Networking Concepts Lesson 11 - Enterprise & Distributed Networks - Eric Vanderburg
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This document discusses networking concepts related to expanding networks, modems, digital modems, carriers, remote access services (RRAS), virtual private networks (VPN), virtual local area networks (VLAN), routing, brouters, and gateways. Key points include the evolution of modem standards to support higher speeds, differences between asynchronous and synchronous communication, digital modem technologies like ISDN and DSL, remote access protocols like PPP, and VPNs as a more secure and cost-effective alternative to modem pools.
Networking Concepts Lesson 11 - Enterprise & Distributed Networks - Eric Vanderburg
- 1. Chapter 11 Enterprise & Distributed Networks Networking Concepts – Eric Vanderburg ©2005
- 2. Expanding Networks Modem (Modulator/Demodulator) RJ11 phone port External modems use RS-232 (Recommended Standard 232) serial port Hayes-compatible – works with software designed for the original Hayes modems in the early 80’s Networking Concepts – Eric Vanderburg ©2005
- 3. Modems Baud – number of sound wave oscillations per second – old modems transferred 1 bit/baud ITU (International Telecommunications Union) – created the V-series standards • • • • • V.22bis* – 2400baud, 2.4kbps V.32 – 2400baud, 9.6kbps V.32bis – 2400baud, 13.4kbps V.32ter – 2400baud, 19.2kbps V.FC (Fast Class) – 9600baud, 28.8kbps • • • • • V.34 – 9600baud, 28.8kbps V.34bis – 9600baud, 33.6kbps V.42bis – uses compression & error correction, 28.8kbps V.90 – 56k d/l, 22.6k u/l V.92 – modem on hold, 56k Networking respectively *Bis & ter mean 2nd & 3rd revisionsConcepts – Eric Vanderburg ©2005
- 4. Modems Asynchronous – start and stop bits are placed before and after each byte (8 bits + parity bit). More check data and more overhead. PCM (Pulse Code Modulation) – digitizing an analog signal on a modem 33.6 Kbps from modem to ISP 56 Kbps from ISP to modem MNP Class 5 compression Synchronous – devices agree on a timing scheme utilizing sync bits and transfer blocks of data (frames) accordingly. Less overhead, leased line use. Also provide error checking. SDLC (Synchronous Data Link Control) HDLC (High-level Data Link Control) Bisync (Binary Synchronous) Transfer rates depend on Line conditions V standard FCC regulations (max is 54kbps) Networking Concepts – Eric Vanderburg ©2005
- 5. Digital Modems ISDN (Integrated Services Digital Network) Cable NT (Network Termination) TA (Terminal Adapter) BRI (Basic Rate Interface) – 2 B channels (64k) & 1 D channel (16k), $50-$70 PRI (Primary Rate Interface) – 23 B channels, 1 D channel (H10=1472 kb/s *see ch.7), $300-$1500 DOCSIS encrypts each connection to increase security. DSL Distance limitation between user and CO (17,500-23,000ft) ADSL (Asymmetric Digital Subscriber Line) - 8 Mbps d/l, 1 Mbps u/l SDSL (Symmetric Digital Subscriber Line) - equal d/l and u/l speeds Networking Concepts – Eric Vanderburg ©2005
- 6. Carriers Throughput – how much data can be sent over the line per second Distance Cost Networking Concepts – Eric Vanderburg ©2005
- 7. RRAS RRAS Authentication Wizard Networking Concepts – Eric Vanderburg ©2005
- 8. RRAS & terms RRAS DUN (Dial-up Networking) SLIP (Serial Line Internet Protocol) Layer 1 Works with TCP/IP only CSLIP (Compressed Serial Line Internet Protocol) Max concurrent clients: 256 Called RAS (Remote Access Service) in NT Same as SLIP but can compress data to increase speed PPP (Point-to-Point Protocol) Layers 1 & 2 Works with IP, IPX, & NetBEUI Can compress & check for errors Supports DHCP Networking Concepts – Eric Vanderburg ©2005
- 9. Other Vendors Novell NetWare provides VPN server connections Able to form VPN WAN by connecting corporate LANs over VPN connections through the Internet Mac OS version 9 and above support VPN client connections to Windows servers using PPTP or IPSec Mac OS X Server provides a VPN server service that permits Mac OS, Windows, and Linux/Unix clients to connect to the corporate LAN Linux versions using L2TP may not be compatible with Windows VPN solutions Networking Concepts – Eric Vanderburg ©2005
- 10. VPN Linux supports VPN client and server applications Not compatible with Windows L2TP More difficult to use; may require a patch to the kernel VPNs are Less expensive than a modem pool. Internet connection replaces direct modem connection Networking Concepts – Eric Vanderburg ©2005
- 11. VLAN Implemented on switches Requires a router also Divides ports into logical sections Usually separated by subnet Networking Concepts – Eric Vanderburg ©2005
- 12. Routing Static routing – each path must be manually entered – same path is used each time Dynamic routing – router determines the best route based on available info Networking Concepts – Eric Vanderburg ©2005
- 13. Brouters Routes packets that use routable protocols Forwards packets that are not routable Useful in hybrid network with mixture of routable and nonroutable protocols May be identified as router with bridging capabilities Networking Concepts – Eric Vanderburg ©2005
- 14. Gateway Operates at layer 7 Translates between most dissimilar networks GSNW… Networking Concepts – Eric Vanderburg ©2005