IP Address vs MAC addresses

Question

why do we need ip addresses if mac address is enough to identify the machine???

Solution 1

IP addresses are hierarchical, so that routers throughout the internet know which direction to forward a packet. With MAC addresses, there is no hierarchy, and thus packet forwarding would not be possible.

Solution 2

From MAC Address vs IP Address

When the packet is being sent out to a statipn that is on the same network LAN segment, only the MAC address is needed. When the packet goes beyond, to different networks and travels through routers, the MAC address is still contained in the packet, but only the IP address is used by the routers.

Also from What's the difference between a Mac Address and an IP Address?

MAC addresses aren't part of the discussion, simply because they never travel beyond your local network, and they can't be hidden as they're simply required for networking to work.

Solution 3

There are many reasons. For example: MAC address is bound to hardware. It means you can't or rather are not supposed to have the same MAC on different hardware. Imagine that google has to change DNS binding of "google.com" to "MAC" address each time they change some network card on front-end server.

Another reason is that MAC addresses are assigned by producers while IP addresses are assigned by network admins. This allows building hierarchy of addresses that is root of packets routing. This is because way from IP A1.A2.A3.A4 to B1.B2.B3.B4 is easily predictable and way from MAC#1 to MAC#2 isn't.

Next reason is that MAC is Ethernet-related stuff and there are other network technologies that might not use MAC at all.

Solution 4

Sometimes we don't want to identify the machine. One machine can have two IP's, IP's can represent things that aren't machines, the list of reasons goes on and on, I'm sure others will come up with some better ones.

Solution 5

IP - means Internet Protocol which is used to communicate between Inter Connected Networks (Internet = Inter Connected Networks OR Group of Diffrent-2 Networks Connected together )

MAC - means Media Access Control , which is used to communicate in a SINGLE Network OR in Same Network ( Network = Group of 2 or more hosts )

IP Addresses are systematically distributed worldwide by IANA (Internet Assigned Number authority ) , So that END-TO-END Locations can be easily Find out by routers ****** BUT ***** MAC Addresses are not Distributed Systematically ....Because MAC Addresses are assigned to your LAN card when it is Manufactured by some vendors. It is than Shipped and placed in random computers around the world

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Comments

[Admin]

why do we need street addresses if ADN secuence is enough to identify a person? In a similar way, this question mix the levels of abstraction and function for both numbers.

[llewellyndave]

not necessarily, there are cards on which you can change the mac-address (not consumer cards ofcourse ;) ). Ip changes only if you use dhcp. In data centers, for example, they might be statically configured.

[Admin]

It's worth noting that these are fundamental different layers in a network model as well. IP addresses deal with the network layer. mac addresses deals with the link layer(and a link layer is usualyl point-to-point). see e.g. en.wikipedia.org/wiki/OSI_model

[llewellyndave]

Just illustrating a situation where they do change

[Martin Konecny]

Because a MAC address is assigned to your network card when it is manufactured. It is then shipped and placed in random computers around the world, and thus no hierarchy :). IP addresses are assigned when you connect to your ISP, and so a hierarchy is maintained.