Priscilla, Never fear, I and many others I think, consider any discussion you're a part of a MUST READ! So feel free to ......zzzzzzzzzzzzzzzzzzzz
Prof. Tom Lisa, CCAI Community College of Southern Nevada Cisco Regional Networking Academy Priscilla Oppenheimer wrote: > Well, now you're really talking about the dark ages. ;-) > > You are back to the early 1990s discussion about upgrading hubs to > switches. That's a good idea so that each port has 100 Mbps (or 10 Mbps) > rather than all ports sharing bandwidth and being in the same collision > domain. I can't think of any reason not to upgrade to switches at this > point. It's difficult to even buy a 100-Mbps hub any more. (I tried and > they sent me a switch!) The upgrade is quite seamless (unlike the upgrade > from switches to VLAN-aware switches.) > > This has nothing to do with the late 1990s question of broadcasts which > came about when people started replacing routers with switches and > designing a network that was a large broadcast domain. They thought they > had solved all their problems but they hadn't because a switch forwards > broadcasts, whereas a router does not, of course. > > VLANs let you divide up those broadcast domains and be smarter about the > flooding of unknown unicasts (as someone else mentioned, which was a good > point.) > > But VLANs bring with them all sorts of other management headaches. It's a > tradeoff that doesn't need to be made in many modern networks, despite what > Cisco tells you. The materials that we read about broadcasts in switched > networks come from studies Cisco did in 1994. And some books still have > that silly triangle that a Cisco marketing engineer (now that's an > oxymoron!) designed in 1994. > > Yes, I know that VLANs have other advantages (supposedly) besides dividing > up broadcast domains, and I warned people up front that my point of view > was controversial, but I'm sticking to it. ;-) > > With regards to your practical limits, Cisco has some guidelines (but once > again they are based on OLD data ;-) A broadcast domain shouldn't have more > than a few hundred nodes. > > Also, with regards to your comment about sniffing on a switched network. > Remember that all you see is broadcasts and traffic to your port (unless > you mirror other ports) so you get a skewed view. > > So have we beat this one to death yet? I enjoyed the discussion. (I hope we > didn't put everyone else to sleep! ;-) > > Priscilla Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=24174&t=23950 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
