Chapter 1 Review Questions
1. There is no difference. Throughout this text, the words “host” and “end system” are
used interchangeably. End systems include PCs, workstations, Web servers, mail
servers, PDAs, Internet-
...
Chapter 1 Review Questions
1. There is no difference. Throughout this text, the words “host” and “end system” are
used interchangeably. End systems include PCs, workstations, Web servers, mail
servers, PDAs, Internet-connected game consoles, etc.
2. From Wikipedia: Diplomatic protocol is commonly described as a set of international
courtesy rules. These well-established and time-honored rules have made it easier for
nations and people to live and work together. Part of protocol has always been the
acknowledgment of the hierarchical standing of all present. Protocol rules are based on
the principles of civility.
3. Standards are important for protocols so that people can create networking systems and
products that interoperate.
4. 1. Dial-up modem over telephone line: home; 2. DSL over telephone line: home or
small office; 3. Cable to HFC: home; 4. 100 Mbps switched Ethernet: enterprise.
5. HFC bandwidth is shared among the users. On the downstream channel, all packets
emanate from a single source, namely, the head end. Thus, there are no collisions in
the downstream channel.
6. In most American cities, the current possibilities include: dial-up; DSL; cable modem;
fiber-to-the-home.
7. Ethernet LANs have transmission rates of 10 Mbps, 100 Mbps, 1 Gbps and 10 Gbps.
8. Today, Ethernet most commonly runs over twisted-pair copper wire. It also can run over
fibers optic links.
9. ADSL: up to 24 Mbps downstream and 2.5 Mbps upstream, bandwidth is dedicated;
HFC, rates up to 42.8 Mbps and upstream rates of up to 30.7 Mbps, bandwidth is
shared. FTTH: 2-10Mbps upload; 10-20 Mbps download; bandwidth is not shared.
10. There are two popular wireless Internet access technologies today:
a. Wifi (802.11) In a wireless LAN, wireless users transmit/receive packets
to/from an base station (i.e., wireless access point) within a radius of few tens
of meters. The base station is typically connected to the wired Internet and thus
serves to connect wireless users to the wired network.
b. 3G and 4G wide-area wireless access networks. In these systems, packets are
transmitted over the same wireless infrastructure used for cellular telephony,
with the base station thus being managed by a telecommunications provider.
This provides wireless access to users within a radius of tens of kilometers of
the base station.
11. At time t0 the sending host begins to transmit. At time t1 = L/R1, the sending host
completes transmission and the entire packet is received at the router (no propagation
delay). Because the router has the entire packet at time t1, it can begin to transmit the
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packet to the receiving host at time t1. At time t2 = t1 + L/R2, the router completes
transmission and the entire packet is received at the r
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