On our controllers (WiSM 4.0.219.0) broadcast and multicast were off by default.
I was initially concerned about the large broadcast domain of a 21 bit subnet but was pleasantly surprised to see the traffic was being suppressed. I did some digging around and I *believe* this is controller by the "Ethernet Multicast Mode" setting in the web gui of the controller. We have this set to "disabled". I just did a quick search on Cisco.com and found this document: http://tinyurl.com/2e4lml It states that before firmware 4.0.206 that multicast packet forwarding also enabled broadcast packets. However firmwares 4.0.206 and later can use the "config network broadcast enable/disable" from the CLI to enable or disable broadcast traffic. Hope this helps, Walt -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of David Blahut Sent: Thursday, April 24, 2008 1:47 PM To: [email protected] Subject: Re: [WIRELESS-LAN] Question on layer 3 size Walt, Can you elaborate on how you disabled broadcast and multicast packets on your wireless VLANS. Thanks, David Howd, Walt wrote: > With our Cisco WiSM we run a 21 bit mask VLAN for students and a second > 21 bit mask VLAN for faculty/staff using VLAN assignment. > > In our setup, multicast and broadcast packets are disabled on the > wireless VLANS so the large size is not an issue. > > This was actually a nice feature of the controller. Broadcast traffic > that needs to work (ARP, etc) gets answered by the controller and > everything else (windows file sharing, etc) gets dropped. We don't have > any applications that we support on wireless that require broadcast or > multicast so this was an easy choice. > > Walt > > -----Original Message----- > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > [mailto:[EMAIL PROTECTED] On Behalf Of Jim Glassford > Sent: Thursday, April 24, 2008 8:58 AM > To: [email protected] > Subject: [WIRELESS-LAN] Question on layer 3 size > > Greetings, > > Cisco 4402 and 4404 Wireless Lan Controllers with a mixer of Cisco > light > weight access points. Currently running a 22 bit mask for the 1022 hosts > on > one SSID/VLAN. Would welcome any real world experience about increasing > to a > 21 bit mask for the 2046 hosts or larger on one SSID/VLAN with Cisco > WLCs > and lwaps. > > Thanks! > jim > > ********** > Participation and subscription information for this EDUCAUSE Constituent > Group discussion list can be found at http://www.educause.edu/groups/. > > ********** > Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. > ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
