Tesis doctoral de Luis Fernando Caro Perez
Due to recent advances, ethernet is starting to move from local area networks to carrier networks. Nevertheless as the requirements of carrier networks are more demanding, the technology needs to be enhanced. Schemes designed for improving ethernet to match carrier requirements can be categorized in two classes. The first class improves ethernet control components only, and the second class improves both ethernet control and forwarding components. the first class rely only on improving ethernet control components such as multiple spanning tree protocol (mstp) and rapid spanning tree protocol (rstp). With mstp, several spanning trees can be created in the same ethernet network, allowing to route traffic through different paths between a pair of nodes in the network. These technologies use this property to perform traffic engineering as well as to support protection by reserving resources to be used in case of network failure. the second class relies on improving both ethernet control and forwarding components. These techniques change the ethernet forwarding plane by implementing forwarding based on an identifier, referred to as a label, defined by a subset of the ethernet medium access control frame header fields. Packets are sent through specific sequences of nodes denominated label switched paths (lsp), giving similar functionality to that of multi-protocol label switching (mpls). For this purpose each packet is marked with a label identifying the lsp through which it is sent. Each node uses the label as the index to look up in the forwarding table both the node where the packet needs to be forwarded to and the new label used to identify the packet in the next node. Two technologies under this class are considered in this document: ethernet vlan-label switching (els) and provider backbone bridges – traffic engineering (pbb-te). both els and pbb-te use a different label size and scope than previous label based technologies such as mpls (20 bits allowing up to 1048576 lsp per interface), in addition to not allowing to stack labels. For this reason, this thesis analyzes and compares label space usage for both architectures to ensure their scalability. The applicability of existing techniques and studies that can be used to overcome or reduce label scalability issues is evaluated for both els and pbb-te. For els, a new routing algorithm to improve els label space usage is proposed. For pbb-te, the label reutilization technique is formalized. additionally, none of the previous studies on label space usage in any of the existing label based forwarding architectures (e.G. Mpls) analyzes the impact of the topology characteristics on label space usage. Consequently, this thesis studies how topology characteristics affect the different label scopes. Both the number of states and the number of labels needed (relevant for label exhaustion) considering label per link (used by els and mpls) and destination scopes (used by pbb-te) are analyzed. finally, despite all the studies that have been performed for the class of approaches improving spanning tree protocols, they are always compared either among themselves or against the use of basic native ethernet protocols. Additionally there is not any study that can determine when label based forwarding technologies have to be used instead of stp based approaches. Therefore, this thesis proposes an ilp to calculate optimal performance of this class of approaches and compares them with label based forwarding technologies to be able to determine, given a specific scenario, which approach to use.
Datos académicos de la tesis doctoral «Improving resource utilization in carrier ethernet technologies«
- Título de la tesis: Improving resource utilization in carrier ethernet technologies
- Autor: Luis Fernando Caro Perez
- Universidad: Girona
- Fecha de lectura de la tesis: 19/01/2010
Dirección y tribunal
- Director de la tesis
- José Luis Marzo Lazaro
- Tribunal
- Presidente del tribunal: eusebi Calle ortega
- davide Careglio (vocal)
- Fernando Solano donado (vocal)
- sarah Ruepp (vocal)