Ethernet / ARP

By | 28/07/2014

Ethernet

CSMA/CD Carrier sense multiple access / collision detect  (IEEE 802.3)

Ethernet Frame – From 64 to 1518 bytes

kb-ethernetframe

EtherTypes:

0x0806 – ARP Frame

0x0800 – IPv4 Frame

0x8100 – IEEE 802.1q Frame

0x86DD – IPv6 Frame

Jumbo Frames – Ethernet frames with more than 1500 bytes of payload to increase efficiency. Up to 9000 bytes.

OUI Identifier – http://standards.ieee.org/develop/regauth/oui/public.html

Manufacturer ID

ARP

ARP Address resolution protocol IP -> MAC

Ethernet broadcast request – who is IP?

IP host will respond

Windows commands

arp -a – displays contents of the ARP table in the computer

arp -a IP

arp -d * – removes all the ARP entries

arp -s IP MAC – adds a static ARP entry

Cisco commands

show arp

show mac address-table

clear mac address-table

debug arp