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Multiple Spanning Tree Protocol
The Multiple Spanning Tree Protocol (MSTP) and algorithm, provides both simple and full connectivity assigned to any given Virtual LAN (VLAN) throughout a Bridged Local Area Network. MSTP uses BPDUs to exchange information between spanning-tree compatible devices, to prevent loops in each MSTI (Multiple Spanning Tree Instances) and in the CIST (Common and Internal Spanning Tree), by selecting active and blocked paths. This is done as well as in STP without the need of manually enabling backup links and getting rid of switching loop danger. Moreover, MSTP allows frames/packets assigned to different VLANs to follow separate paths, each based on an independent MSTI, within MST Regions composed of LANs and or MST Bridges. These Regions and the other Bridges and LANs are connected into a single Common Spanning Tree (CST). History and motivation It was originally defined in IEEE 802.1s as an amendment to 802.1Q, 1998 edition and later merged into IEEE 802.1Q-2005 Standard, clea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. More advanced algorithms can perform automated deductions (referred to as automated reasoning) and use mathematical and logical tests to divert the code execution through various routes (referred to as automated decision-making). Using human characteristics as descriptors of machines in metaphorical ways was already practiced by Alan Turing with terms such as "memory", "search" and "stimulus". In contrast, a Heuristic (computer science), heuristic is an approach to problem solving that may not be fully specified or may not guarantee correct or optimal results, especially in problem domains where there is no well-defined correct or optimal result. As an effective method, an algorithm ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port (computer Networking)
In computer networking, a port is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system, a port is a logical construct that identifies a specific process or a type of network service. A port is identified for each transport protocol and address combination by a 16-bit unsigned number, known as the port number. The most common transport protocols that use port numbers are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). A port number is always associated with an IP address of a host and the type of transport protocol used for communication. It completes the destination or origination network address of a message. Specific port numbers are reserved to identify specific services so that an arriving packet can be easily forwarded to a running application. For this purpose, port numbers lower than 1024 identify the historically most commonly used services ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unidirectional Link Detection
Unidirectional Link Detection (UDLD) is a data link layer protocol from Cisco Systems to monitor the physical configuration of the cables and detect unidirectional links. UDLD complements the Spanning Tree Protocol which is used to eliminate switching loops. :* Unidirectional Link Detection (UDLD) is one of two major features (UDLD and loop guard) in Cisco Switches to prevent Layer 2 loops. :* Spanning-Tree Protocol (STP) resolves redundant physical topology into a loop-free, tree-like forwarding topology via blocking one or more ports. : However, Unidirectional Link failure can cause " traffic blackholing" and loops in the Switch topology. :* In order to detect the unidirectional links before the forwarding loop is created, UDLD works by exchanging protocol packets between the neighboring devices. :* In order for UDLD to work, both switch devices on the link must support UDLD and have it enabled on respective ports. Description If two devices, A and B, are connected via a pai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRILL (computing)
TRILL (Transparent Interconnection of Lots of Links) is an Internet Standard implemented by devices called TRILL switches. TRILL combines techniques from bridging and routing, and is the application of link-state routing to the VLAN-aware customer-bridging problem. Routing bridges (RBridges) are compatible with and can incrementally replace previous IEEE 802.1 customer bridges. TRILL Switches are also compatible with IPv4 and IPv6, routers and end systems. They are invisible to current IP routers, and like conventional routers, RBridges terminate the broadcast, unknown-unicast and multicast traffic of DIX Ethernet and the frames of IEEE 802.2 LLC including the bridge protocol data units of the Spanning Tree Protocol. TRILL is the successor to Spanning Tree Protocol, both having been created by the same person, Radia Perlman. The catalyst for TRILL was an event at Beth Israel Deaconess Medical Center which began on 13 November 2002. The concept of Rbridges icwas first proposed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Spanning Tree
A minimum spanning tree (MST) or minimum weight spanning tree is a subset of the edges of a connected, edge-weighted undirected graph that connects all the vertices together, without any cycles and with the minimum possible total edge weight. That is, it is a spanning tree whose sum of edge weights is as small as possible. More generally, any edge-weighted undirected graph (not necessarily connected) has a minimum spanning forest, which is a union of the minimum spanning trees for its connected components. There are many use cases for minimum spanning trees. One example is a telecommunications company trying to lay cable in a new neighborhood. If it is constrained to bury the cable only along certain paths (e.g. roads), then there would be a graph containing the points (e.g. houses) connected by those paths. Some of the paths might be more expensive, because they are longer, or require the cable to be buried deeper; these paths would be represented by edges with larger weights ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Media Redundancy Protocol
