Bikespace, Just spent a day testing exactly this...spooky You're correct , Cisco's cannot put a multicast mac in its arp cache dynamically - BUT - you CAN put STATIC ARP entries in a Cisco pointing to a multicast mac.( Even if Layer3 is unicast)
However there are some small perfomance points here ( only small !) Turning CEF on does have some benefits but not huge amounts. I threw 100 * 512 byte UPD segments at the Cisco for 5 mins while using a static multicast arp entry - It coped just fine. HTH Rich Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=69993&t=69505 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]

