IP address and Gateway are same?

[zillah2004]

Hi All

When I accessed the dial upo internet and when I checked the IP address I found these detaisl ipconfig:

IP: 220.165.165.7

SubentMask: 255.255.255.255

Gateway: 220.165.165.7

1- Can the IP address be similar to gateway?

2- Can subnetmask be as broadcast address?

[zillah2004]

I like these type of discission because, it concretes many fundemntal concepts

You said :"Well, I figure it must be the original target IP". look at

Cisco Curriculum CCNA1 V3.1 Section 9.3.7:

"Since this router has ARP proxy enabled, it prepares an ARP reply to the requesting host with its MAC address and the IP address of the destination device".

[zillah2004]

Recall to your first reply

You said:

"This has two different implications, depending on whether you are on a multiaccess network or a single link."

1- Did you mean by "single link" as point-to-point access (dedicated link)?. And did you mean by "multiaccess network";as shared link (multiple access which can involve point-to-point access)?

You said:

"If you are on a point-to-point network and you are your own gateway, and you want to send a packet to any destination, then you just send the packet on the wire. The packet will be routed by whatever is at the other end of the wire."

2- How can I be my own gateway,, I did not get what did you mean? Could you please explain more?

May be first point will make second point clear!

[Kevin Dorrell]

Yes, by "single link", I did mean point-to-point.

By "be my own gateway", I mean that I have a default gateway adress configured equal to my own IP address.

HTH

Kevin Dorrell

Luxembourg

[zillah2004]

1-My understanding that point-to-point can be on single link and shared link,,,Now you meant by single link dedicated link,,,,did not you?

2-In reality can the PC be its own gateway special with ISP?

[zillah2004]

Any help about this topic

[olorunloba]

With respect to a shared link, this is a link capable of having more than 2 devices on it. A common example of this is the ethernet segment. In this shared medium, the sending devices need a way fo knowing the mac address of their recipient. On an ethernet segment, ARP is used to learn the mac address. The switches on the ethernet segment can then efficiently deliver the packet. More importantly, the recipient devices can also check and confirm that the packet is meant for him, as the frame could be destined for another device on the segment.

On a point to point, it is assumed that any traffic recieved is meant for him, as there can be only two devices. In this instances, such as when you have a PPP dial up (or PPPoE) to your service provider, the system is configured to have his ip address as the gateway, which translate to him pushing all the frame on the line. When the router at the other end recieves the frame, it is properly routed.

Note this scheme conserves ip address

[zillah2004]

Thanks

[zillah2004]

Thanks olorunloba

1- You said: "With respect to a shared link, this is a link capable of having more than 2 devices on it. A common example of this is the ethernet segment."

You meant here LAN, Did not you? Because you mentioned "The switches on the ethernet segment can then efficiently deliver the packet".

2- You said: "On a point to point, it is assumed that any traffic recieved is meant for him, as there can be only two devices. In this instances, such as when you have a PPP dial up (or PPPoE) to your service provider"

2/A- If it is point-to-point within dedicated link (only two devices, real point-to-point) then we can consider what you said: "it is assumed that any traffic recieved is meant for him"

2/B- If it is shared link (more than one pair within shared line, logical point-to-point,and this is case of all ISPs), then how can we consider : "it is assumed that any traffic recieved is meant for him"???!!!

Thanks

[olorunloba]

Hmm, quite a dribble of scenarios.

When you have a logical point to point on a shared access medium, (very good example is the PPPoE), it can still be assumed that any traffic meant for him.

Why?

Traffic flows out throught the virtual point-to-point interface. On this virtual interface, there exist only two devices, and the virtual interface is entirely not aware of the shared infrastructure.

When a PPPoE connection is made, a niew virtual PPP adapter is assigned an ip address. The ethernet interface itself does not carry any ip address. This pushes the traffic out through the virtual interface.

Hope this explanation helps.

[zillah2004]

Thanks olorunloba, really it is very good explination.

Now could you please comment my first query also.

Thanks

[olorunloba]

I assume you are refering to the shared medium. Ethernet is a common example of shared medium, but there are others such as ATM and FDDI

[zillah2004]

I am refering to this :

"You meant here LAN, Did not you? Because you mentioned "The switches on the ethernet segment can then efficiently deliver the packet".