thats pris's job here....if she writes enough detailed answers we dont have to buy her books...:)
Larry Letterman Network Engineer San Jose Transport Cisco Systems Inc. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Tamhankar, Nitin > Sent: Thursday, January 09, 2003 11:18 AM > To: [EMAIL PROTECTED] > Subject: RE: Subnet question [7:60711] > > > Thank you very much for taking pains to right such a detailed explanation. > Thank you all for your answers they were very helpful. > > Thanks > Nitin > > -----Original Message----- > From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] > Sent: Thursday, January 09, 2003 12:36 PM > To: [EMAIL PROTECTED] > Subject: RE: Subnet question [7:60711] > > > You may not need virtual LANs. Real LANs solve the problem. :-) This is a > classic case of subnetting. > > With DHCP, the client should get the right address when it > broadcasts after > it moves, so there's no issue. > > Leaving DHCP out of the picture, the need to ensure that a moved > node can't > communicate is met simply by the way IP works. > > Assume there's a client with this config: > > address = 100.10.1.100 > subnet mask = 255.255.255.0 > default gateway = 100.10.1.1 > > Assume the client is physically sitting on the 100.10.2.0/24 network. When > it wants to send to nodes on the 100.10.1.0 network, it will compare its > address with the destination address, assume it's on the same subnet, and > send an ARP broadcast. The ARP broadcast won't reach the > destination though, > which is on a different LAN, so it won't work. > > (Make sure the router isn't configured for Proxy ARP. But even with Proxy > ARP, communication won't work. With Proxy ARP, the router could respond on > behalf of the destination on the 100.10.1.0 network. However that host > wouldn't be able to respond because it would assume that 100.10.1.1 is > local.) > > Assume the client wishes to reach devices on the 100.10.2.0 or 100.10.3.0 > network. It will compare its address with the destination address > and decide > that it's not on the same subnet, so it needs to send to the default > gateway. It will send a broadcast for the default gateway, which > won't work > because 10.10.1.1 is on a different LAN. Once again make sure Proxy ARP is > disabled. I'll leave it to the reader to figure out what would happen in > this case if Proxy ARP were enabled. :-) > > The question of VLANs versus real LANs requires more info. How many router > ports to you have? Is each router port a subnet? Or do you plan to have > multiple subnets out one router port, in which case you need VLANs and > inter-VLAN routing on the router. > > _______________________________ > > Priscilla Oppenheimer > www.troubleshootingnetworks.com > www.priscilla.com > > Nathan Nakao wrote: > > > > I'd probably use VLAN's. > > > > Conf t > > Int vlan 101 > > Int vlan 102 > > Int vlan 103 > > > > Then setup the DHCP to assign IP addresses accordingly. > > > > Once that is done. Set the vlans to 101 for first floor, 102 > > for second > > floor, and 103 for third floor. > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On > > Behalf Of > > Tamhankar, Nitin > > Sent: Thursday, January 09, 2003 8:40 AM > > To: [EMAIL PROTECTED] > > Subject: Subnet question [7:60711] > > > > > > This might be a very elementary question for some of you guys > > but I > > would appreciate the answer. > > > > If an office which has 3 different floors and has Cisco routers > > and > > catalyst switches and windows environment. We need to configure > > it in > > such a way that each floor is on its own subnet for example > > > > floor1 100.10.1.0 > > floor2 100.10.2.0 > > floor3 100.10.3.0 > > > > Also if a computer which has IP address in subnet 100.10.1.0 is > > moved > > from floor 1 to floor 2, it should not communicate with the > > network > > unless its IP address is changed to one in 100.10.2.0 subnet. > > > > How it can be accomplished? > > > > Thank you > > Nitin > > > > [GroupStudy.com removed an attachment of type > > application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=60772&t=60711 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
