I have a data center on the cisco campus that has well over 80 subnets in it, using L3 routing and no vlans on the 6509 gateways(routers)..
We also have a production data center that uses 6509's with vlans that span different areas in the data center...due to the application structure of the servers and the fact that a lot of the servers have a need for redundant nics ... It works both ways folks...depends on what the need is.... Larry Letterman Network Engineer Cisco Systems ----- Original Message ----- From: "Priscilla Oppenheimer" To: Sent: Monday, February 17, 2003 10:07 PM Subject: RE: Does MLS (Layer 3 switching) require VLANs? [7:63147] > I'm loath to continue this discussion, but I do have a question for Kelly. > Why do you have a VLAN at all in your example?? Isn't a single VLAN sort of > like one hand clapping? Seriously, what role is it playing in your network? > > Of course you don't have to have VLANs to do routing/L3 switching, as you > probabaly know. But maybe there's some weird configuration gotcha, specific > to the 6509? Just curious. Thanks. > > Larry said the majority of the Cisco campus is networked with L3 switches > and not using vlans. That says a lot right there! > > Priscilla > > Kelly Cobean wrote: > > > > All, > > I'd like to add to this something that I haven't seen in > > other posts yet, > > and that is a quick look at layer2 function. I have a Catalyst > > 6509 with an > > MSFC on it. There is only *ONE* VLAN configured on the MSFC, > > however, that > > VLAN has several secondary addresses assigned to it (I know, > > not a great > > solution, but let's not go there). If I do a "show mls entry" > > on my switch, > > it is full of entries for hosts talking to hosts on the same > > VLAN. My > > point? When a host wants to talk to a host on another subnet > > (VLAN or not), > > it ANDs the address with it's own mask, determines that the > > host is in fact > > on a different subnet, then arps (if necessary) for it's > > default gateway > > (the MSFC) and sends the packet on it's way. The 6509/MSFC > > receive the > > packet and begin the MLS cache setup process (candidate packet, > > timeout, > > etc). All this is still done inspite of the fact that the MSFC > > only has a > > single VLAN. > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On > > Behalf Of > > Stephen Hoover > > Sent: Monday, February 17, 2003 8:33 PM > > To: [EMAIL PROTECTED] > > Subject: Re: Does MLS (Layer 3 switching) require VLANs? > > [7:63147] > > > > > > > > ------------------------- > > > > actually it is by doing secondaries, but i would highly > > recommend doing > > > > vlans if possible. keep it clean and simple. > > > > > > > > > one may also configure the physical interfaces as L3 > > interfaces - just as > > > one might do on a router with several ethernet ports. > > > > > > Oooooo ok, now THAT statement leads me to believe the L3 > > switching IS > > possible without VLANs. > > > > > > -Stephen [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=63241&t=63147 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
