Consider the network design below a. Explain the following network design. b. Su
ID: 3862252 • Letter: C
Question
Consider the network design below
a. Explain the following network design.
b. Suppose all of the ARP tables are up to date. Enumerate all the steps required for sending an IP datagram from Host E to Host B. If any steps are repeated, just indicate so in your answer.
b. Assuming that the ARP table in the sending host is empty (and all other tables are up to date). Explain how this changes the scenario in (a) and enumerate any new steps required for sending the datagram.
A 192.168.1.001 192.168.3.001 192.168.2.001 00-00-00-00-00-00 44-44-44-44-44-44 77-77-77-77-77-77 Router 1 Router 2 LAN LAN LAN 192.168.2.002 192.168.2.003 L 192.168.1.002 192.168.3.002 22-22-22-22-22-22 33-33-33-33-33-33 55-55-55-55-55 SS-SS-SS-SS-SS-SS 192.168.2.004. B 192.168.1.003 66-66-66-66-66 192.168.3.003 11-11-11-11-11-11 99-99-99-99-99-99Explanation / Answer
The above network design contains 2 routers having respective ip address and mac address on each of the side.
And also 3 Ethernet connections with each one having 2 hosts and with their respective ip addressess and mac addresses of the hosts.
If any packet sent from the any host, the packet will sent to router and then router will decide to where to send it by looing at the destination ip in the packet. because routers are working in network layer, so they can look into the packets.
B
ARP(address resolution protocol) is a protocol used by the internet protocal (IP) to map ip network addresses to the hardware addressess (mac address) used by a datalink protocol.
whenever we need to send a packet from one host to another host, we need both ip address and mac address of the destination's host. Sometimes we know the ip address of the destination host but we dont know the mac address. In that situation we use the ARP protocol. and ARP maintains a cache (table) in which MAC addresses are mapped to ip addresses.
In the First situation, all the ARP table are up to date and host E is wants to send packet to host B.
Because all the ARP tables are up to date, host E have the both ip address and mac address, so host E will send the packet to Router with destination addresses of the host B. Router will send the packet to other router with destination address of the host B, the router will send the packet to host B by checking both ip address and mac address.
In the Second situation Host E's ARP table is empty. that means host E dont know the mac address of the host B. In this situation host E will broadcast the packet with source address as its own ip address and mac address and desitnations ip as host E's ip address and destination Mac address as zeros. The broadcased packet will reach to all the hosts but except host B, remaining hosts will discard the packet because destination ip is host B's ip address. Now host B will understand the situation and will send its mac address to directly to the host E with source address as its(host B) own ip and mac address and destination address as host E ip and mac address. Remember host E broadcasted the packet but host B Unicast the packet to host E. Now host E's ARP table is updated with ip and mac addresses. Now host E will send the packet to host B as First situation discussed earlier