Data Communications II Autumn 2004
Problem set 2. (11.10.2004)
- Suppose that the partial acknowlegdements of NewReno are in
use. How does the TCP handle the situation where after a succesfull
transmit of one segment, three following segments will get lost?
After that there are no problems in the transmission. The congestion
window is 8 MSS. The round-trip-time is 100 ms and the
retransmission timer is set to 200 ms. Only the congestion window
limits the sending.
- RED buffer and ECN
- How does a RED buffer work? What
are its benefits?
- A TCP implementation wants to use ECN (Explicit Congestion
Notification). What extra functionalities are needed in TCP and IP
protocols? How is the ECN usage negociated? Suppose a segment on a
TCP connection using ECN ends up into congestion. How does the
information about this reach the sender and how does the sender
behave after that.
- IP protocol and large packets
- How large amounts of data can be
sent using IP protocols? What factors constrain the size of an IP
datagram?
What is the maximum size of the IP
datagram?
- The supercomputer A wants to send
messages of 262144 bytes to another supercomputer B using IPv4
protocol. How is it done? What happens if a datagram sent has to
pass a network that cannot transfer so big datagrams?
- Is it possible for IPv6 to handle datagrams of 264 144
bytes? How is it done? What happens if a network on its way to the
destination cannot handle so large datagrams?
- Show the format of the IPv6
message when
- the IP datagram carrying a TCP
segment is using the authentication header AH,
- the IP datagram has to travel
from the machine H1 to machine H2 strictly just through the routers
A, B, C and D. How do the routers between handle this IP datagram?
- What is the status of IPv6 now? To
what extend is it deployed and used? What is 6Bone? Look for
information in WWW or otherwhere.
- What are the network addresses and
host addresses of the IP address 192.31.63.18
- when using class addresses,
- when using classless addressing
(CIDR) 192.31.63.8/20,
- when using classless addressing
and a subnet mask, with 28 ones in the beginning and rest of the
mask zeroes?
- How is the IPv4 address
192.31.63.18 given as an IPv6 address.
- When an organization is using
both classless addresssing and subnetting, what kind information is
stored in the routing tables of the routers belonging to that
organization? How do these routers route packets?