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Cisco certified network associate. Welcome!. welcome!. Goal – Cisco Certified Network Associate, Cisco Certified Network Professional, and beyond! About Me Overall view of classes Switching Basics (frames, broadcast / collision domains, arp)
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Cisco certified network associate Welcome!
welcome! • Goal – Cisco Certified Network Associate, Cisco Certified Network Professional, and beyond! • About Me • Overall view of classes • Switching Basics (frames, broadcast / collision domains, arp) • Switching advanced (stp, portfast, root bridge, vtp pruning, trunking, port-channels) • Routing Basics (static, rip, ospf, eigrp) • Routing advanced (route redistribution, changing metrics) • Other awesome topics • NAT, IPv6, Binary / Hex conversion, subnet maths, summarization • PPP and Frame Relay • First interview question • Next…Topics to cover today
Topics to cover • Hardware (Where (decent places), what (3550, 3560, or 2950), why (emulation?) • Cables / cabling needs (Auto MDIX – medium dependent interface crossover) • Boot (ROMMON, flash, ROM, RAM, NVRAM, running-config, startup-config), diagnostics • Switching Basics • Models (TCP/IP, versus DoD) • Frames (hubs, repeaters, flooding, broadcast / collision domains) – examples • VLANing • Mac addressing (OUI vey) • Arp • CDP • VTP • Next…Hardware
Hardware • Where (decent places) • http://www.certificationkits.com/ • What to buy (3550, 3560, or 2950) • CCNA – 2 2950, or 3550, 2900 series (RAM!) • CCNP – Add 2 more 3550 and two more 2900 routers • TSHOOT Exam Topology • Why (emulation?) • GNS3 – Wireshark (http://www.gns3.net/download/) • Cables / cabling needs (Auto MDIX – medium dependent interface crossover) • 2960 3560 both have Auto MDIX otherwise crossover cables it is • http://monoprice.com • Next…Boot
Boot • 1. Bootstrap program ROMmon runs Power On Self Test (POST) • 2. Bootstrap checks the Configuration Register in startup config file • If nothing is there it will load from Flash • No flash it will try to load from a TFTP server (assuming that you have one set up on the network / program one in, ASA) • If no TFTP server you would have to manually enter TFTP info from ROMMON (SERVER = <tftp server>, SUBNET MASK=<subnet mask>, etc.) • 3. IOS found now it is loaded into RAM (Self-decompressing the image: ####...) • 4. Config file loaded from NVRAM (dir) into RAM if none found Setup dialogue • Next…Switching
Switching basics • Models (Layers, TCP/IP versus DoD, real world) • Vlanning (Broadcast, Collision domains)
Models • TCP / IP (A Pizza Sure Tastes Nice During Presentations) • Application – HTTP, everything • Presentation – Human to computer (Layer 6) • Session – Build and tear down of session (Layer 5) • Transport – TCP/UDP (Layer 4) – a.ka. segment • Network – IP Address (Layer 3) – a.k.a. packet • Data Link – MAC (Layer 2) – a.k.a. frame • Physical (Layer 1) • DoD • Application (5 and up) • Host-To-Host Layer (4) • Internet Layer (3) • Network Interface Layer (1 and 2) • Next…Vlanning
VLANing • Broadcast Domains – Stops at a Router (L3 device edge) • Collision Domains (hubs, repeaters) – Collision, hardware needs to listen for silence • Switches eliminate this by moving the collision domain to the specific port • Next…MAC Addresses
MAC addresses • Mac address – unique identifier on a broadcast domain • Entire thing 6 bytes (48 bits) • OUI (first 3 bytes – or 24 bits) • If someone says, “For ease of use I need to duplicate my mac, can I?” What do you ask them? • Next…Address Resolution Protocol
Address resolution protocol • Arp requests – Hey who has an ip address of 192.168.0.1? • Send a broadcast out ff:ff:ff:ff:ff:ff • No MAC supplied in the arp request • Arp replies – Hey I have it! • GNS3 example • Loop traffic? (https://supportforums.cisco.com/message/3005684#3005684) - self looped port • do wr, copy runnning-config startup-config, wr mem • Next…Cisco Discovery Protocol
Cisco discovery protocol • Cisco device sends out a multi-cast to 01:00:0c:cc:cc:cc with its mac address as source • No two way communication just multicasts
References • http://www.9tut.com/cisco-router-boot-sequence-tutorial • http://www.petri.co.il/introduction-to-the-osi-model.htm