OSPF protocol configuration command directory
This chapter introduces mainly relevant commands
of OSPF Which will be Used to configure parameters and monitor the state of OSPF.
Use command “area authentication” to authenticate an OSPF
area under route configuration mode. Use command “no
area area-id authentication” to disable the authentication on an area
and “no
area area-id” to delete an area.
area area-id authentication [simple |
message-digest]
no area area-id authentication
no area area-id
Parameter:
area-id |
Area need to be authenticated |
simple |
(Alternative 1) Use plaintext method
to authenticate. |
message-digest |
(Alternative 1) Use MD5 method to
authenticate. |
Default:
It does not have to authenticate when
receiving OSPF packet on the interface.
Command mode:
route configuration mode
Explanation:
The value of authentication will be written
into OSPF packet. Verification types of all routers in the same area should be
the same. All OSPF routers in a network should keep same authentication
password if they want to communicate with each other.
Example:
The following example show plaintext-authentication on area 0 and 36.0.0.0.
interface ethernet 1/0
ip address 131.119.251.201 255.255.255.0
ip ospf password adcdefgh
!
interface ethernet 1/0
ip address 36.56.0.201 255.255.0.0
ip ospf password ijklmnop
!
router ospf 1
network 36.0.0.0 255.0.0.0 area 36.0.0.0
network 131.119.0.0 255.255.0.0 area 0
area 36.0.0.0 authentication simple
area 0 authentication simple
Relevant command:
ip ospf password
ip ospf message-digest-key
Use “area area-id default-cost cost” to designate the cost of default summary
routes sent to NSSA or STUB area. If you want to resume the default value of
the cost , use command “no area area-id default-cost”
area area-id default-cost
cost
no area area-id default-cost
no area area-id
Parameter:
area-id |
Means ID of stub area |
cost |
Cost |
Default:
Default value is 1.
Command mode:
route configuration mode
Explanation:
This
command can only take effect on the area-border routers connected to NSSA or
STUB area.
After configuring the command “area stub
default-information-originate”, the router will generate LSA
(SUM_NET_LSA) containing default router
information to relevant stub areas. And the cost configured by this command
will be used in this LSA.
Note: If use command “no area area-id”
(without any parameter) to delete the area, all subcommand related to the area
will be disabled , such as: area authentication, area default-cost, area nssa,
area range, area stub, and area virtual-link.
Example:
Set default cost of stub network 36.0.0.0 as 20 as the following
section:
interface ethernet 1/0
ip address 36.56.0.201 255.255.0.0
!
router ospf 201
network 36.0.0.0 255.0.0.0 area 36.0.0.0
area 36.0.0.0 stub
area 36.0.0.0 default-cost 20
Relevant command:
area nssa
area
stub
Summarize routes on area border. Use “no area range” to cancel it.
area area-id range address mask[ not-advertise
]
no area area-id range address mask not-advertise
no
area area-id range address mask
no
area area-id
Parameter:
area-id |
Referring to the area to process
route summary. It could be either a decimal number or an ip address. |
address |
IP address |
mask |
IP mask |
advertise |
To release after being
summarized. |
not-advertise |
Not to release after being summarized. |
Default:
It doesn’t work.
Command mode:
route configuration mode
Explanation:
The command
“area
range” is only used on Area
Border Router.. ABR broadcasts
one summarized route to other routers, therefore the route on the border of an
area is concentrated and there is only one summarizing route for each address
range outside of the area.
This command can be configured on the
router with multiple areas. Hence OSPF can summarize several address ranges.
Note: If use command “no
area area-id” (without any
parameter) to delete the area, all subcommand related to the area will be
disabled , such as: area authentication, area default-cost, area nssa, area
range, area stub, and area virtual-link.
Example:
In the following example, area range for sub-network 36.0.0.0
and 192.42.110.0 are configured.
interface ethernet 0
ip address 192.42.110.201 255.255.255.0
!
interface ethernet 1
ip address 36.56.0.201 255.255.0.0
!
router ospf 201
network 36.0.0.0 255.0.0.0 area 36.0.0.0
network 192.42.110.0 255.0.0.0 area 0
area 36.0.0.0 range 36.0.0.0 255.0.0.0
area 0 range 192.42.110.0 255.255.255.0
To configure an area as a stub area. “No area stub”
command is used to disable the settings.
area area-id stub [no-summary]
no area area-id stub
no area area-id
Parameter:
area-id |
Set the area id of stub area. It can
be either a decimal number or an ip address. |
no-summary |
(Option 1) It is forbidden that ABRrouter sends summarizing link
to stub area. |
Default:
No stub area is defined.
Command mode:
Route configuration mode
Explanation:
It is necessary to configure “area stub” command on all routers
and access severs in the stub area. ABRrouter uses “default-cost”
option (in command “area”) to
set the cost for the inner router to reach the stub area border.
There are two commands related to
stub area : “area xx stub” and “area xx default-cost”. All routers and access
severs connected to stub area should be configured with “area stub”. And sub command “default-cost” is only
used on the area border routers connected to stub area. The default-cost option provides the metric for the summary default
route generated by the ABR into the stub area.
