Có 60+ tài liệu thuộc chủ đề "kiến trúc mạng quang"
tailieu.vn Xem trực tuyến Tải xuống
Client Layers of the Optical Layer. These networks can be thought of as client layers of the optical layer. As we saw in Chapter 1, the optical layer provides lightpaths to the client layers. All the client layers that we will study process the data in the electrical domain, performing functions such as fixed time division multiplexing or statistical time...
tailieu.vn Xem trực tuyến Tải xuống
While SDH employs the same philosophy as SONET, there are some differ- ences in terminology and in the multiplexing structure for sub-STM-1 signals.. The functions of these layers will become clearer when we discuss the frame structure and overheads associated with each layer in the next section.. It is possible that intermediate nodes may do performance monitoring of the path...
tailieu.vn Xem trực tuyến Tải xuống
380 CLIENT LAYERS OF THE OPTICAL LAYER. In general, UPSRs are used in the access part of the network to connect multiple nodes to a hub node residing in a central office, and BLSRs are used in the interoffice part of the network to interconnect multiple central offices.. Another major component in the SONET infrastructure is a digital crossconnect (DCS)....
tailieu.vn Xem trực tuyến Tải xuống
IP was one of the earliest packet-switching protocols. IP transports information in the form of packets, which are of variable length. The routing table has one or more entries for each destination router in the network. The header contains the identity of the destination router for that packet. The router then does a lookup of its routing table to determine...
tailieu.vn Xem trực tuyến Tải xuống
400 CLIENT LAYERS OF THE OPTICAL LAYER. (b) Many SONET streams are to be multiplexed onto a higher-speed stream and transmitted over a SONET link.. (c) A fiber fails and SONET line terminals at the end of the link reroute all the traffic on the failed fiber onto another fiber.. (d) The error rate on a SONET link between regenerators...
tailieu.vn Xem trực tuyến Tải xuống
These transponders constitute a significant portion of the system cost.. Consider what is needed at node B. Therefore, six out of the eight transponders at node B are used to handle passthrough traffic--a very expensive proposition.. Consider the OADM solution shown in Figure 7.4(b). The network uses an OLT at nodes A and C and an OADM at node B....
tailieu.vn Xem trực tuyến Tải xuống
Figure 7.8 Using an OXC in the network. The OXC sits between the client equipment of the optical layer and the optical layer OLTs.. This capability becomes important when we deal with large numbers of wavelengths in a node or with a large number of nodes in the network. It also becomes important when the lightpaths in the network need...
tailieu.vn Xem trực tuyến Tải xuống
We also looked at reconfigurable OADM architectures, which use tunable filters and/or multiplexers, as well as tunable lasers, in order to provide the maximum possible flexibility in the network.. An optical crossconnect (OXC) is the other key network element in the optical layer. As with OADMs, several variants of OXCs exist, ranging from OXCs with electrical switch cores capable of...
tailieu.vn Xem trực tuyến Tải xuống
Figure 8.2 (a) The lightpath topology of the three-node network corresponding to Figure 8.1(a) that is seen by the routers. (b) The lightpath topology of the three-node network corresponding to Figure 8.1(b) that is seen by the routers. The task is to design a lightpath topology that interconnects the IP routers and to realize this topology within the optical layer....
tailieu.vn Xem trực tuyến Tải xuống
The solution to the lightpath topology design problem will specify which of the bij a r e 1 and which are 0. This is not a problem if the traffic is IP packets, but if we were instead considering SONET circuits, this is tantamount to assuming that the traffic between nodes consists of a large number of such circuits. Let...
tailieu.vn Xem trực tuyến Tải xuống
Figure 8.13 An example to illustrate the difference between having and not having wavelength conversion.. However, without wavelength conversion, the number of wavelengths required could be much larger. Example 8.6 Consider the network shown in Figure 8.13. The set of lightpath requests is shown in the figure to be the following. Transmitter ti must be con- nected to receiver r...
tailieu.vn Xem trực tuyến Tải xuống
Figure 8.18 Reuse factor plotted against the number of nodes for random graphs with average degree 4, with full wavelength conversion and no wavelength conversion (from [RS95]).. converters, the wavelength assignment algorithm assigns an arbitrary free wave- length on every link in the route to the lightpath. thus we assume full wavelength conversion. In both cases, if the wavelength assignment...
tailieu.vn Xem trực tuyến Tải xuống
480 W D M NETWORK DESIGN. Table 8.4 Number of wavelengths required to perform offline wavelength assign- ment as a function of the load L with and without wavelength converters. Other topologies such as star networks and tree networks have also been consid- ered in the literature. The same result can be extended to arbitrary networks where lightpaths are at...
tailieu.vn Xem trực tuyến Tải xuống
IEEE Transactions on Communications,. Topologies for high-speed optical networks. Heuristic algorithms for joint configuration of the optical and electrical layer in multi-hop wavelength routing networks. In Proceedings of IEEE Infocom, 2000.. Dynamic wavelengh allocation in all-optical ring networks. In Proceedings of IEEE International Conference on Communication, 1997.. In Proceedings of IEEE Infocom, 1999.. In Proceedings of IEEE Infocom, 1998.. Worst-case...
tailieu.vn Xem trực tuyến Tải xuống
Multiple types of shelves may be represented in the form of inherited object classes from the parent object shelf. Multiple types of line cards may be represented in the form of inherited object classes from the parent object line card. Each object has a variety of attributes associated with it, including the set of parameters that can be set by...
tailieu.vn Xem trực tuyến Tải xuống
In a network, a single failure event may cause multiple alarms to be generated all over the network and incorrect actions to be taken in response to the failed condition.. This could be detected at the nodes at the end of the failed link, which would then issue alarms for each individual lightpath as well as report an entire link...
tailieu.vn Xem trực tuyến Tải xuống
able to add additional wavelengths (up to a designed maximum number) without disrupting the operation of the existing wavelengths. Using arrayed components can reduce the cost and footprint of the equipment. However, if one element in the array fails, the entire array will have to be replaced. Using arrays also increases the replacement cost of the module. We may also...
tailieu.vn Xem trực tuyến Tải xuống
Operating costs dominate equipment costs for most telecom networks, making good network management imperative in ensuring the smooth operation of the network. It is useful to break down the optical layer into three sublayers: the optical channel layer, which deals with individual connections or lightpaths and is end to end across the network. the optical multiplex section layer, which deals...
tailieu.vn Xem trực tuyến Tải xuống
SONET/SDH. In the optical layer, many protection schemes have been designed to operate over true mesh topologies.. In dedicated protection, each working connection is assigned its own dedicated bandwidth in the network over which it can be rerouted in case of a failure. In shared protection, we make use of the fact that not all working connections in the network...
tailieu.vn Xem trực tuyến Tải xuống
It is simple to implement and requires no signaling protocol or communication between the nodes. This will turn out to be the case for the other ring architectures as well.. This is because each (bidirectional) connection uses up capacity on every link in the ring and has dedicated protection bandwidth associated with it. Thus, there is no sharing of the...