network operator can build in theoretically justified safety factors on the availability a customer may experience over a finite-term contract. We are told that most service providers give availability guarantees based empirically on experience and historical statistics. A simple theory is thus proposed to help refine these methods for SLA policy setting. A simulation study is implemented to verify the theory within the axioms it assumes to be true.","PeriodicalId":415896,"journal":{"name":"DRCN 2005). Proceedings.5th International Workshop on Design of Reliable Communication Networks, 2005.","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128783076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-07-01DOI: 10.1109/DRCN.2005.1563864
Christian Awad, B. Sansò, A. Girard
In this article, we extend previous work showing that DiffServ can provide some QoS guarantees to both realtime and non real-time traffic in the event of the failure of an optical component. Even though DiffServ cannot totally replace optical protection in a network, it might be able to do so to some degree. In this paper, we study a 4-node linear topology which can be protected by DiffServ, DiffProtect or even a combination of both (MixProtect). We evaluate the performance of all protection combinations which enables us to study the extent to which we could replace optical protection by DiffServ in a particular network. Results have shown that replacing optical protection by DiffServ cannot be done randomly, the number and positions of DiffServ protected links versus DiffProtect's must be carefully chosen in order to guarantee maximum performance to all traffic types.
{"title":"Network reliability under mixed IP and optical protection","authors":"Christian Awad, B. Sansò, A. Girard","doi":"10.1109/DRCN.2005.1563864","DOIUrl":"https://doi.org/10.1109/DRCN.2005.1563864","url":null,"abstract":"In this article, we extend previous work showing that DiffServ can provide some QoS guarantees to both realtime and non real-time traffic in the event of the failure of an optical component. Even though DiffServ cannot totally replace optical protection in a network, it might be able to do so to some degree. In this paper, we study a 4-node linear topology which can be protected by DiffServ, DiffProtect or even a combination of both (MixProtect). We evaluate the performance of all protection combinations which enables us to study the extent to which we could replace optical protection by DiffServ in a particular network. Results have shown that replacing optical protection by DiffServ cannot be done randomly, the number and positions of DiffServ protected links versus DiffProtect's must be carefully chosen in order to guarantee maximum performance to all traffic types.","PeriodicalId":415896,"journal":{"name":"DRCN 2005). Proceedings.5th International Workshop on Design of Reliable Communication Networks, 2005.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125575010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-06-13DOI: 10.1109/NETWKS.2004.240682
T. Hubbard
The premise of this paper is based on the simple marketing concept that work should be an activity not a location, it is something people do and not somewhere they go. This simple marketing concept has been enabled by the availability of new technology, new applications, and new services from an array of vendors and service providers. These technologies, applications, and services include: secure connectivity using SSL, IPSec, and MPLS based IP VPNs; high speed broadband access using Wi-Fi, xDSL, and UMTS; applications including telephony, video, email, and Internet services can run on laptops, personal data assistants (PDAs), and smartphones; the separation of network and service following the introduction of telephony and video call servers; and devices can be secured and protected using personal firewalls, intrusion detection, anti virus, and bio-metric access. By bringing together all this technology as a service offering, enterprises are able to securely extend their corporate IT infrastructures and applications to locations, remote workers, and home workers irrespective of where they happen to be. This paper looked at how these technologies can be brought together to make work an activity not a location.
{"title":"Enabling flexible working using hybrid IP VPNs","authors":"T. Hubbard","doi":"10.1109/NETWKS.2004.240682","DOIUrl":"https://doi.org/10.1109/NETWKS.2004.240682","url":null,"abstract":"The premise of this paper is based on the simple marketing concept that work should be an activity not a location, it is something people do and not somewhere they go. This simple marketing concept has been enabled by the availability of new technology, new applications, and new services from an array of vendors and service providers. These technologies, applications, and services include: secure connectivity using SSL, IPSec, and MPLS based IP VPNs; high speed broadband access using Wi-Fi, xDSL, and UMTS; applications including telephony, video, email, and Internet services can run on laptops, personal data assistants (PDAs), and smartphones; the separation of network and service following the introduction of telephony and video call servers; and devices can be secured and protected using personal firewalls, intrusion detection, anti virus, and bio-metric access. By bringing together all this technology as a service offering, enterprises are able to securely extend their corporate IT infrastructures and applications to locations, remote workers, and home workers irrespective of where they happen to be. This paper looked at how these technologies can be brought together to make work an activity not a location.","PeriodicalId":415896,"journal":{"name":"DRCN 2005). Proceedings.5th International Workshop on Design of Reliable Communication Networks, 2005.","volume":"38 13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133374923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：