In order to reduce the number of LSA a
little further, “no-summary” could be used
on ABRrouter to
prohibit sending summarizing LSA into stub area.
Note: If use command “no area area-id” (without
any parameter) to delete the area, all subcommand related to the area will be disabled
, such as: area authentication, area default-cost, area nssa, area range, area
stub, and area
virtual-link.
Example:
The following example assigns a default
cost 20 to stub network 36.0.0.0:
interface ethernet 0
ip address 36.56.0.201 255.255.0.0
!
router ospf 201
network 36.0.0.0 255.255.255.0 area
36.0.0.0
area 36.0.0.0 stub
area 36.0.0.0 default-cost 20
Relevant command:
area authentication
area
default-cost
To define an
OSPF virtual link, use the area virtual-link router
configuration command with the optional parameters. To remove a virtual link,
use the no form of this command.
area
area-id virtual-link neighbor-ID
[dead-interval dead-value][ hello-interval hello-value][ retransmit-interval retrans-value][ transdly dly-value][ password pass-string]
[ message-digest-key key-id
MD5 md5-string]
no area area-id
virtual-link neighbor-ID
area-id |
Area ID assigned to the transit area
for the virtual link. This can be either a decimal value or a valid IP
address. There is no default. |
neighbor-id |
Router ID associated with the virtual
link neighbor. The router ID appears in the show ip ospf display. It
is internally derived by each router from the router's interface IP
addresses. This value must be entered in the format of an IP address. There
is no default. |
hello-interval seconds |
(Optional) Time in seconds between the
Hello packets that the router sends on an interface. Unsigned integer value
to be advertised in the router's Hello packets. The value must be the same
for all routers attached to a common network. The default is 10 seconds. |
retransmit-interval seconds |
(Optional) Time in seconds between link
state advertisement retransmissions for adjacencies belonging to the
interface. Expected round-trip delay between any two routers on the attached
network. The value must be greater than the expected round-trip delay. The
default is 5 seconds. |
transdlyseconds |
(Optional) Estimated time in seconds it
takes to transmit a link state update packet on the interface. Integer value
that must be greater than zero. Link state advertisements in the update
packet have their age incremented by this amount before transmission. The
default value is 1 second. |
dead-interval seconds |
(Optional) Time in seconds that a
router's Hello packets are not seen before its neighbors declare the router
down. Unsigned integer value. The default is four times the Hello interval,
or 40 seconds. As with the Hello interval, this value must be the same
for all routers attached to a common network. |
password pass-string |
(Optional) Password to be used by
neighboring routers. Any continuous string of characters that you can enter
from the keyboard up to 8 bytes long. This string acts as a key that will
allow the authentication procedure to generate or verify the authentication
field in the OSPF header. This key is inserted directly into the OSPF header
when originating routing protocol packets. A separate password can be
assigned to each network on a per-interface basis. All neighboring routers on
the same network must have the same password to be able to route OSPF
traffic. |
message-digest-key key-id md5 key |
(Optional) Key identifier and password
to be used by neighboring routers and this router for MD5 authentication. The
keyid is a number in the range 1 through 255. The key is an
alphanumeric string of up to 16 characters. All neighboring routers on the
same network must have the same key identifier and key to be able to route
OSPF traffic. There is no default value. |
area-id: No area ID is predefined.
neighbor-id: No router ID is predefined.
hello-interval seconds: 10 seconds
retransmit-interval seconds: 10 seconds
transdly seconds: 1 second
dead-interval seconds: 40 seconds
password key: No key is predefined.
message-digest-key keyid md5 key: No key is
predefined.
Ospf Router
configuration
In OSPF, all
areas must be connected to a backbone area. If the connection to the backbone
is lost, it can be repaired by establishing a virtual link.
The smaller the
Hello interval, the faster topological changes will be detected, but more
routing traffic will ensue.
The setting of
the retransmit interval should be conservative, or needless retransmissions
will result. The value should be larger for serial lines and virtual links.
The transmit
delay value should take into account the transmission and propagation delays
for the interface.
A router will
use the specified authentication key only when authentication is enabled for
the backbone with the area area-id authentication router
configuration command.
The two
authentication schemes, simple text and MD5 authentication, are mutually
exclusive. You can specify one or the other or neither. Any keywords and
arguments you specify after authentication-key key or message-digest-key
keyid md5 key are ignored. Therefore, specify any optional
arguments before such a keyword-argument combination.
The following
example establishes a virtual link with default values for all optional
parameters:
The following
example establishes a virtual link with MD5 authentication:
area authentication
show ip ospf virtual-link
Monitor the procedure establishing OSPF adjacency:
debug ip ospf adj
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
The produce establishing OSPF adjacency could be consulted
according to output information of the command.
Example:
Router# debug ip ospf adj
OSPF: Interface
192.168.40.0 on Serial1/0 going down
OSPF
NBR: 192.168.40.2 address 192.168.40.2 on Serial1/0 is dead, state DOWN
OSPF
NBR: 192.168.40.3 address 192.168.40.3 on Serial1/0 is dead, state DOWN
Line on
Interface Serial1/0, changed state to up
Line
protocol on Interface Serial1/0 changed state to up
OSPF:
Interface 192.168.40.0 on Serial1/0 going Up
OSPF: 2
Way Communication to 192.168.40.2 on Serial1/0, state 2WAY
OSPF:
NBR 192.168.40.2 on Serial1/0 Adjacency OK, state NEXSTART.
