chap 1 Computer networks and the
Internet
1.1.1 a nuts and bolts description - correct answer ✔✔all devices are called hosts or end systems
each systems are connected together by network of communication links and packets switches
the transmission rate of link measured in bits/second
packet switches come in many shapes and flavors such as routers and link-layer switches
end systems access the Internet through Internet Service Providers (ISPs) including residential ISPs such
as local cable or telephone companies; corporate ISPs, university ISPs. ISPs that provide wifi access in
airports, hotels, coffee shops, and other public places, and cellular data ISPs, providing mobile access to
our smartphones and other devices
protocols that control the sending and receiving of information within the internet.
Internet standards are developed by the Internet Engineering Task Force (IETF)
the IETF standards documents are called requests for comments (RFCs)
1.1.2 A services description - correct answer ✔✔the applications are said to be distributed applications,
since they involve multiple end systems that exchange data with each other.
each systems attached to the Internet provide a socket interface that specifies how a propram running
on one end system asks the internet infrastructure to deliver data to a specific destination program
running on another end system.
, 1.1.3 what is a protocol ? - correct answer ✔✔a protocol defines the format and the order of messages
exchanged between two or more communicating entities, as well as the actions taken on the
transmission and/or receipt of a message or other event
mastering the field of computer networking is equivalent to understanding the what, why, and how
networking protocols
1.2.1 access networks - correct answer ✔✔host = end system = clients and servers.
the two most prevalent types of broadband residential access are digital subscriber line (DSL) and Cable.
while DSL makes us of the telco's existing local telephone infrastructure, cable internet access makes use
of the cable television company's existing cable television infrastructure.
one important characteristic of cable internet access is that it is a shared broadcast medium. In
particular, every packet sent by head end travels downstream on every link to every home and every
packet sent by a home travels on the upstream channel to the head end.
For this reason, if several users are simultaneously downloading a video file on the downstream channel,
the actual rate at which each user receives its video file will be significantly lower than the aggregate
cable downstream rate.
On the other hand, if there are only few active users and they are all web surfing, then each of the users
may actually receive web pages at the full cable downstream rate, becasue the users will rarely request a
web page at exactly the same time.
Fiber to the home (FTTH). there are two competing optical-distribution network architectures that
perform this splitting: active optical network (AONs) and passive optical networks (PONs)
wide-area wireless access 4G (a fourth generation of wire-area wireless networks, LTE (Long-Term
Evolution)
Internet
1.1.1 a nuts and bolts description - correct answer ✔✔all devices are called hosts or end systems
each systems are connected together by network of communication links and packets switches
the transmission rate of link measured in bits/second
packet switches come in many shapes and flavors such as routers and link-layer switches
end systems access the Internet through Internet Service Providers (ISPs) including residential ISPs such
as local cable or telephone companies; corporate ISPs, university ISPs. ISPs that provide wifi access in
airports, hotels, coffee shops, and other public places, and cellular data ISPs, providing mobile access to
our smartphones and other devices
protocols that control the sending and receiving of information within the internet.
Internet standards are developed by the Internet Engineering Task Force (IETF)
the IETF standards documents are called requests for comments (RFCs)
1.1.2 A services description - correct answer ✔✔the applications are said to be distributed applications,
since they involve multiple end systems that exchange data with each other.
each systems attached to the Internet provide a socket interface that specifies how a propram running
on one end system asks the internet infrastructure to deliver data to a specific destination program
running on another end system.
, 1.1.3 what is a protocol ? - correct answer ✔✔a protocol defines the format and the order of messages
exchanged between two or more communicating entities, as well as the actions taken on the
transmission and/or receipt of a message or other event
mastering the field of computer networking is equivalent to understanding the what, why, and how
networking protocols
1.2.1 access networks - correct answer ✔✔host = end system = clients and servers.
the two most prevalent types of broadband residential access are digital subscriber line (DSL) and Cable.
while DSL makes us of the telco's existing local telephone infrastructure, cable internet access makes use
of the cable television company's existing cable television infrastructure.
one important characteristic of cable internet access is that it is a shared broadcast medium. In
particular, every packet sent by head end travels downstream on every link to every home and every
packet sent by a home travels on the upstream channel to the head end.
For this reason, if several users are simultaneously downloading a video file on the downstream channel,
the actual rate at which each user receives its video file will be significantly lower than the aggregate
cable downstream rate.
On the other hand, if there are only few active users and they are all web surfing, then each of the users
may actually receive web pages at the full cable downstream rate, becasue the users will rarely request a
web page at exactly the same time.
Fiber to the home (FTTH). there are two competing optical-distribution network architectures that
perform this splitting: active optical network (AONs) and passive optical networks (PONs)
wide-area wireless access 4G (a fourth generation of wire-area wireless networks, LTE (Long-Term
Evolution)
