RE: Understanding VLANs - how they remove the phys [7:63196]
Emilia Lambros wrote: > > Why can't the L3 switches be run as L2 switches (ignoring the > routing capabilities) in that situation? If those two switches > were connected in that case, then connected to the core, > wouldn't that solve the problem of a gateway being 3 or 4 L3 > switches away? Your default gateway can be any number of L2 switches away from you. It just has to be in your subnet, VLAN, broadcast domain. Priscilla > > -Original Message- > From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, 18 February 2003 9:15 AM > To: [EMAIL PROTECTED] > 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=63201&t=63196 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Understanding VLANs - how they remove the phys [7:63196]
> Emilia Lambros wrote: > > > > Why can't the L3 switches be run as L2 switches (ignoring the > > routing capabilities) in that situation? If those two switches > > were connected in that case, then connected to the core, > > wouldn't that solve the problem of a gateway being 3 or 4 L3 > > switches away? > > Your default gateway can be any number of L2 switches away from you. It just > has to be in your subnet, VLAN, broadcast domain. > > Priscilla > I caused the confusion in this situation - I asked what would happen if your gateway was 3 or 4 L3 switches away. What I should have asked was what would happen if your gateway was 3 or 4 distribution layer switches away. I was referring to the L3 switches as devices instead of function. In my example I was trying to illustrate how extending a VLAN across the core created a poor path for the client on the far side. When I said that the client on the far side is a L3 switch away from it's own gateway, what I meant was that the client's network path would have to cross the L3 switch (but at the L2 level) in building B to get to it's gateway on the L3 switch in building A. In other words the host is crossing the core through the L3 switch in building, but it is crossing that L2 level. Sorry for that. > > > > > > 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. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=63217&t=63196 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Understanding VLANs - how they remove the phys [7:63196]
I'm resisting the overwhelming urge to say something like "So there's not a problem?" but the two L3/L2/Router/switch discussion are just so darned informative! I think there's a bit of a hole of confusion that I fell into the first time I consoled onto a 2950 and had to configure it. Every interface said "no ip address" and vlans could be real interfaces with IP addresses. Its around that moment that you forget they *can* still be layer 2 devices :) -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 18 February 2003 11:53 AM To: [EMAIL PROTECTED] Subject: RE: Understanding VLANs - how they remove the phys [7:63196] Emilia Lambros wrote: > > Why can't the L3 switches be run as L2 switches (ignoring the > routing capabilities) in that situation? If those two switches > were connected in that case, then connected to the core, > wouldn't that solve the problem of a gateway being 3 or 4 L3 > switches away? Your default gateway can be any number of L2 switches away from you. It just has to be in your subnet, VLAN, broadcast domain. Priscilla > > -Original Message- > From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, 18 February 2003 9:15 AM > To: [EMAIL PROTECTED] > 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=63222&t=63196 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
