Page 288 - DCAP101_BASIC_COMPUTER_SKILLS

Unit 13: Internet

Cable Internet Notes

Dial-up
ISDN
Modem
DSL

FTTH
Wi-Fi

Typical business-type connection
DSL
Ethernet technologies

Leased line
SHDSL

13.7.2 Locality
When using a dial-up or ISDN connection method, the ISP cannot determine the caller’s
physical location to more detail than using the number transmitted using an appropriate
form of Caller ID; it is entirely possible to e.g. connect to an ISP located in Mexico from
the USA. Other means of connection such as cable or DSL require a fixed registered connection
node, usually associated at the ISP with a physical address.

13.7.3 Hosting ISPs

Hosting ISPs routinely provide email, FTP, and web-hosting services. Other services
include virtual machines, clouds, or entire physical servers where customers can run their
own custom software.

13.7.4 Transit ISPs
Just as their customers pay them for Internet access, ISPs themselves pay upstream ISPs for
Internet access. An upstream ISP usually has a larger network than the contracting ISP and/
or is able to provide the contracting ISP with access to parts of the Internet the contracting
ISP by itself has no access to.
In the simplest case, a single connection is established to an upstream ISP and is used to
transmit data to or from areas of the Internet beyond the home network; this mode of
interconnection is often cascaded multiple times until reaching a Tier 1 carrier. In reality,
the situation is often more complex. ISPs with more than one point of presence (PoP) may
have separate connections to an upstream ISP at multiple PoPs, or they may be customers
of multiple upstream ISPs and may have connections to each one of them at one or more
point of presence.

13.7.5 Peering

Main article: Peering
ISPs may engage in peering, where multiple ISPs interconnect at peering points or Internet
exchange points (IXs), allowing routing of data between each network, without charging one
another for the data transmitted—data that would otherwise have passed through a third
upstream ISP, incurring charges from the upstream ISP.

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