Command Line Reference Guide

Open Shortest Path First (OSPFv2 and OSPFv3) | 1037
Usage
Information
When you bring a new router onto an OSPF network, you can configure the router to function as a stub
router by globally reconfiguring the OSPF link cost so that other routers do not use a path that forwards
traffic destined to other networks through the new router for a specified time until the router’s
switching and routing functions are up and running, and the routing tables in network routers have
converged.
By using the max-metric router-lsa command, you force the link cost of all OSPF non-stub links to
the maximum link cost (65535). The advertisement of this maximum metric causes other routers to
assign a cost to the new router that is higher than the cost of using an alternate path. Because of the
high cost assigned to paths that pass through the new router, other routers will not use a path through
the router as a transit path to forward traffic to other networks.
Use the max-metric router-lsa command to gracefully shut down or reload a router without dropping
packets destined for other networks.
Example
Figure 38-2. Command Example: max-metric router-lsa
Note: If you enter the max-metric router-lsa command without an option (on-startup
announce-time or on-startup wait-for-bgp [wait-time]), the maximum metric of 65535 is
always announced in LSAs sent by the router.
FTOS(conf)#router ospf 10
FTOS(conf-router_ospf)#log-adjacency-changes
FTOS(conf-router_ospf)#network 4.1.1.0/24 area 0
FTOS(conf-router_ospf)#network 1.1.1.0/24 area 1
FTOS(conf-router_ospf)#max-metric router-lsa on-startup wait-for-bgp
FTOS(conf-router_ospf)#exit
FTOS(conf)#show ip ospf
Routing Process ospf 10 with ID 100.1.1.1 Virtual router default-vrf
Supports only single TOS (TOS0) routes
It is an Area Border Router
Originating router lsas with maximum metric
Time remaining 00:07:07
Condition : On-Startup while BGP is converging for 600 secs. State : Active
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Convergence Level 0
Min LSA origination 5 secs, Min LSA arrival 1 secs
Number of area in this router is 2, normal 2 stub 0 nssa 0
Area BACKBONE (0)
Number of interface in this area is 1
SPF algorithm executed 3 times
Area ranges are
Area 1
Number of interface in this area is 1
SPF algorithm executed 3 times
Area ranges are
FTOS(conf)#show ip ospf database router
Exception Flag: Announcing maximum link costs
LS age: 198
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 2.1.1.1
Advertising Router: 2.1.1.1
LS Seq Number: 80000005
Checksum: 0x9F5D
Length: 48
Number of Links: 2