?– Large amount of unknown MAC unicast traf?¬?c: Cisco Catalyst switches limit
unicast frame forwarding to ports that are associated with the speci?¬?c unicast address.
However, when frames arrive at a destination MAC address that is not recorded in the
MAC table, they are ?¬‚ooded out of the switch ports in the same VLAN except for the
port that received the frame. This behavior is called unknown MAC unicast ?¬‚ooding.
Because this type of ?¬‚ooding causes excessive traf?¬?c on all the switch ports, network
interface cards (NIC) must contend with a larger number of frames on the wire. When
data is propagated on a wire for which it was not intended, security can be compromised.
?– Multicast traf?¬?c on ports where it is not intended: IP multicast is a technique that
allows IP traf?¬?c to be propagated from one source to a multicast group that is identi?¬?ed
by a single IP and MAC destination-group address pair. Similar to unicast ?¬‚ooding and
broadcasting, multicast frames are ?¬‚ooded out all the switch ports. A proper design
allows for the containment of multicast frames while allowing them to be functional.
?– Dif?¬?culty in management and support: A poorly designed network may be
disorganized and poorly documented and lack easily identi?¬?ed traf?¬?c ?¬‚ows, which can
make support, maintenance, and problem resolution time-consuming and arduous tasks.
Pages:
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46