OSPF:
NBR Negotiation Done. We are the SLAVE
OSPF:
NBR 192.168.40.2 on Serial1/0 Negotiation Done. We area the SLAVE
OSPF:
Exchange Done with 192.168.40.2 on Serial1/0
OSPF:
Loading Done with 192.168.40.2 on Serial1/0, database Synchronized (FULL)
OSPF: 2
Way Communication to 192.168.40.3 on Serial1/0, state 2WAY
OSPF:
NBR 192.168.40.3 on Serial1/0 Adjacency OK, state NEXSTART.
OSPF:
NBR Negotiation Done. We are the SLAVE
OSPF:
NBR 192.168.40.3 on Serial1/0 Negotiation Done. We area the SLAVE
OSPF:
Bad Sequence with 192.168.40.3 on Serial1/0, state NEXSTART
OSPF:
NBR Negotiation Done. We are the SLAVE
OSPF:
NBR 192.168.40.3 on Serial1/0 Negotiation Done. We area the SLAVE
OSPF:
Exchange Done with 192.168.40.3 on Serial1/0
OSPF:
Loading Done with 192.168.40.3 on Serial1/0, database Synchronized (FULL)
……
Monitor events of interface and neighbor:
debug ip ospf events
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
Events triggered by OSPF interface actions and neighbor operations
can be consulted according to the
output information of the command.
Example:
Router# debug ip ospf events
OSPF:
Interface Serial1/0 going Up
OSPF:
INTF(192.168.40.0) event INTF_UP
OSPF: NBR(192.168.40.2)
event HELLO_RX
OSPF:
NBR(192.168.40.2) event TWOWAY
OSPF:
NBR(192.168.40.2) event ADJ_OK
OSPF:
NBR(192.168.40.2) event NEGO_DONE
OSPF:
NBR(192.168.40.2) event EXCH_DONE
OSPF:
NBR(192.168.40.2) event LOAD_DONE
OSPF:
NBR(192.168.40.3) event HELLO_RX
OSPF:
NBR(192.168.40.3) event TWOWAY
OSPF:
NBR(192.168.40.3) event ADJ_OK
OSPF:
NBR(192.168.40.3) event NEGO_DONE
OSPF:
NBR(192.168.40.3) event SEQ_MISMATCH
OSPF:
NBR(192.168.40.3) event NEGO_DONE
OSPF:
NBR(192.168.40.3) event EXCH_DONE
OSPF:
NBR(192.168.40.3) event LOAD_DONE
……
Monitor the flooding process of OSPF link state database:
debug ip ospf flood
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
The flooding process of OSPF link state
database could be viewed according to the command output information.
Example:
Router# debug ip ospf flood
OSPF:
recv UPDATE, type 1 LSID 192.168.40.2 ADV_RTR 192.168.40.2 AGE 2 SEQ 0x8000022B
OSPF:
Send UPDATE, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 1 SEQ
0x80000234
OSPF:
Send ACK, type 1 LSID 192.168.40.2 ADV_RTR 192.168.40.2 AGE 2 SEQ 0x8000022B
OSPF:
recv ACK, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 1 SEQ
0x80000234
OSPF:
recv ACK, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 18 SEQ
0x80000233
OSPF:
Send UPDATE, type 1 LSID 192.168.40.2 ADV_RTR 192.168.40.2 AGE 10 SEQ
0x8000022B
OSPF:
recv UPDATE, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 5 SEQ 0x8000021C
OSPF:
Send UPDATE, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 6 SEQ 0x8000021C
OSPF:
Send UPDATE, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 1 SEQ
0x80000235
OSPF:
recv ACK, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 4 SEQ 0x8000021C
……
Supervise
the generating process of LSA of
OSPF:
debug ip ospf lsa-generation
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
The
produce of LSA generation can be viewed according to the command output
information.
Example:
router# debug ip ospf lsa-generation
……
OSPF:
Send UPDATE, type 1 LSID 192.168.40.2 ADV_RTR 192.168.40.2 AGE 10 SEQ
0x8000022D
OSPF:
recv UPDATE, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 5 SEQ 0x8000021E
OSPF:
Send UPDATE, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 6 SEQ 0x8000021E
OSPF:
Send UPDATE, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 1 SEQ
0x80000239
OSPF:
recv ACK, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 4 SEQ 0x8000021E
OSPF:
Send ACK, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 5 SEQ 0x8000021E
OSPF:
recv UPDATE, type 1 LSID 192.168.40.2 ADV_RTR 192.168.40.2 AGE 1 SEQ 0x8000022E
OSPF:
Send UPDATE, type 1 LSID 192.168.40.2 ADV_RTR 192.168.40.2 AGE 2 SEQ 0x8000022E
OSPF:
recv ACK, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 1 SEQ
0x80000239
OSPF:
recv ACK, type 1 LSID 192.168.40.3 ADV_RTR 192.168.40.3 AGE 6 SEQ 0x8000021E
OSPF:
recv ACK, type 1 LSID 192.168.20.240 ADV_RTR 192.168.20.240 AGE 1 SEQ
0x80000239
……
Supervise the packet of ospf:
debug ip ospf packet
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
Senging/Receiving
all kind of OSPF packet can be viewed according to the command output
information.
