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Eus
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Hi Ho!
On page 322 of Computer Network: A Top-Down Approach Featuring the Internet, 2nd Edition by Kurose and Ross, which is published by Addison-Wesley, it is stated that:
"Because every host and router is capable of sending and receiving IP datagrams, IP requires each host and router interface to have its own IP address. Thus, an IP address is technically associated with an interface, rather than with the host or router containing that interface."
Is it true that the reason why IP requires each host and router interface to have its own IP address is because every host and router is capable of sending and receiving IP datagrams?
If suppose an IP address is technically associated with the host or router containing that interface, will this eliminate the capability of sending and receiving IP datagrams of every host and router? Of course not, but this reduces the role of the router to just merely a hub. Suppose a router has more than one interface, all of which has the same IP address, which is the IP address of the router. Then, whenever the router wants to route a datagram, the routing table that the router consults will show the same IP address for each interface through which it should forward the datagram. Therefore, the router will simply forward the datagram to all of the interfaces; it acts just like a hub.
It can be argued that, since an IP address is not technically associated with an interface anymore, the routing table should store the code of each interface so that the router can forward the datagram through the right interface. This way the router can act as a router instead of a hub. However, the router will never be able to interconnect two or more different networks that have different netmasks. For example, one network has a network number 103.0.0.0 and a netmask 255.0.0.0. The other network has a network number 200.233.31.0 and a netmask 255.255.255.0. If the router has a network number of 103.0.0.0, datagrams from the second network will never reach the router, and vice versa.
Therefore, the main reason to associate an IP address with each interface is to permit a router to interconnect two or more different networks with different network numbers, not because every host and router is capable of sending and receiving IP datagrams.
What do you think?
Eus
On page 322 of Computer Network: A Top-Down Approach Featuring the Internet, 2nd Edition by Kurose and Ross, which is published by Addison-Wesley, it is stated that:
"Because every host and router is capable of sending and receiving IP datagrams, IP requires each host and router interface to have its own IP address. Thus, an IP address is technically associated with an interface, rather than with the host or router containing that interface."
Is it true that the reason why IP requires each host and router interface to have its own IP address is because every host and router is capable of sending and receiving IP datagrams?
If suppose an IP address is technically associated with the host or router containing that interface, will this eliminate the capability of sending and receiving IP datagrams of every host and router? Of course not, but this reduces the role of the router to just merely a hub. Suppose a router has more than one interface, all of which has the same IP address, which is the IP address of the router. Then, whenever the router wants to route a datagram, the routing table that the router consults will show the same IP address for each interface through which it should forward the datagram. Therefore, the router will simply forward the datagram to all of the interfaces; it acts just like a hub.
It can be argued that, since an IP address is not technically associated with an interface anymore, the routing table should store the code of each interface so that the router can forward the datagram through the right interface. This way the router can act as a router instead of a hub. However, the router will never be able to interconnect two or more different networks that have different netmasks. For example, one network has a network number 103.0.0.0 and a netmask 255.0.0.0. The other network has a network number 200.233.31.0 and a netmask 255.255.255.0. If the router has a network number of 103.0.0.0, datagrams from the second network will never reach the router, and vice versa.
Therefore, the main reason to associate an IP address with each interface is to permit a router to interconnect two or more different networks with different network numbers, not because every host and router is capable of sending and receiving IP datagrams.
What do you think?
Eus