- Alcatel Switch/Router User Manual

Creating a New Group
Page 19-31
4) Flood Limit
The flood limit allows you to tune a virtual port to limit the flooding of broadcast, multi-
cast, and unknown destination packets. This feature is useful for controlling broadcast
storms on your network. While each network is different, in general the amount of
flooded traffic represents a relatively small percentage of network traffic.
The flood limit is actually a “transmit credit” that is issued every five (5) seconds. When a
packet is flooded on this port, the size of the packet, in bytes, is decremented from the
current credit value. The credit value is the value you enter in this field multiplied by five.
An additional credit, in the amount of the value you enter here multiplied by five, is allo-
cated to each virtual port every five (5) seconds. If the credit value ever falls below zero,
then all flooded packets are discarded until another credit is allocated. Flood limit check-
ing is disabled if you enter a flood limit of zero (0). The flood limit default is 192,000
bytes per second, which equates to a transmit credit of 960,000 bytes every five seconds.
5) Output Format Type
The output format setting determines the kind of frame that will be sent out this physical
port. If translation is necessary, then incoming frames will be translated to this format
before being sent out this port. For example, on an Ethernet port incoming
FDDI frames
need to be translated to Ethernet. However, there are four types of Ethernet frames—
Ethernet II, IPX 802.3, SNAP, and LLC. The format type you select here would determine
the frame format to which non-Ethernet frames would be translated. The following figure
illustrates how a port’s framing type affects communication with attached devices.
♦ Note ♦
This parameter differs from the router framing type
selected during the configuration of the virtual router
port. The router framing type is the encapsulation done
on a router port, whereas this output format type
applies only to translations on this virtual port.