Example:
router# debug ip ospf packet
OSPF: Recv
HELLO packet from 192.168.40.3 (addr: 192.168.40.3) area 0 from Serial1/0
OSPF:
End of hello processing
OSPF:
Send HELLO to 224.0.0.5 on Loopback0
HelloInt 10 Dead 40 Opt 0x2 Pri 1 len 44
OSPF:
Send HELLO to 224.0.0.5 on Loopback0
HelloInt 10 Dead 40 Opt 0x2 Pri 1 len 44
OSPF:
Send HELLO to 224.0.0.5 on Loopback0
HelloInt 10 Dead 40 Opt 0x2 Pri 1 len 44
OSPF:
Recv HELLO packet from 192.168.40.2 (addr: 192.168.40.2) area 0 from Serial1/0
OSPF:
End of hello processing
OSPF:
Send HELLO to 224.0.0.5 on Serial1/0
HelloInt 30 Dead 120 Opt 0x2 Pri 1 len 52
OSPF:
Recv HELLO packet from 192.168.40.3 (addr: 192.168.40.3) area 0 from Serial1/0
OSPF:
End of hello processing
OSPF:
Send HELLO to 224.0.0.5 on Loopback0
HelloInt 10 Dead 40 Opt 0x2 Pri 1 len 44
……
Supervise the packet- retransmission process of ospf:
debug ip ospf retransmission
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
Retransmiting OSPF packets can be viewed according to command
output information.
Example:
router# debug ip ospf retransmission
OSPF:
retransmit UPDATE to 192.168.40.3 (RID 192.168.40.3), state FULL
……
Supervise the SPF calculation of
OSPF:
debug ip ospf spf
debug ip ospf spf intra
debug ip ospf spf inter
debug ip ospf spf external
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
The SPF calculation process can be viewed according to command
output information.
Example:
router# debug ip ospf spf
OSPF:
run ospf_spf_run
OSPF:
start doing SPF for AREA 0.0.0.0
OSPF:
RTAB_REV(ospf) 1390.
OSPF :
Initializing to do SPF
OSPF:
addroute LSID 192.168.20.240
OSPF:
ospf_nh_find: 192.168.40.2
……
OSPF:
addroute LSID 192.168.40.3
OSPF:
build a OSPF_ROUTE, dest: 192.168.40.3
OSPF:
addroute LSID 192.168.40.2
……
OSPF:
SPF Area A running Network Summary
OSPF:
Processing LS_SUM_NET 192.168.40.24, mask 255.255.255.248, adv 192.168.40.3,
age 599
OSPF:
addroute LSID 192.168.40.24
OSPF:
ospf_build_route RT 192.168.40.24
OSPF:
build route 192.168.40.24(255.255.255.248).
……
OSPF:
Processing LS_SUM_NET 1.1.1.1, mask 255.255.255.255, adv 192.168.20.240, age
228
OSPF:
addroute LSID 192.168.20.236
OSPF:
build a OSPF_ROUTE, dest: 192.168.20.236
OSPF:
start Building AS External Routes
OSPF:
processing LS_ASE 192.168.42.0, mask 255.255.255.248, adv 192.168.20.236, age
258
OSPF:
addroute LSID 192.168.42.0
OSPF:
ospf_build_route RT 192.168.42.0
OSPF:
build route 192.168.42.0(255.255.255.248).
OSPF:
processing LS_ASE 192.168.43.0, mask 255.255.255.0, adv 192.168.20.236, age 258
OSPF:
addroute LSID 192.168.43.0
OSPF:
ospf_build_route RT 192.168.43.0
OSPF:
build route 192.168.43.0(255.255.255.0).
OSPF: processing
LS_ASE 192.168.44.0, mask 255.255.255.0, adv 192.168.20.236, age 258
OSPF:
addroute LSID 192.168.44.0
OSPF:
ospf_build_route RT 192.168.44.0
OSPF:
build route 192.168.44.0(255.255.255.0).
……
OSPF:
end doing SPF for AREA 0.0.0.0
Display field decryption
Field |
Description |
LSA(192.168.20.236,
LS_SUM_ASB) |
ID and
type of LSA |
Supervise
the establishment of SPF tree of OSPF:
debug ip ospf tree
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
The establishment of SPF tree of OSPF can be viewed according to
command output information.
