810
Configuring IP Unicast Routing
Configuring IP Addressing
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.
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. The switch
supports several addressing schemes for forwarding broadcast messages.
Enabling Directed Broadcast-to-Physical Broadcast Translation, page 810
Forwarding UDP Broadcast Packets and Protocols, page 812
Establishing an IP Broadcast Address, page 813
Flooding IP Broadcasts, page 813
Enabling Directed Broadcast-to-Physical Broadcast Translation
By default, IP-directed broadcasts are not forwarded; they are dropped to make routers less susceptible to
denial-of-service attacks. You can enable forwarding of IP-directed broadcasts on an interface where the broadcast
becomes a physical (MAC-layer) broadcast. Only those protocols configured by using the
ip forward-protocol
global
configuration command are forwarded.
BEFORE YOU BEGIN
You can specify an access list to control which broadcasts are forwarded. Only those IP packets permitted by the access
list are eligible to be translated from directed broadcasts to physical broadcasts.
Содержание IE 4000
Страница 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Страница 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Страница 108: ...104 Configuring Switch Clusters Additional References ...
Страница 128: ...124 Performing Switch Administration Additional References ...
Страница 130: ...126 Configuring PTP ...
Страница 140: ...136 Configuring CIP Additional References ...
Страница 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Страница 192: ...188 Configuring Switch Based Authentication Additional References ...
Страница 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Страница 274: ...270 Configuring SGT Exchange Protocol over TCP SXP and Layer 3 Transport Configuring Cisco TrustSec Caching ...
Страница 298: ...294 Configuring VLANs Additional References ...
Страница 336: ...332 Configuring STP Additional References ...
Страница 408: ...404 Configuring DHCP Additional References ...
Страница 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Страница 490: ...486 Configuring SPAN and RSPAN Additional References ...
Страница 502: ...498 Configuring Layer 2 NAT ...
Страница 559: ...555 Configuring Network Security with ACLs How to Configure Network Security with ACLs Creating a Numbered Extended ACL ...
Страница 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Страница 930: ...926 Configuring IP Unicast Routing Related Documents ...
Страница 956: ...952 Configuring IPv6 Unicast Routing Configuring IPv6 network 2010 AB8 2 48 network 2010 AB8 3 48 exit address family ...
Страница 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Страница 978: ...974 Dying Gasp ...
Страница 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Страница 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Страница 996: ...992 Ethernet CFM ...
Страница 1030: ...1026 Working with the Cisco IOS File System Configuration Files and Software Images Working with Software Images ...
Страница 1066: ...1062 Using an SD Card SD Card Alarms ...