TCP/IP:
5 Layers in contrast to 7 Layer OSI: Physical, Data-link, Internet, Host-to-Host, & Application
Physical+Datalink = N/w i/f layer: Defines the Electrical/Optical Protocols, Mechanical Protocols,
Functional protocols, Procedural Protocols
IP Flags: 010 – DF, 001 – More fragments, 000 – End of fragments
Options: Strict source routing, Loose source routing, Record route, Timestamp route
ToS: 3 bit Precedence, 5 bit ToS. Now mostly used as 6 bit DSCP , 2 bit ECN (11)
Misc:
ARP – cisco default timeout = 4hrs,
PROXY-ARP – default enabled per interface
GRATUITOUS ARP- default disabled per interface – used for duplicate address detection
IP redirect enabled by default.
Max size of IP packet: 65535 octets
