Configuring Routing 553
– Timed Out—The previous graceful restart timed out.
– Topology Changed—The previous graceful restart terminated prematurely because of a topology
change.
If you change the Support Mode, click Submit to save your change.
Click Refresh to redisplay the page with the latest values from the switch.
Enabling the NSF OSPF Graceful Restart Using CLI Commands
For information about the CLI command that per forms this function, see the following chapter in the
CLI Reference Guide:
• OSPF Commands
The following table summarizes the equivalent CLI commands for this feature.
BOOTP/DHCP Relay Agent
BootP/DHCP Relay Agent enables BootP/DHCP clients and servers to exchange BootP/D HCP messages
across different subnets. The relay agent receives the requests from the clients, and checks the valid hops
and giaddr fields. If the number of hops is greater than the configured, the agent assumes the packet is
looped through the agents and discards the packet. If giaddr field is zero the agent must fill in this field
with the IP address of the interface on which the request was received. The agent unicasts the valid
packets to the next configured destination. The server responds with a unicast BOOTREPLY addressed
to the relay agent closest to the client as indicated by giaddr field. Upon reception of the BOOTREPLY
from the server, the agent forwards this reply as broadcast or unicast on the interface form where the
BOOTREQUEST was arrived. This interface can be identified by giaddr field.
T he PowerConnect 6200 Series DHCP component also supports DHCP relay agent options to identify
the source circuit when customers are connected to the Internet with high-speed modem. The relay
agent inserts these options when forwarding the request to the server and removes them when sending
the reply to the clients.
If an interface has more than one IP address, the relay agent should use the primary IP address
configured as its relay agent IP address.
Table 9-19. NSF OSPF Graceful Restart Command
CLI Command Description
nsf Enables non-stop forwarding.
nsf helper Enables helpful neighbor functionality for the OSPF protocol.
nsf helper strict-lsa-checking Requires that an OSPF helpful neighbor exit helper mode whenever a
topology change occurs.
show ip ospf Displays information relevant to the OSPF router.
show ip ospf neighbor This command displays information about OSPF neighbors.