Example:
router# debug ip ospf tree
B3710_221#
OSPF:
add LSA(192.168.40.0, LS_STUB) 1600 under LSA(192.168.20.240, LS_RTR)
OSPF: add LSA(192.168.40.2, LS_RTR) 1600 under
LSA(192.168.20.240, LS_RTR)
OSPF: add LSA(192.168.40.3, LS_RTR) 1600 under
LSA(192.168.20.240, LS_RTR)
OSPF: add LSA(192.168.40.1, LS_STUB) 0 under
LSA(192.168.20.240, LS_RTR)
OSPF: add LSA(192.168.40.3, LS_STUB) 1600 under
LSA(192.168.40.3, LS_RTR)
OSPF: add LSA(192.169.1.5, LS_RTR) 3200 under
LSA(192.168.40.2, LS_RTR)
OSPF: add LSA(192.168.40.18, LS_STUB) 1600 under
LSA(192.168.40.2, LS_RTR)
OSPF: add LSA(192.168.40.2, LS_STUB) 1600 under
LSA(192.168.40.2, LS_RTR)
OSPF: add LSA(192.168.40.17, LS_STUB) 3200 under
LSA(192.169.1.5, LS_RTR)
OSPF: add LSA(192.168.40.24, LS_SUM_NET) 1601
under LSA(192.168.40.3, LS_RTR)
OSPF: add LSA(192.168.40.32, LS_SUM_NET) 3200
under LSA(192.168.40.2, LS_RTR)
OSPF: add LSA(192.168.40.40, LS_SUM_NET) 14577
under LSA(192.169.1.5, LS_RTR)
OSPF: add LSA(192.168.20.236, LS_SUM_ASB) 3200
under LSA(192.168.40.2, LS_RTR)
show field description
Field |
Description
|
LSA(192.168.20.236,
LS_SUM_ASB) |
ID and
type of LSA |
add |
sub-LSA |
under |
parent
LSA |
default-information
originate (OSPF)
Generate a default route into OSPF routing domain
default-information
originate [always] [route-map map-name]
no default-information originate [always] [route-map map-name]
Parameter:
originate |
Use this command, if there has been a
default route and it is expected to be transmitted to other routers. This
parameter will cause the system to transmit an external route into OSPF
routing domain. |
Always |
(Option) Whether the system has a default
route or not, the system will broadcast the default route. |
route-map map-name |
(Option) If route-map is met, a
default route will be generated. |
Default:
default route is not generated
Command mode:
route configuration state
Explanation:
Use either command “redistribute” or command “default-information” to distribute a route
to OSPF routing domain. The router will become ASBR. But ASBR doesn’t generate
a default route into OSPF routing domain in default case, unless “always”
option has been set, otherwise a default route should be configured.
When this command is used, the default
network should be contained in the routing table and must satify condition of
the option “route-map”. If you don’t
want the dependency on the default network in routing table, use command “default-information
originate always route-map”.
Example:
The following example shows the default
route distributed into OSPF routing domain:
router ospf 109
redistribute rip
default-information originate
Relevant command:
Redistribute
Set the default metric value for the
route introduced . Use “no
default-metric” to reset the default value.
default-metric value
no default-metric
Parameter:
The route Metric to be set is “value” with a range from 1 to 4294967295.
Default:
The default route Metric is 10.
Command mode:
route configuration state
Explanation:
The command “default-metric” is used to set the default Metric that is used to introduce the
route of other routing protocol into ospf routing domain. When using the
command “redistribute” to introduce
the route of other routing protocol, the default Metric designated by “default-metric” is
used if no specific route value is designated.
Example:
Set the default metric value to 3 to
distribute routes of other routing protocol.
router_config_ospf_100#default-metric 3
Relevant command:
redistribute
Define the administrative administrative
distance according to the type. Use “no distance ospf” to disable the settings.
distance ospf {[intra-area dist1] [inter-area dist2] [external dist3]}
no distance ospf [intra-area] [inter-area] [external]
Parameter:
intra-area dist1 |
(Option) Set the distance for all
routes of an area. The default value is 110. |
inter-area dist2 |
(Option)Set the distance for all
routes from an area to another area. The default value is 110. |
external dist3 |
(Option)Set the distance for routes from other routing domains, learned by redistribution..
The default value is 110. |
Default:
intra-area: 110
inter-area: 110
external: 150
Command mode:
route configuration state
Explanation:
Should have at least one parameter.
This command has the same function as “distance”. However command “distance
ospf” can
configure the distance of the whole route group not only the route passing
through a certain access list.
Example:
The following example set external distance as 200.
Router A
router ospf 1
redistribute ospf 2
distance ospf external 200
!
router ospf 2
redistribute ospf 1
distance ospf external 200
Router B
router ospf 1
redistribute ospf 2
distance ospf external 200
!
router ospf 2
redistribute ospf 1
distance ospf external 200
Relevant command:
distance
Use route configuration state command “filter” to set route filtering list. Use command “no filter” to reset the default settings.
filter {interface-type interface-number |
*} {in } {access-list access-list-name | gateway access-list-name
| prefix-list prefix-list-name}
filter {interface-type interface-number |
*} {in } {access-list access-list-name | gateway access-list-name
| prefix-list prefix-list-name}
Parameter:
interface-type |
Interface type |
interface-number |
interface number |
* |
All interfaces |
access-list-name |
Name of the access list |
access-list-name |
name of the access list |
prefix-list-name |
Name of the prefix list |
Default:
none
Command mode:
route configuration state
Explanation:
none
Example:
filter * in access-list mylist
Designate the cost needed for the
interface to run “OSPFprotocol”.
