CCNP Routing Study Guide- P19:T his book is intended to help you continue on your exciting new path toward obtaining your CCNP and CCIE certification. Before reading this book, it is important to have at least read the Sybex CCNA: Cisco Certified Network Associate Study Guide, Second Edition. You can take the CCNP tests in any order, but you should have passed the CCNA exam before pursuing your CCNP. | Glossary 509 switch block The switch block is a combination of Layer 3 switches and Layer 3 routers. The Layer 2 switches connect users in the wiring closet into the Access layer and provide 10 or 100Mbps dedicated connections. 1900 2820 and 2900 Catalyst switches can be used in the switch block. switched Ethernet Device that switches Ethernet frames between segments by filtering on hardware addresses. switched LAN Any LAN implemented using LAN switches. See also LAN switch. switch-fabric The central functional block of any switch design responsible for buffering and routing the incoming data to the appropriate output ports. synchronous transmission Signals transmitted digitally with precision clocking. These signals have identical frequencies and contain individual characters encapsulated in control bits called start stop bits that designate the beginning and ending of each character. See also asynchronous transmission and isochronous transmission. T reference point Used with an S reference point to change a 4-wire ISDN network to a 2-wire ISDN network. T1 Digital WAN that uses 24 DS0s at 64K each to create a bandwidth of minus clocking overhead providing of usable bandwidth. T3 Digital WAN that can provide bandwidth of . TACACS Terminal Access Control Access Control System An enhanced version of TACACS this protocol is similar to RADIUS. See also RADIUS. tag switching Based on the concept of label swapping where packets or cells are designated to defined-length labels that control the manner in which data is to be sent tag switching is a high-performance technology used for forwarding packets. It incorporates Data Link layer Layer 2 switching and Network layer Layer 3 routing and supplies scalable high-speed switching in the network core. Copyright 2001 SYBEX Inc. Alameda CA 510 Glossary tagged traffic ATM cells with their cell loss priority CLP bit set to 1. Also referred to as discard-eligible DE traffic. Tagged .
