Alcatel Carrier Internetworking Solutions Switch/Router 사용자 설명서
AutoTracker VLANs
Page 22-15
Frame Flooding in AutoTracker VLANs
Flooding occurs when a frame is received addressed to a device that is unknown to the
switch or broadcast or multicast frames are received addressed to multiple users. In a typical
bridged environment, the frame would be forwarded out all ports. However, this is not true
with
switch or broadcast or multicast frames are received addressed to multiple users. In a typical
bridged environment, the frame would be forwarded out all ports. However, this is not true
with
VLAN
s as
VLAN
s segment the network into smaller broadcast domains. In this environ-
ment, flooding occurs as follows:
Unicast Traffic
• If the destination address of the frame is unknown buts its source address is known and
the source device is a member of one or more
VLANs
, the frame is flooded out all ports of
all
VLANs
in which the source device is a member. Please note the following:
–
If the source device is a member of multiple
VLANs
, some leakage may occur during
the flooding process. Leakage may occur only among
VLANs
in the same Group—
frames do not leak between Groups.
–
If the source device is a member of multiple
VLANs
and some or all of those
VLANs
share the same physical port, only one copy of the frame is forwarded out that port.
–
If the source device is a member of multiple
VLANs
that use trunking, only one copy
of the frame is sent to each trunk port.
• If both the source and destination addresses of the frame are unknown, the frame is
forwarded to the
MPX
for processing (to determine the
VLAN
or
VLANs
in which the origi-
nating device should be a member) and the frame is flooded out all ports of all
VLANs
in
which the source port is a member.
Broadcast and Multicast Traffic
Frames are forwarded out all ports that are members of the same
VLAN
s as the source
MAC
address. If the source
MAC
address is unknown, it is forwarded out all ports that have
VLAN
s
active on the source ports.
Routing Between AutoTracker VLANs
Devices that do not share membership in a common
VLAN
must use routers to communicate
with one another. You can configure a virtual router port that is capable of
IP
and/or
IPX
routing for each
VLAN
. By enabling a router port on a
VLAN
, you are creating a static route
entry within the switch to that
VLAN
. If this router port is not configured for a
VLAN
, then that
VLAN
will not be able to communicate with other
VLAN
s unless an external router is between
those
VLAN
s. You may configure up to 16 virtual router ports within a single Omni Switch/
Router. Each
VLAN
may contain only one router port.
Routing and the Default VLAN
. You can enable routing for the default
VLAN
when you initially
create a Group, or when you modify the Group. There are several issues about which you
should be aware when enabling routing on the Default
should be aware when enabling routing on the Default
VLAN
. See Application Example 4 in
Chapter 24, “AutoTracker VLAN Application Examples,” for more information.