Command “no ip ospf cost” is used to
reset the default value.
ip ospf cost cost
no ip ospf cost
Parameter:
“cost” is
the value to be spent for “OSPFprotocol”, ranging
from 1to 65535 (whole number).
Default:
The default value of the cost is calculated according to the
rate of the interface.
Command mode:
interface configuration state
Example:
Set the value of the cost to 2 on the
interface serial 0 for OSPF.
ip ospf cost 2
Designate the cost needed for interface
to run “OSPFprotocol”.
Command “no ip ospf cost” is used to
reset the default value.
Designate the time length to recognize the death of neighboring
routers. Command “no ip ospf dead-interval” is used to reset default value.
ip ospf dead-interval seconds
no ip ospf dead-interval
Parameter:
“Seconds” is
the time value of the death of neighboring routers, which is calculated in
seconds. The legal range is 1 ~ 65535
Default:
The default time length of the death of
neighboring routers on the interface is 40 seconds.
Command mode:
interface configuration state
Explanation:
Value of dead-interval will be written
into “Hello” packet and
will be sent together with “hello” packet. It should be ensured that the dead-interval is in accordance
with the dead-interval set in the “hello” packet by other adjacent neighbors on the interface and is 4 times
the value of Hello-interval.
Example:
Configure dead-interval of neighboring routers
on interface Serial0 as 60 seconds.
router_config_S1/0#ip ospf dead-interval 60
Relevant command:
ip ospf hello-interval
Designate the interval to send Hello
packet on the interface. Command “no ip ospf
hello-interval” reset the default value.
ip ospf hello-interval seconds
no ip ospf hello-interval
Parameter:
“Seconds” is the interval to send HELLO packet and is
calculated in seconds. The range is from 1 to 255.
Default:
The default interval to send HELLO packet on the interface is
10 seconds.
Command mode:
interface configuration mode
Explanation:
The value of the hello-interval will be
written into the HELLO packet and will be sent together with the HELLO packet.
The smaller the value of hello-interval is, the more quickly the topology of
the network will be found and the more the router cost will cost. It should be
ensured that the value of hello-interval is in accordance with the
hello-interval set by other adjacent neighbors on the interface.
Example:
Configure the interval to send HELLO
packet on interface Serial1/0 as 20 seconds.
router_config_S1/0#ip ospf hello-interval 20
Relevant command:
ip ospf dead-interval
Set that ospf applies MD5 authentication. Use “no
ip ospf message-digest-key” to disable the setting.。
ip ospf message-digest-key keyid md5 key
no
ip ospf message-digest-key keyid
Parameter:
keyid |
Authenticate ID(1 –
255). |
key |
16-digit letter and number
string |
Default:
OSPF MD5 authentication is not used.
Command mode:
interface configuration mode
Explanation:
Usually each interface uses a key value to generate
authentication information or validate the package received. Both adjacent
routers should have the same key.
The process to change the key is as follows.
If the current configuration is as the following:
interface ethernet 1
ip ospf message-digest-key 100 md5 OLD
Change it into the following configuration:
interface ethernet 1
ip ospf message-digest-key 101 md5 NEW
The system assumes its neighboring
router has no new key either. It will send the same package in many copies.
Each copy applies different key value. This example router will send each
package in 2 copies with one copy’s key=100 and
the other one key=101.
This allows the neighboring routers to continue to communicate
when the manager is revising a key value. The process stops as soon as it is
found that all adjacencies apply a new key value. When the system receives
packages with a new key value sent by neighboring router, it will recognize
that neighboring router has a new key.
After all neighbors have applied a new key, the old key will be
deleted. In this example, it should be configured as the following:
interface ethernet 1/0
no ip ospf message-digest-key 100
Thus the Ethernet interface 1/0 can only apply key=101 to make the
authentication.
Suggest that each interface had better
not to have several keys. Former key value should be deleted after new key value
is added to prevent that local system uses former key to communicate with
unfriendly system knowing the former system. Deleting the former key value will
also reduce the communication burden.
Example:
The following example sets a new
key=19. The password is 8ry4222:
interface ethernet 1
ip ospf message-digest-key 10 md5 xvv560qle
ip ospf message-digest-key 19 md5 8ry4222
Relevant command:
area authentication
Set network type of the interface. command “no ip ospf
network” is used to disable the setting.
ip ospf network { broadcast | nonbroadcast |
point_to_multipoint | point-to-point}
no ip ospf network { broadcast | nonbroadcast |
point_to_multipoint | point-to-point}
Parameter:
broadcast |
Set
the network type of interface as broadcast type. |
nonbroadcast |
Set the network type of interface as non-broadcast NBMA type. |
point-to-point |
Set
the network type of interface as the point-to-point type. |
point-to-multipoint |
Set
the network type of interface as point-to-multipoint type. |
Command mode:
interface configuration mode
Explanation:
On the broadcast network without
multi-address access ability, the interface should be configured as NBMA type.
If it cannot be ensured that any two routers on a NBMA network are accessible
to each other, the network should be set as point-to-multipoint type.
