ELLIOT'S CISCO NOTES
for future reference by me for me
these are very unorganized!!!! dont feel like retyping them
lesson 3
network protocol overview
network communications protocol
allows two or more devices to communicate over one or more networks.
examples include ip, tcp, http
network security protocols
secures data to provide authentication, integrity, and encryption
examples include ssh, ssl, tsl
routing protocols
allows routers to exchange route information, compare it, and select the quickest option availible
examples include ospf, bgp
service discovery protocol
used for the automatic detection of devices or services
examples include dhcp, dns
general terms
network protocol suite
a group of inter related protocols necessary to perform a communication function
open standard protocol suite
freely available, can be used by any vendor on their hardware
standards based protocol suite
endorsed by the networking industry, and approved by a standards organization. insures that products from different origin can interoperate
tcp/ip layers
4 - application: represents data to users, plus encoding and dialog control
3 - transport: supports communication between various devices across diverse networks
2 - internet: determines the best path through the network
1 - network access: controls the hardware devices and media that make up the network
tcp/ip layers examples
(// means subcategory, //// means item in said subcategory)
application layer
// name system
////DNS [domain name system]
*
// host config
//// dhcpv4
//// dhcpv6
//// slaac
*
//// smtp
//// pop3
//// imap
*
// file transfer
//// ftp [file transfer protocol]
//// sftp
//// tftp
*
// web and web service
//// http
//// https
//// rest
transport layer
// connection
//// tcp
*
// connectionless
//// udp
internet layer
// internet protocol
//// ipv4
//// ipv6
//// nat
*
// messaging
//// icmpv4
//// icmpv6
//// icmpv6 nd
*
// routing protocols
//// ospf
//// eigrp
//// bgp
network access layer
// address resolution
//// arp
*
// data link protocols
//// ethernet
//// wlan
application -> transport -> internet -> network access
content layer -> rules layer -> physical layer
computer receiving: ethernet -> ip -> tcp -> data
computer encapsulating: data -> tcp -> ip -> ethernet
osi model layers
7 - application: contains protocols used for process-to-process communications
6 - presentation: provides representaions of data being transferred between the application layer
5 - session: provides services to the presentation layer to organize its data exchange
4 - transport: defines services to segment, transfer, and reassemble data between end devices
3 - network: exchanges individual pieces of data over the network between end devices
2 - data link: describes methods for exchanging data frames between devices over a common media
1 - physical: decribes the mechanical, electrical, functional, and procedural means to activate, maintain, and de-activate physical connections for a bit transmission to and from a network device
ip addresses
there are two parts to an ip address: the network and host portion
network portion[prefix]: the left most part of the address. indicates what network the device is on. all devices on the same network have the same network portion,
host portion[interface id]: remaining part of the address. identifies a specific device on the network. this portion is unique to each device.
example: 123.456.7.890
123.456.7. is the network portion
890 is the host portion
subnet mask divides the 2
mac versus ip
mac: identifies devices locally
ip: identifies devices globally
enable secret: gives extra security to enable password
enable password: priv exec mode, global ect
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