40-14
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-08
Chapter 40 Configuring IP Unicast Routing
Configuring IP Addressing
If you change the
maxadvertinterval
value, the
holdtime
and
minadvertinterval
values also change,
so it is important to first change the
maxadvertinterval
value, before manually changing either the
holdtime
or
minadvertinterval
values.
Use the
no ip irdp
interface configuration command to disable IRDP routing.
Configuring Broadcast Packet Handling
After configuring an IP interface address, you can enable routing and configure one or more routing
protocols, or you can configure the way the switch responds to network broadcasts. A broadcast is a data
packet destined for all hosts on a physical network. The switch supports two kinds of broadcasting:
•
A directed broadcast packet is sent to a specific network or series of networks. A directed broadcast
address includes the network or subnet fields.
•
A flooded broadcast packet is sent to every network.
Note
You can also limit broadcast, unicast, and multicast traffic on Layer 2 interfaces by using the
storm-control
interface configuration command to set traffic suppression levels. For more information,
see
Chapter 26, “Configuring Port-Based Traffic Control.”
Routers provide some protection from broadcast storms by limiting their extent to the local cable.
Bridges (including intelligent bridges), because they are Layer 2 devices, forward broadcasts to all
network segments, thus propagating broadcast storms. The best solution to the broadcast storm problem
is to use a single broadcast address scheme on a network. In most modern IP implementations, you can
set the address to be used as the broadcast address. Many implementations, including the one in the
switch, support several addressing schemes for forwarding broadcast messages.
Perform the tasks in these sections to enable these schemes:
•
Enabling Directed Broadcast-to-Physical Broadcast Translation, page 40-15
•
Forwarding UDP Broadcast Packets and Protocols, page 40-16
•
Establishing an IP Broadcast Address, page 40-17
•
Flooding IP Broadcasts, page 40-17
Step 6
ip irdp maxadvertinterval
seconds
(Optional) Set the IRDP maximum interval between advertisements. The
default is 600 seconds.
Step 7
ip irdp minadvertinterval
seconds
(Optional) Set the IRDP minimum interval between advertisements. The
default is 0.75 times the
maxadvertinterval
. If you change the
maxadvertinterval
, this value changes to the new default (0.75 of
maxadvertinterval
).
Step 8
ip irdp preference
number
(Optional) Set a device IRDP preference level. The allowed range is –2
31
to 2
31
. The default is 0. A higher value increases the router preference
level.
Step 9
ip irdp address
address
[
number
]
(Optional) Specify an IRDP address and preference to proxy-advertise.
Step 10
end
Return to privileged EXEC mode.
Step 11
show ip irdp
Verify settings by displaying IRDP values.
Step 12
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Содержание Catalyst 3750-E Series
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