Example:
Configure the interface Serial1/0 as
non-broadcast NBMA type.
router_config_S1/0#ip ospf network nonbroadcast
Use command “ip ospf passive” to disable sending HELLO packet
on the interface. Use “no ip ospf passive” to enable sending HELLO packet.
ip ospf passive
no ip ospf passive
Parameter:
none
Default:
Send HELLO massage on interface.
Command mode:
interface configuration mode
Explanation:
If you disable sending HELLO massage on a certain interface, a
specific sub network will continue to announce to other interfaces and route
update from other router to this interface will continue to be accepted and
processed. This is usually used on STUB network. There usually aren’t any other
OSPFrouter
on such a network.
Example:
The
following example sends HELLO packet for network 131.108.0.0 to all interfaces (excluding Ethernet interface
1/0):
interface ethernet 1/0
ip address 172.16.0.1 255.255.0.0
ip ospf passive
router ospf 110
network 172.16.0.0 255.255.0.0 area 1
Configure password for plain-text authentication on the interface
. Use “no ip ospf password” to disable the setting.
ip ospf password password
no
ip ospf password
Parameter:
password |
Any sequential 8-digit character
string. |
Default:
No Password
Command mode:
interface configuration mode
Explanation:
The
password generated from this command inserts route information package
directly. You can configure one password for each netework on each interface.
All neighbors on the interface should have the same password to exchange route
information.
Note: This command will validate only after the command “area
authentication” configured.
Example:
ip ospf password yourpass
Relevant command:
area authentication
Configure the priority for electing “DR
router” on the interface. Use “no ip ospf
priority” to reset the default value.
ip ospf priority priority
no ip ospf priority
Parameter:
“priority”
refers to the priority with rightful range from 0 to 255.
Default:
The default priority of the interface
for electing DR router is 1.
Command mode:
interface configuration mode
Explanation:
When both routers connected to the same section of a network
want to become DR, choose the one with a higher priority. If they share the
same priority, choose the one with the bigger router ID number. A router with priority 0 will not be elected as “DR”
or “BDR”. The priority will validate only when it is configured on
non-point-to-point network.
Example:
Set
the priority of interface Serial1/0
for electing DR as 8.
router_config_S1/0#ip ospf priority 8
Relevant command:
neighbor
Designate the retransmission interval for transmitting link state
packet to the adjacent neighbor on the interface. Command “no
ip ospf retransmit” reset the default value.
ip ospf retransmit seconds
no ip ospf retransmit
Parameter:
“seconds” is the retransmit interval for
transmitting link state broadcast between interface and neighboring router and
is calculated in seconds. Its range is from 1 to 65535.
Default:
The
default retransmission interval for transmitting link state broadcast between
interface and neighboring router is 5 seconds.
Command mode:
interface configuration mode
Explanation:
When a router send link state broadcast to its neighboring router,
it will keep the link state packet until receiving confirmation from its
neighbor. If confirmation is not received within the interval “seconds”, it should be
retransmitted. Value of “seconds” should be longer than the round-trip time
between the routers.
Example:
Configurate
the retransmit interval for transmitting link state broadcast between interface
Serial1/0 and
neighboring router as 8 seconds.
router_config_S1/0#ip ospf retransmit 8
Configure the time delay value for transmitting link state
broadcast on the interface. Use “no ip ospf transit-delay” to reset the default
value.
ip ospf transit-delay time
no ip ospf transit-delay
Parameter:
Configurate
the retransmit interval for transmitting link state broadcast between interface
Serial1/0 and neighboring
router as 8 seconds.
Default:
The default time delay value for transmitting link state
broadcast on the interface is 1 second.
Command mode:
interface configuration mode
Example:
Configure the time delay value for transmitting link state
broadcast on interface Serial1/0 as 3 seconds.
router_config_S1/0#ip ospf transit-delay 3
Configure the OSPFrouter in adjacency with non-broadcast
network. Use “no neighbor” to delete it.
neighbor ip-address [priority
number] [poll-interval seconds] [cost number]
no neighbor ip-address [priority number] [poll-interval
seconds] [cost number]
Parameter:
ip-address |
IP address of neighboring router. |
priority number
|
(Option 1) 8-digit
priority. Default value is 0. This option cannot be used for point-multipoint
interface. |
poll-interval seconds |
(Option 1)
Referring to poll interval. Suggest that it should be longer than hello
interval for RFC 1247. This option cannot be used for point-multipoint
interface. |
cost number
|
(Option 1)
Designate cost (1-65535) for neighboring router. If the cost is not
designated, use the cost designated by “ip ip ospf co”. This option is the only one that works for a point-multipoint
network. It is not fitted for NBMA network. |
Default:
none
Command mode:
router configuration mode
Explanation:
For X.25 and frame relay network, you can set OSPF to work with
broadcast type. Referring to the following for the details:
Command “X25
map” and “frame-relay
map”
For each non-broadcast neighbor, the configuration should be
configured within the router. The neighbor address should be the main address
of the interface.
If
the neighboring router is in a non-active state, it is still necessary to send
hello packages to it. These hello packages will be sent at poll interval.
