ITS 629: Computer Network Design Instructor Information: Mark Jamil questions@markjamil.com

Network Cabling There are many different types of Ethernet cable. Max Speed Length Cat5 100Base-TX Cisco - “Fast Ethernet” 100 Mb/s 100 m Cat5e 1GBase-TX 1 Gb/s Fiber (850nm/50μm) 1GBase-SX 550 m Fiber (1300nm/9μm) 1GBase-LX 2000 m Cat6 10GBase-T 10 Gb/s Cat6a 10GBase-LW Cat7a 40GBase-T 100 Gb/s 50 m 100GBase-T 15 m Fiber (1550nm/9μm) 100GBase-ZR 80,000 m

Fiber vs Copper vs. Copper Pair Fiber Short Distance, usually up to 100m (sort of) Long Distance, up to 80km (so far) Can provide power No Current Interference (crosstalk) and signal loss No electricity Cheaper Expensive and can be confusing

Wireless? Wireless is a good technology but suffers from inherent problems. Collisions – Interference between signals on the same frequency. Works at half duplex. Limits the number of connections you can make. Many devices can interfere with signals. A microwave frequently interfere with 2.4Ghz signals. Other people working on same frequency is a problem. Security Anyone in the area or path can capture your wireless communication and use it to decrypt your data. Attenuation (signal loss) For wireless, signal loss related to square of the distance.

Copper Ethernet Wires Straight Through Cable Cross-Over Cable In general, we use two standards when making Ethernet wires. 568A – Colors arranged as such WG, G, WO, Bl, WBl, O, WBr, Br 568b – Colors arranged as such WO, O, WG, Bl, WBl, G, WBr, Br Straight Through Cable Cross-Over Cable

Cross-Over vs. Straight Through Straight through cables connect: PC to Switch Switch to Router Cross over cables connect: PC to PC Switch to Switch Router to Router PC to Router In the real world, many devices have something called auto-negotiation (aka auto-MDIX). These devices can figure out what type of cable you are using. Do not assume this is always true!

Serial Interfaces? In the old days, these were faster than 10Base-T Speed depends on clock rate and bandwidth Fastest I have seen is about 50Mb/s Cables were very expensive compared to copper Cisco recommends 8Mb/s max on serial.

Cisco Modules vs. WIC’s WIC MODULE In GNS3 you probably noticed that you can add modules and something called WIC’s to your router. Network Modules NM or NME Large interface cards WAN Interface Card WIC or HWIC or EHWIC Small interface cards WIC MODULE