Description / paper instructions
Problem 1- IP Fragmentation
Consider sending 8000-byte datagram into a link that has an MTU of 1000 bytes.
a) How many fragments are generated?
b) What are their characteristics (i.e. what are the flags and offset values for each (Assume that the DF flag was not set : )
Solution: Assume that no optional fields of the IP header are in use (i.e. IP header is 20 bytes)
c) When a large datagram is fragmented into multiple smaller datagrams, where are these smaller datagrams reassembled?
d) Explain how traceroute works. Include a traceroute to a host at least 9 hops away.
Problem2: CIDR -A router has the following (CIDR) entries in its routing table:
Destination Gateway Next hop
197.46.56.0/21 Interface 0
197.46.60.0/21 Interface 1
196.53.40.0/22 Router 1
default Router 2
1. For each of the following IP address, what does the router do if packets with the following addresses arrive?
(a) 197.46.63.10/21
(b) 197.46.67.14/21
(c) 135.46.52.2 /22
(d) 196.53.40.7 /24
(e) 196.53.56.7/24
2. What is the relationship between the “gateway” and “interface” fields?
Problem 3- Network Layer
1. How does a host get an IP address? How does a network get the subnet part of an IP address? How does a provider get a block of IP addresses? What is the principle behind these procedures?
2. A router has five interfaces. How many IP addresses will it have?
3. What problem is tackled by Network Address Translation (NAT)? Please briefly describe what NAT does.
Problem 4- Data Link Layer:
a) Suppose nodes A, B, and C each attach to the same broadcast LAN (through their adapters). If A sends thousands of IP datagrams to B with each encapsulating frame addressed to the MAC address of B, will C’s adapter process these frames? If so, will C’s adapter pass the IP datagrams in these frames to the network layer C? How would your answers change if A sends frames with the MAC broadcast address?
b) How big is the MAC address space? The IPv4 address space? The IPv6 address space?
c) State the reason why an ARP query is sent within a broadcast frame? When a response sent within a frame with a specific destination MAC address?
d) In CSMA/CD, after the sixth collision, what is the probability that a node chooses K=10? In case, if the result is K=4, then it corresponds to a delay of how many seconds on a 10Mbps Ethernet?
e) Suppose a computer is moved from one department to another. Does the physical address need to change? Does the IP address need to change? Does it make a difference if the computer is a laptop? |