Steven Aiello wrote: > > Hello all, > > I need some folks with hopefully a CCIE to answer this > question. > > If there is an un subnetted class A, and there are 25 or users > on the > network. would the fact that the network is unsubnetted cause > a large > load of network traffic? > > here is the reason and layout. > > Our company uses Xerox printers and they came with address > > 10.6.1.45 - 255.0.0.0 > 10.6.1.44 - 255.0.0.0 > > our clients are all on the same network using a DHCP pool of > > 10.6.1.100 - 10.6.1.150 > > even if there is broadcast it is one message across the > network (lets > say for Netbios name resolution) there is one broadcast not a > unicast to > 16,7xx,xxx some host.
True. It will just be one broadcast packet and probably won't use a lot of bandwidth. It may be repeated a few times, but probably still won't use a lot of bandwidth. >Only 25 hosts will answer correct? They won't all answer, just the one with the name that needs to be resolved. A lot of NetBIOS naming traffic is hosts announcing their own names actually. Nobody answers those. The issue isn't whether they answer or not anyway. Nor is it a bandwidth consumption issue, as you realize. It's an issue of eating CPU cycles on the hosts and NICs that receive the broadcast, which could be as many as 16,777,000 hosts with your current addressing scheme. Every NIC and host has to take in the packet, process it, and probably discard it, but still that could represent a significant amount of work. Your consultant is probably concerned that all devices are in the same broadcast domain. They all hear each other's broadcasts. If they are all announcing their names and trying to find each other by name and ARPing and RIPing and DHCPing, etc., this could become a performance issue on the hosts. Of course, you don't have nearly 16 million devices (25 you say?) so it's not an issue yet. Cisco recommends no more than 500 nodes per broadcast domain so you're pretty safe. The printers are going to broadcast at a particular rate regardless of the subnet mask. The packets they send probably aren't very big. They probably aren't using a lot of bandwidth But if you subdivided the network into multiple subnets and broadcast domains, using routers, not as many hosts will hear the broadcasts. The problem with broadcasts usually isn't a bandwidth consumption issue. It's a problem with the fact that a broadcast interrupts the CPU of every station in the broadcast domain. A lot of broadcasts can noticeably slow down an already slow computer with an old CPU. Nowadays, it would probably be a lot harder to cause a noticeable difference, CPUs are so fast. Anyway, your consultant may not be dumb, but she or he didn't describe the issue very well. Broadcast domains are covered in CCNA material, by the way. This isn't CCIE stuff. :-) Priscilla > NetBSo > how will a > class A subnet mask cause this? > > Thanks for all input, please feel free to ramble, > Steve > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=75219&t=75213 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