Media Redundancy Protocol (MRP) is a data network protocol standardized by the International Electrotechnical Commission as IEC 62439-2. It allows rings of Ethernet switches to overcome any single failure with recovery time much faster than achievable with Spanning Tree Protocol. It is suitable to most industrial Ethernet applications. Properties MRP operates at the data link layer (OSI Layer 2) of Ethernet switches and is a direct evolution of the HiPER-Ring protocol developed by Hirschmann in 1998. Hirschmann is now owned by Belden. MRP is supported by several commercial industrial Ethernet switches. In an MRP ring, the ring manager is named Media Redundancy Manager (MRM), while ring clients are named Media Redundancy Clients (MRCs). MRM and MRC ring ports support three statuses: disabled, blocked, and forwarding. Disabled ring ports drop all the received frames. Blocked ring ports drop all the received frames except the MRP control frames. Forwarding ring ports forward a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flex Links
Flex links is a network switch feature in Cisco equipment which enables redundancy and load balancing at the layer 2 level. The feature serves as an alternative to Spanning Tree Protocol or link aggregation. A pair of layer 2 interfaces, such as switch ports or port channels has one interface configured as a backup to the other. If the primary link fails, the backup link takes over traffic forwarding. At any point of time only one interface will be in linkup state and actively forwarding traffic. If the primary link shuts down, the standby link takes up the duty and starts forwarding traffic and becomes the primary link. When the failing link comes back up active, it goes into standby mode and does not participate in traffic forwarding and becomes the backup link. This behaviour can be changed with pre-emption mode which makes the failed link the primary link when it becomes available again. Load balancing in Flex links work at VLAN A virtual local area network (VLAN) is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethernet Automatic Protection Switching
Ethernet Automatic Protection Switching (EAPS) is used to create a fault tolerant topology by configuring a primary and secondary path for each VLAN. Invented by Extreme Networks and submitted to IETF as RFC3619. The idea is to provide highly available Ethernet switched rings (commonly used in Metro Ethernet) to replace legacy TDM based transport protection fiber rings. Other implementations include Ethernet Protection Switching Ring (EPSR) by Allied Telesis which enhanced EAPS to provide full protected transport of IP Triple Play services (voice, video and internet traffic) for xDSL/FTTx deployments. EAPS/EPSR is the most widely deployed Ethernet protection switching solution deployed with major multi-vendor inter-operability support. The EAPS/EPSR are the basis of the ITU G.8032 Ethernet Protection recommendation. Operation A ring is formed by configuring a Domain. Each domain has a single "master node" and many "transit nodes". Each node will have a primary port and a seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EtherChannel
EtherChannel is a port link aggregation technology or port-channel architecture used primarily on Cisco switches. It allows grouping of several physical Ethernet links to create one logical Ethernet link for the purpose of providing fault-tolerance and high-speed links between switches, routers and servers. An EtherChannel can be created from between two and eight active Fast, Gigabit or 10-Gigabit Ethernet ports, with an additional one to eight inactive (failover) ports which become active as the other active ports fail. EtherChannel is primarily used in the backbone network, but can also be used to connect end user machines. EtherChannel technology was invented by Kalpana in the early 1990s. Kalpana was acquired by Cisco Systems in 1994. In 2000, the IEEE passed 802.3ad, which is an open standard version of EtherChannel. Benefits Using an EtherChannel has numerous advantages, and probably the most desirable aspect is the bandwidth. Using the maximum of 8 active ports a total ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Minimum Spanning Tree
The distributed minimum spanning tree (MST) problem involves the construction of a minimum spanning tree by a distributed algorithm, in a network where nodes communicate by message passing. It is radically different from the classical sequential problem, although the most basic approach resembles Borůvka's algorithm. One important application of this problem is to find a tree that can be used for broadcasting. In particular, if the cost for a message to pass through an edge in a graph is significant, an MST can minimize the total cost for a source process to communicate with all the other processes in the network. The problem was first suggested and solved in O(V \log V) time in 1983 by Gallager ''et al.'', where V is the number of vertices in the graph. Later, the solution was improved to O(V) and finally O(\sqrt V \log^* V + D) where ''D'' is the network, or graph diameter. A lower bound on the time complexity of the solution has been eventually shown to beDavid Peleg and Vitaly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Address Resolution Protocol
The Address Resolution Protocol (ARP) is a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address. This mapping is a critical function in the Internet protocol suite. ARP was defined in 1982 by , which is Internet Standard STD 37. ARP has been implemented with many combinations of network and data link layer technologies, such as IPv4, Chaosnet, DECnet and Xerox PARC Universal Packet (PUP) using IEEE 802 standards, FDDI, X.25, Frame Relay and Asynchronous Transfer Mode (ATM). In Internet Protocol Version 6 (IPv6) networks, the functionality of ARP is provided by the Neighbor Discovery Protocol (NDP). Operating scope The Address Resolution Protocol is a request-response protocol. Its messages are directly encapsulated by a link layer protocol. It is communicated within the boundaries of a single network, never routed across internetworking nodes. Packet structure The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
