Cisco Capítulo 1 ISP

The Internet is a worldwide, publicly accessible network of networks.

In the beginning, the Internet was used strictly for scientific, educational, and military research. In 1991, regulations changed to allow businesses and consumers to connect as well.

A standard is a set of rules that determines how something must be done. is the end result of a comprehensive cycle of discussion, problem solving, and testing. When a new standard is proposed, each stage of the development and approval process is recorded in a numbered Request for Comments (RFC) document so that the evolution of the standard is tracked.

the device must connect through an Internet service provider (ISP). An ISP is a company or organization through which a subscriber obtains Internet access.

In addition to offering connection to the Internet, an ISP can offer other services to subscribers, including:

Equipment co-location - A business may opt to have some or all internal network equipment physically located on the ISP premises.

Point of Presence (POP) - A business has the option of connecting to the ISP through POP, using a variety of access technologies. (Physical location at an ISP, directly)

Delivering internet service

Dialup access is an inexpensive option that uses any phone line and a modem, a user calls the ISP access phone number. Is the slowest connection option, and is typically used by mobile workers and in areas where higher speed connection options are not available.

Faster connection. DSL also uses telephone lines, but unlike dialup access, DSL provides a continuous connection to the Internet. This connection option uses a special high-speed modem that separates the DSL signal from the telephone signal and provides an Ethernet connection to a host computer or LAN. (distance)

A cable modem is a connection option offered by cable television service providers. The Internet signal is carried on the same coaxial cable that delivers cable television. A special cable modem separates the Internet signal from the other signals carried on the cable.


Satellite connection is an option offered by satellite service providers. The user's computer connects through Ethernet to a satellite modem that transmits radio signals to the nearest Point of Presence, or POP, within the satellite network.

Bandwidth is measured in bits per second (bps). Higher bandwidth speeds are measured in kilobits per second (kbps), megabits per second (Mbps), or gigabits per second (Gbps).


T1 connections transmit data up to 1.544 Mbps. T1 connections are symmetrical, meaning that the upload bandwidth is the same as the download bandwidth. A medium-sized business may need only one T1 connection. E1 is a European standard that transmits data at 2.048 Mbps.

T3 connections transmit data up to 45 Mbps. Although considerably more expensive than a T1 connection, larger businesses may need a T3 connection to accommodate the number of employees. Large businesses with multiple locations might use a combination of T1 and T3 lines. E3 is a European standard that transmits data at 34.368 Mbps.

Metro Ethernet offers a wide range of high-bandwidth options, including Gbps links. Large companies with many branches in the same city, such as banks. Metro Ethernet connects the main office location and all the branches using switched technology. Metro Ethernet allows the transfer of large amounts of data faster and less expensively than other high-bandwidth connection options.

Individual computers and business networks connect to the ISP at the POP. POPs are located at the edge of the ISP network and serve a particular geographical region. They provide a local point of connection and authentication (password control) for multiple end users.

The ISP POPs connect to an Internet Exchange Point (IXP). An IXP or NAP is where multiple ISPs join together to gain access to each other's networks and exchange information. The Internet backbone consists of this group of networks owned by various organizations and interconnected through IXPs and private peering connections.
Internet backbone is like an information super highway that provides high-speed data links to interconnect the POPs and IXPs in major metropolitan areas around the world. The primary medium that connects the Internet backbone is fiber-optic cable.

Tier 1 ISPs are the top of the hierarchy. are huge organizations that connect directly with each other through private peering, physically joining their individual network backbones together to create the global Internet backbone. Within their own networks, the Tier 1 ISPs own the routers, high-speed data links, and other pieces of equipment that join them to other Tier 1 ISP networks. This includes the undersea cables that connect the continents.

Tier 2 ISPs are the next tier in terms of backbone access. Tier 2 ISPs can also be very large, even extending across several countries, To provide their customers with global Internet access, some Tier 2 ISPs pay Tier 1 ISPs to carry their traffic to other parts of the world. Some Tier 2 ISPs exchange global traffic with other ISPs less expensively through public peering at IXPs. A large IXP may bring together hundreds of ISPs in a central physical location for access to multiple networks over a shared connection. (Countries)

Tier 3 ISPs are the farthest away from the backbone. Tier 3 ISPs are generally found in major cities and provide customers local access to the Internet. Tier 3 ISPs pay Tier 1 and 2 ISPs for access to the global Internet and Internet services. (Cities)

The ping command tests the accessibility of a specific IP address. The ping command sends an ICMP (Internet Control Message Protocol) echo request packet to the destination address and then waits for an echo reply packet to return from that host. ICMP is an Internet protocol that is used to verify communications.

It measures the time that elapses between when the request packet is sent and the response packet is received. The ping command output indicates whether the reply was received successfully and displays the round-trip time for the transmissions. (Reachable and time)

To use the ping command, enter the following command at the Cisco command line interface (CLI) router prompt or at the Windows command prompt:

ping

where is the IP address of the destination device.

For example, ping 192.168.30.1.

The traceroute utility displays the path that a packet takes from the source to the destination host. Each router that the packet passes through is called a hop. Traceroute displays each hop along the way. It also calculates the time between when the packet is sent and when a reply is received from the router at each hop.

If a problem occurs, use the output of the traceroute utility to help determine where a packet was lost or delayed. The output also shows the various ISP organizations that the packet must pass through during its journey from source to destination.

Scalability is the capacity of a network to allow for future change and growth. Scalable networks can expand quickly to support new users and applications without affecting the performance of the service being delivered to existing users.
The most scalable devices are those that are modular and provide expansion slots for adding modules.

Roles and responsabilities of an ISP

Customer Service receives the order from the customer and ensures that the specified requirements of the customer are accurately entered into the order tracking database.

Planning and Provisioning determines whether the new customer has existing network hardware and circuits and if new circuits need to be installed.

The On-site Installation is advised of which circuits and equipment to use and then installs them at the customer site.

The Network Operations Center (NOC) monitors and tests the new connection and ensures that it is performing properly.

The Help Desk is notified by the NOC when the circuit is ready for operation and then contacts the customer to guide them through the process of setting up passwords and other necessary account information.