Cisco Cisco ASA for Nexus 1000V Series Switch 기술 매뉴얼
Network Diagram
Configurations
OSPF Support for Fast Hellos
OSPF hello packets are packets that an OSPF process sends to its OSPF neighbors in order to maintain
connectivity with those neighbors. These hello packets are sent at a configurable interval (in seconds). The
defaults are 10 seconds for an Ethernet link and 30 seconds for a non−broadcast link. Hello packets include a
list of all neighbors for which a hello packet has been received within the dead interval. The dead interval is
also a configurable interval (in seconds) and defaults to four times the value of the hello interval. The value of
all hello intervals must be the same within a network. Likewise, the value of all dead intervals must be the
same within a network.
connectivity with those neighbors. These hello packets are sent at a configurable interval (in seconds). The
defaults are 10 seconds for an Ethernet link and 30 seconds for a non−broadcast link. Hello packets include a
list of all neighbors for which a hello packet has been received within the dead interval. The dead interval is
also a configurable interval (in seconds) and defaults to four times the value of the hello interval. The value of
all hello intervals must be the same within a network. Likewise, the value of all dead intervals must be the
same within a network.
OSPF fast hello packets refer to hello packets that are sent at intervals of less than 1 second. In order to enable
OSPF fast hello packets, enter the ospf dead−interval command. For sub−second hellos, the dead interval is
set to 1 second or minimal and the hello−multiplier value is set to the number of hello packets you want sent
in that 1 second. For example, if the dead interval is set for 1 second, and the hello−multiplier is set for 4,
hellos will be sent every 0.25 seconds.
OSPF fast hello packets, enter the ospf dead−interval command. For sub−second hellos, the dead interval is
set to 1 second or minimal and the hello−multiplier value is set to the number of hello packets you want sent
in that 1 second. For example, if the dead interval is set for 1 second, and the hello−multiplier is set for 4,
hellos will be sent every 0.25 seconds.
When fast hello packets are configured on the interface, the hello interval advertised in the hello packets that
are sent out this interface is set to 0. The hello interval in the hello packets received over this interface is
ignored. It is important to note that the the dead interval must be consistent on a segment. Whether it is set to
1 second (for fast hello packets) or set to any other value, it must be consistent across neighbors in that
segment. The hello multiplier need not be the same for the entire segment as long as at least one hello packet
is sent within the dead interval.
are sent out this interface is set to 0. The hello interval in the hello packets received over this interface is
ignored. It is important to note that the the dead interval must be consistent on a segment. Whether it is set to
1 second (for fast hello packets) or set to any other value, it must be consistent across neighbors in that
segment. The hello multiplier need not be the same for the entire segment as long as at least one hello packet
is sent within the dead interval.
In order to enable fast hellos with a multiple of 4, enter the ospf dead−interval minimal hello−multiplier
4 command under the appropriate interface configuration.
4 command under the appropriate interface configuration.
interface GigabitEthernet0/0
nameif inside
security−level 100
ip address 198.51.100.1 255.255.255.0
ospf dead−interval minimal hello−multiplier 4
router ospf 1
network 198.51.100.0 255.255.255.0 area 0
Verify with the show ospf interface command.