direkt zum Inhalt springen

direkt zum Hauptnavigationsmenü

Sie sind hier

TU Berlin

Inhalt des Dokuments

Past talks, student talks, and other events of 2013

Tuesday, 19. November 2013

Socket Intents: Leveraging Application Awareness for Multi-Access Connectivity
Speaker:
Philipp Schmidt
Type:
PGT talk
Time:
19 November 2013
16:00–17:00
Place:
FH 316
Abstract:
In today’s Internet, almost all end devices have multiple interfaces built in. This enables users to seamlessly switch between different access networks or even use them simultaneously; to better use the resources available to them and to better satisfy their needs. This is referred to as mobile data offloading and has received lots of atten- tion recently in both the research community and in the industry. However, all the proposed data solutions either rely on static con- figuration policies or are reactive rather than proactive with regards to the application needs. In this paper, we propose a proactive, application informed ap- proach, Socket Intents. Socket Intents augment the socket interface to enable the application to express what it knows about its communication patterns and preferences. This information can then be used by our proactive policies to choose the appropriate interface, tune the network parameters, or even combine multiple interfaces. We provide a prototype implementation of our Socket Intents and present a first evaluation of the Intents and its benefits.

Tuesday, 17. September 2013

Virtual Network Embedding with Collocation: Benefits and Limitations of Pre-Clustering
Speaker:
Carlo Fürst
Type:
PGT Talk
Time:
17 September 2013
15:00–16:00
Place:
Auditorium 1, TEL 20
Abstract:
Given that mechanisms for resource isolation are in place, the collocation of virtual network (VNet) nodes is attractive as it reduces the inter-machine communication and hence improves the VNet embedding. However, existing VNet embedding algorithms either do not support the collocation of virtual nodes of the same VNet, or only support it implicitly by referring to the possibility to pre-cluster the VNet topology: this pre-clustered network forms the new VNet request and is embedded accordingly. This talk presents a pre-clustering algorithm OPT CUT that is optimal in the sense that it minimizes the amount of link resources needed for the embedding. It is based on a smart linear program formulation that ensures fast solutions. OPT CUT can be used together with any existing VNet embedding algorithms, and we show that it can greatly improve the state-of-the-art embedding algorithm SecondNet. The talk also describes a simple algorithm LOCO that directly supports collocation. This algorithm is part of a novel and generic VNet embedding framework METATREE which may be of independent interest. We compare the performance of the pre-clustering approaches with the direct VNet embeddings by LOCO, and find that pre-clustering also has its limitations. In particular, the information gap between the pre-clustering and the actual algorithm, as well as an inaccurate estimation of the distribution of remaining substrate resources, may lead to a low network utilization.

Tuesday, 06. August 2013

Software Transactional Networking: Concurrent, Consistent Network Policy Composition
Speaker:
Daniel Levin
Type:
Talk
Time:
06 August 2013
15:00–16:00
Place:
Auditorium 1, TEL 20
Abstract:
It seems natural to imagine that SDN policy specification and control is distributed, and this paper focuses on the resulting concurrency issues. Indeed, conflicts among concurrent policy updates may result in serious inconsistencies on the data plane, even when each update is installed with per-packet consistent update semantics. This paper introduces the problem of consistent composition of concurrent policy updates. Intuitively, consistent concurrent policy composition must appear as though there is no concurrency neither between any policy updates, nor between a policy update and in-flight packets on the data plane. We propose an elegant policy composition abstraction based on a transactional interface with all-or-nothing semantics: a policy update is either committed, in which case the policy is guaranteed to compose consistently over the entire network and the update is installed in its entirety, or aborted, in which case, no packet is affected by it. Consequently, the control application logic is relieved from the cumbersome and potentially error-prone synchronization and locking tasks, and control applications are kept light-weight. In this paper, we also sketch a simple implementation of the transactional synchronization: our approach is based on fine-grained locking on network components and avoids complex state machine replication.

Tuesday, 18. June 2013

On the Importance of IXPs for today's Internet and some research topics
Speaker:
Nikolaos Chatzis (TU Berlin)
Type:
PGT talk
Time:
18 June 2013
15:00–16:00
Place:
Auditorium 1, TEL 20
Abstract:
The number of operational Internet eXchange Points (IXPs) worldwide has grown to some 400, with the largest IXPs handling daily traffic volumes comparable to those carried by the largest Tier-1 ISPs. Despite this fact, IXPs have never really attracted any attention from the networking research community. At first glance, this lack of interest seems understandable as IXPs have apparently little to do with current “hot” topic areas such as data centers and cloud services or software defined networking (SDN) and mobile communication. The goal of this talk is to present some aspects concerning the architecture, operations, and service offerings of IXPs, report on past and ongoing measurement-based research around IXPs, and showcase IXPs as a rich source for interesting networking research problems.

Zusatzinformationen / Extras

Quick Access:

Schnellnavigation zur Seite über Nummerneingabe

Auxiliary Functions