3Com 3C63311 Reference Guide - Page 16

4 CHAPTER 1: SYSTEM DESCRIPTION n Choice of either single-mode or multi-mode OC3/STM-1 (separate units), through the OC3/STM-1 module. Single-mode enables higher-speed trunking if you have access to fiber WAN, while multi-mode is ideal for connecting high-speed servers, switches, or hubs equipped with multi-mode fiber connections. n Three expansion slots, allowing you to add other advanced features, such as T1-DSX or E1 CBR for voice and video, voice compression, or DS3/E3. n 4x switch switching architecture, including four priority queues (three queues shaped and one bulk shaper) with user-defined queue sizes and early and partial packet discard capability. n Device management via VT100 menu-driven interface, Telnet, or SNMP, with local, remote, and in-band access. The following optional modules are available for use with the PathBuilder S330: n The four-port CBR module services traffic generated by your existing PBXs, channels, T1/E1 multiplexers, CSU/DSUs, and video conferencing devices. The CBR module consists of one V.35/RS-449 and three T1-DSX or E1 interfaces, which support both structured and unstructured services, in accordance with the ATM Forum's Circuit Emulation Service (CES) specifications. The CBR module provides a smooth migration from legacy CBR service (PBX/voice/video) to ATM service. It also supports all relevant ATM and T1/E1 standards, ensuring easy integration of existing equipment into new ATM networks. n The one-port Voice Compression module (VCM) is similar in function to the CBR module, but it employs compression algorithms that allow more voice calls to be placed through the same bandwidth. The VCM's T1-DSX/E1 interface connects to a PBX trunk, which may use CAS or CCS signaling. Its 24/31 DSO channels can carry individual voice, fax, modem, or data connections. You can also bundle multiple DSOs to provide connections for high-rate applications such as video conference or multiple-link PPP. For CCS, a DSO is used as an ISDN D-channel for carrying signal messages. n The DS3/E3 module provides a DS3 or E3 interface, typically used for terminating/accessing the public or private ATM WAN services. However, depending on your local applications, you can also use these modules for taking local DS3 or E3 ATM traffic across the WAN. Figure 1 shows the PathBuilder S330 with the optional CBR module installed in expansion slot 7, Voice Compression module in slot 8, and DS3/E3 UNI module in slot 9.