prevlig exect mode en

conf t

log sync

exect timeout 0 never time out

Static Routes
A static route will not change until the admin manually reconfigures it. Routes tha are statico routs will be identified in the routing table with the prefix S.

Dynamically Updated Routes (Dynamic Routes)
Using dynamic routes will automatically created and maintained the routing protocols. It does this by exchanging routing information with other routers in the network. Dynamically updated routes will be identified in the routing table with the prefix that corresponds to the type of routing protocol that is on the other router

Default Route
Default route is like a static route but it will specife a gateway to use if the routing table does not contain a path for the destination network.

Configuring Static Routes
R1>enable
R1#
R1#config terminal
R1(config)# ip route [destination_network] [subnet_mask] [gateway_address] or ip route [destination_network] [subnet_mask] [exit_interface]

Distance Vector
Distance – How far away is the network from this router?
Vector – In which direction should the packet be sent to reach this network?
When using distance to work out how to get to the destination it will use route cost or metric measurements like this
Number of hops
Administrative cost
Bandwidth
Transmission speed
Likelihood of delays
Reliability
to find out how to get there

RIP
Routing Information Protocol (RIP) is a distance vector.
RIP uses this to find the way to the destination
Uses hop count as the metric for path selection
Defines a hop count greater than 15 as an unreachable route
Sends routing table contents every 30 seconds

Config RIP
Router(config)#router rip
Router (config-router)#version 2
Router(config-router)#network [network_number]

Config BGP
router bgp [AS_number]
neighbor [IP_address] remote-as [AS_number]
network [network_address]

POP
Ware ypu connect to the ISP

Dialup
is inexpensive
uses any phone line
slow connection
used were high speed connection can not be used

DSL (Digital subscriber line)
more expensive than dialup
has a faster connection
uses telephone lines
uses a modem to separates the DSL from interfeingwith the phone

Cable modem
connect through a cable television port
faster then DSL
more expensive than DSL

Satellite
connect via a satellite 
uses radio signals to send to the satellite

Bandwidth = bits per second (bps). Some of the newer higher speeds are measured in kilobits per second (kbps), megabits per second (Mbps), or gigabits per second (Gbps).

Three  types of high-bandwidth connection

T1 connection can transfer data up to 1.544 Mbps. T1 connections are symmetrical, this means that the upload speed is the same as the download speed

T3 connections can transfer data up to 45 Mbps. T3 is more expensive than a T1

Internet hierarchy
it starts with the ISP organizations. Then the ISP POPs connect to an Internet Exchange Point (IXP) which join the all the ISP together to access each other so they can exchange information.

Internet backbone has groups of networks owned by lots of different organizations which is interconnected through IXPs and private peering connections.

Tier 1
ISPs are the top of the hierarchy. Tier 1 is were all the ISPs are  connect directly to each other through private peering, physically joining their network backbones together to create a global Internet backbone.

Tier 2
More ISPs are the next tier in terms of backbone access. Tier 2 ISPs lets countries connect to other countries. Tier 2 ISPs will pay Tier 1 ISPs to carry their infomation to other parts of the world.

Tier 3
ISPs are the last level of the backbone. Tier 3 ISPs are found cities and will provide customers access to the Internet. Tier 3 ISPs have to  pay Tier 1 and 2 ISPs for access to the global Internet.

The Cisco Internetwork Operating System (IOS) is the software that goes on to a Cisco device to enables it to send and receive network traffic using a wired or wireless network.

Router Bootup Process
1. Power-on self test (POST) and load the bootstrap program.

2. Locate and load the Cisco IOS software.

Bootstrap program fines and loads the cisco IOS software into RAM. You can have the Cisco IOS files in one of three places: flash memory, a TFTP server, or another location indicated in the startup configuration file, by default the Cisco IOS software will load from flash memory. You need to change the configuration settings if you want it to load from one of the other locations.

3. Locate and execute the startup configuration file or enter setup mode.

When Cisco IOS software is loaded, the bootstrap program goes and searches for the startup configuration file in NVRAM. The startup configuration file has the previously saved configuration commands and parameters, including interface addresses, routing information, passwords, and other configuration parameters.

