Stephen Hoover wrote: > > Ok, let me see if I can simply this: > > A post that Jens Neelsen made says "a layer3 switch > (e.g.3550-EMI) does not > have layer3 interfaces. All interfaces (Fastethernet and > GigabitEthernet) > are layer2 > interfaces. They can not have IP addresses."
He was just trying to get you to see that a L3 switch can have many interfaces that are L2 interfaces. > Further he adds > "The VLANs are > the (virtual) interfaces to the routing engine (=layer3 > switch). Layer2 > interfaces are grouped into different VLANs and the Layer3 > switch (=Router) > enables the communications between these VLANs. " > > Ok then the question is - if you have a LAN with ALL switches > and NO > routers - how do you define a gateway on the client? You don't. Gateway just means router (L3 switch). There used to be lots of LANs with no routers in the old days. You think the terminology is confusing these days; it was worse years ago. People used the term gateway to mean router. The term "default gateway" comes from that. So your question doesn't make sense. You said if you have a LAN with all switches and no routers, how do you define the router? WHY would you want to? There is no router. > > Example: > > 2 L2 switches. All hosts on switch 1 are in IP subnet > 192.168.1.0/24 and all > hosts on switch 2 are in IP subnet 192.168.2.0/24. Both L2 > switches are > connected to a single L3 switch with a router engine in it. Oh, you DO have a router (L3 switch). I thought you said that there were no routers. > > Where do you define the gateways at? The router (L3 switch) is the gateway. It's not clear from your question if all hosts are connected to a single interface on the router or if you have more than one interface. But the default gateway (router/L3 switch) is the interface that they connect to. > In order for hosts on L2 > switch 1 to > communicate with hosts L2 switch 2, the client has to have a > gateway to > forward to correct?? > > Stephen > > > > ----- Original Message ----- > From: "Priscilla Oppenheimer" > To: > Sent: Monday, February 17, 2003 4:45 PM > Subject: RE: Understanding VLANs - how they remove the physical > [7:63173] > > > > Stephen Hoover wrote: > > > > > > back to switch A to get his routing to > > > the servers? > > > Why would you EVER want a network configured this way?? Or > even > > > worse, what > > > if your respective gateway was 3 or 4 L3 switches away? > > > > Your gateway can't be any L3 switches (routers) away. It has > to be on your > > LAN. It has to be in your subnet. It has to be in your > broadcast domain. > It > > has to be in your VLAN. For one thing, a host ARPs for its > default > gateway. > > ARP uses broadcast. > > > > I just noticed your comment and wanted to add my comment. > Without being > able > > to decode your drawing, it's hard to tell exactly how to > answer, but I'm > > just trying to get you to think about what really happens to > packets on a > > campus network. The network design you're considering isn't > just > > impractical. It won't work, if I understand it correctly. > > > > Priscilla > > > > > > > > > That > > > just doesn't > > > seem practical to me. > > > > > > > > > Thanks! > > > Stephen Hoover > > > Dallas, Texas > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=63200&t=63194 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
