Please explain in detail how to solve this, thanks! :) Consider a statically con
ID: 3841845 • Letter: P
Question
Please explain in detail how to solve this, thanks! :)
Consider a statically configured network according to the figure below (static configuration means that no network communication is needed to configure IP addresses, etc.), and assume that all devices recently have been powered on, so that all ARP and switch tables are empty. Use the notation that computer A has IP address A_Ip and MAC address A_MAC, etc. Computer A is connected to switch port 1, computer B to port 2, and so on. Now assume that computer A sends "ping" (ICMP echo request) to computer C, which responds with (ICMP echo reply). Thereafter computer B also sends "ping" to computer C, which sends a respond. a) Number each packet that is sent over the network as 1..N in the order they are sent, and list the packets showing type and relevant fields from the packet headers. b) Show for each of the computers A, B, C and D which of the packets they have received. c) Also show the content of the switch table in S, and use the packet nubering above to show when each field in the table is created.Explanation / Answer
Assume:
A-IP A-MAC
B-IP B-MAC
C-IP C-MAC
D-IP D-MAC
FF -- Broadcast MAC
255 -- Broadcast IP
As all are the new system and no ARP cache is there. When they are going to boot up, every system will send ARP packets (asking if anyone is there with their packets in the same LAN) by default and the necessary content of those packets are:
For A: A-IP, A-MAC, 255, FF
For B: B-IP, B-MAC, 255, FF
For C: C-IP, C-MAC, 255, FF
For D: D-IP, D-MAC, 255, FF
and after sending, they are going to receive ARP reply from the switch with all the IP Addresses (assuming all the systems are in the same VLAN).
So once this is done and all the systems are in the same VLAN, all the system will have ARP cache table with IP and MAC addresses.
So when A sends a ping to C. Ping packet will have:
A-IP, A-MAC, C-IP, C-MAC
The same way, when B sends a ping to C. Ping packet will have:
B-IP, B-MAC, C-IP, C-MAC
So to answer the question:
a.
2 packets will be sent.
1. ARP packet to let switch know the IP and MAC of the system.
ARP packet header will be:
A: A-IP, A-MAC, 255, FF
2. Ping packet to host C.
A-IP, A-MAC, C-IP, C-MAC
b.
Every host will receive broadcast ARP packets (which are sent by other hosts) and host C will receive two ping packets.
For example, host A will receive 3 ARP packets sent by B, C and D host.
c.
In the case of a switch, all the ARP packets would come to that switch at a time (approx) so it's really difficult to judge which would come first.
If ARP packets come in this way: first A's ARP, then B's ARP, then C's ARP, then D's ARP.
Then table would look like this:
ARP table of switch
A-MAC A-IP created first
B-MAC B-IP
C-MAC C-IP
D-MAC D-IP