Startup Configuration File
Startup Configuration File has the saved configuration file which sets the properties of the device when it starts up. The Startup Configuration File is stored on non-volatile RAM (NVRAM), which means it is saved even when the power is off.

Transport Protocol
Transmission Control Protocol (TCP) is the transport protocol that manages the conversations from a web server to a web client. It formats the HTTP messages into parts so it can be sent to the destination host. TCP can also provides flow control and makes sure the packets gets to the hosts

Internetwork Protocol
Internet Protocol (IP) is the most common internetwork protocol. This protocol takes the TCP formatted parts and assigns the logical addressing, and encapsulating them in to packets for routing to the destination.

Application layer protocals
HTTP, FTP, DSN, SMTP, Telnet and DHCP

Transport layer protocals
TCP and UDP

Internetwork layer protocals
IP

TCP: sends the message in small pieces known segments. TCP keeps track of how many segments have been sent to the host, if the sender does not receive an acknowledgement within a certain amount of time,  it then sends the same segments out because it assumes that the segments were lost.

UDP: sends the message but does not require aknowledgment. UDP is used for things like streaming audio, video and voice over IP (VoIP).

Domain Name System (DNS)
uses a name to get the IP address of a specific server, DNS are are oganized on the internet by groups and domains
Domains are .com .edu and .net

Class              Host               Networks

A                   2^24-2                 2^7

B                   2^16-2                 2^14

C                   2^8-2                   2^21

Asymmetric- when download transfer rate is different to the upload transfer rate, used in homes mostly.

Symmetric- when both transfer rates are the same, mostly used in business or individuals hosting servers.

IP packets have a header that holds the contains of the source and destination IP addresses, it also has control information that describes the packet to the network devices; eg routers.. IP is packet is also called a datergram

IP packet size can only be 64 to 1500 bytes for ethernet networks

ping utility- is when you measure the time it takes to send a packet from the source to the destination using test pakets it also tells you if you had a successful transmission

traceroute utility- traces the route from sourcec to destination. A router that the packet gose through is called a hop, it shows each hop alog the way and how long each one takes. traceroute utility is called tracert

Devices in internet cloud

routers, switches, DSL access multiplexer (DSLAM), cable modem termination system (CMTS), 

Equipment uesed by ISP is high-end, high-speed devices they use this equipment because it need to be running at near 100%.

Network equipment in home and small business are lower-end, lower-speed devices and can not handle large trafic

Twisted Pair(TP)- most commonly use in network cabling,
transmision is sensitive to interference or noise these can lower the data rate of the cable, afected mostly by EMI (Electromagnetic Interference) a type of noise, crosstalk is interference which occurs signal from one cable is leaked out and enters ajacent cable,
more turns in cable the more resistants it is to interference

Coaxial Cable- made out of copper or aluminum, used in cable TV andsatellit components

Fiber Optic- made out of glass or plastic, very high bandwidth, used in backbone networks large data centers and telephon companies
it has 5 layers the jacket, the strengthening material the buffer the cladding the core

Multimode- less expensive, more widely used, LED is usually the source of the pulses of light used to send data, multiple rays of light carrying data being tansmitted at the same timeand takes a separate path, good for links up to 2000 meters

Single mode- data can only go oneway, light source is LED laser, more expansive, higher data transfer, good for links up to 3000

Straight-through Cables- most common , wire gos to same pins at both ends, uses both T568A andT568B wiring schemes

Crossover Cable- use both wiring schemes one at each end

unlike devices- use a straight through cable, RJ-45 connector ueses pin 1 and 2 to transmit and 3 and 6 to recieve on a PC, on a switch the RJ-45 connector ueses pin 3 and 6 to transmit and 1 and 2 to recieve , othe examples are switches to router and hub to PC

like devices- use a crossover cable, examples ar switch port to switch port, switch port to hub port, hub port to hub port, router port to router port, PC to router port, and PC to PC

what are

Peripherals-cameras, scanners and locally attached printers

hosts-computers, servers and network printers