tailieunhanh - mcgraw hill wireless data demystified phần 8

liên kết cho phép tích hợp băng thông rộng mạng xương sống và các dịch vụ kết hợp thông qua một cơ sở hạ tầng được chia sẻ duy nhất, dẫn đến việc triển khai nhanh hơn và hệ thống chi phí thấp hơn cho các nhà cung cấp dịch vụ. | Chapter 16 Packet-over-SONET SDH Specification 391 Figure 16-5 A DOS node ISP a an example of network architecture using DOS 6 functional architecture c hardware architecture. TDM bandwidth DOS node DOS node DOS node Private network Data services - Flexible and efficient bandwidth application Shared bandwidth . STS-3c-10v Private network node DOS node a Metro access network Main frame PKTSW GFP Generic Framing Procedure TGFP Transparent gFp SONET SDH Next-generation SONET SDH Path switching PsW f Virtual 1 Concatenation FICON L-ESCONj LCAS LCAS Link Capacity Adjustment Scheme b sense that the latter is focused on wireless data transport only Ethernet directly over fiber is currently the interface of choice for metro-area applications. In contrast besides wireless data applications the hybrid services support TDM applications as well and can be used in both MAN and WAN scenarios. NOTE The channel identifier field in GFP linear frame structure can be used to distinguish 256 data streams within a single SONET SDH path see Fig. 16-6 .3 392 Part 3 Installing and Deploying Data Networks Figure 16-5 Continued Tributary Transport node Aggregate c Figure 16-6 The GFP linear frame Payload header structure. 4B 2B 2B 1B 1B 2B 4B Figure 16-5 shows a typical functional architecture of a DoS node. The node provides transport interfaces such as legacy SONET SDH ESCON FICON and GbE for a wide range of applications. The DoS node uses virtual concatenation and GFP as enablers to efficiently pack wireless application data into SONET SDH frames. It also uses LCAS to regulate the amount of bandwidth assigned to transport the client wireless data. DoS nodes are designed to provide a wide variety of line interfaces so that new services can be launched without deployment of new nodes. Chapter 16 Packet-over-SONET SDH Specification 393 New line interface cards are installed as need arises. Interfaces for a data center ESCON FICON Fibre Channel and digital video DVB-ASI are also utilized.