Matthew Petach wrote:
As I understand it, (and Cisco's documentation seems to support this, http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2ZY/command... as an example), if you put a /128 in an ACL, you cannot specify any L4 port information for the address due to the limited width of the TCAM; in order to specify L4 information for the ACL, Cisco stuffs it into bits 24 through 39, losing what information was originally stored in those bits. It just so happens those are the fixed FFFE bits in an EUI-64 address, so if you're using EUI-64, no "real" information is lost. You can do your own non-EUI-64 addressing and still use ACLs with layer 4 port information as long as you don't put any addressing information into bits 24 through 39.
Interesting; makes sense though. Thanks for the explanation. ~Seth