When
turning on the router, a hello package is only sent to the router with a
non-zero priority. This router can be changed into DR and BDR routers. When DR and BDR routers are selected, DR and BDR routers will send hello package all neighbor to
form adjacencies
Example:
The
following example designate router 131.108.3.4
address as non-broadcast network with priority 1 and poll interval 180 seconds.
router ospf
neighbor 131.108.3.4 priority 1 poll-interval 180
The following example refers to the configuration of
point-to-multipoint non-broadcast network.
interface Serial0
ip address 10.0.1.1 255.255.255.0
ip ospf network point-to-multipoint non-broadcast
encapsulation frame-relay
no keepalive
frame-relay local-dlci 200
frame-relay map ip 10.0.1.3 202
frame-relay map ip 10.0.1.4 203
frame-relay map ip 10.0.1.5 204
no shut
!
router ospf 1
network 10.0.1.0 255.255.255.0 area 0
neighbor 10.0.1.3 cost 5
neighbor 10.0.1.4 cost 10
neighbor 10.0.1.5 cost 15
Relevant command:
ip ospf priority
Start OSPF on the interface if it is covered by the network, and
specify the area ID. Command “no network” is used to disable network.
network network mask area area_id [ advertise |
not-advertise ]
[ no ] network network mask area area_id [ advertise |
not-advertise ]
Parameter:
“Network” and “mask” are network
IP address and mask with dotted decimal notation.
“area_id” is
the area number.
Default:
The default of the system doesn’t configure the network range.
Command mode:
route configuration mode
Explanation:
Once a network range is added in the area,
all internal routes of IP addresses reaching the network range within the area
will not be broadcast to other areas individually. Only abstract information of
routes within the whole network range. Introducing network range and
restriction to the network range will reduce the communication between routes
of different areas.
Example:
Define network range 10.0.0.0 255.0.0.0
and add it into area 2.
router_config_ospf_10#network 10.0.0.0 255.0.0.0 area 2
Use route configuration state command “redistribute” to set ospf to redistribute route of other routing protocol. Use command “no redistribute” to reset default setting.
redistribute protocol [as-number] [route-map map-tag]
no redistribute protocol [as-number] [route-map map-tag]
Parameter:
Protocol |
The
source
protocol to be distributed can only be one of the following: beigrp, bgp,
connect, ospf, rip and static . |
as_number |
(Optional)
Autonomous system number. There is no such a parameter for connect, rip and static. |
map-tag |
(Optional)
Name of route-map |
don’t
redistribute
Command mode:
route configuration mode
Explanation:
none
Example:
Redistribute
ospf 0 (redistribute ospf routes in process 0)
Enable OSPF routing protocol on the router. Use “No router
ospf” to prohibit routers from using ospf.
router ospf process-id
no
router ospf process-id
Parameter:
process-id |
The parameter used to mark OSPF router process internally. It
is a non-negative integer allocated locally. It uniquely refers to a route
processing process. |
Default:
No ospf route processing is defined.
Command mode:
global configuration mode
Explanation:
There can be several ospf route-processing processes in a router.
Example:
An ospf route process with ID 109 is
configured as the following.
router ospf 109
Relevant command:
network area
Show main information of OSPF.
show ip ospf [process-id]
Parameter:
process-id (alternative)process
number
Default:
none。
Command mode:
supervisor mode
Explanation:
The command output information can be used to help users to
diagnose OSPF failure. With process-id, only global configuration
information of corresponding OSPF process will be shown.
Example:
Show all
configuration information of OSPF process:
router#show ip ospf
OSPF process: 1, Router ID is 192.168.99.81
Distance: intra-area 110 inter-area 130 external
150
Source Distance Access-list
240.240.1.1/24 1 what
SPF schedule delay 5 secs, Hold time between two
SPFs 10 secs
Number of areas is 3
AREA: 1
Number of interface in this area is 1(UP: 1)
Area authentication type: None
AREA: 36.0.0.1
This is a stub area.
Number of interface in this area is 0(UP: 0)
Area authentication type: None
AREA: 192.168.20.0
Number of interface in this area is 0(UP: 0)
Area authentication type: None
10.0.0.0/255.0.0.0 Not-Advertise
140.140.0.0/255.255.0.0 Advertise
filter list on receiving UPDATE is Gateway: weewe
filter list on sending UPDATE is Prefix: trtwd
Summary-address list:
150.150.0.0/16 advertise
router#
Show field description.
Area |
Description |
OSPF process: 1 |
ID of OSPF process |
Router ID is 192.168.99.81 |
ID of router |
Distance: intra-area 110 inter-area 130 external 150 |
Default
administrative distance adopted when the routing is generated by current
router |
Source Distance Access-list |
Administrative
distance based on access list configured |
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs |
Two 0SPF related TIMER values |
Number of areas is 3 |
The number
of area configured currently and parameter configured in each area |
filter list on receiving… |
Filter
configured for imported route |
filter list on sending |
Filter
configured for exported route |
Summary-address list |
route
summarizing configured |
Show data item of ABR and ASBR in router.
show ip ospf border-routers
Parameter:
none
Default:
none
Command mode:
supervisor mode
Example:
router#
router#sh ip os bor
OSPF process: 1
Codes: i - Intra-area route, I - Inter-area route
Destination Adv-Rtr Cost Type Area
i 192.168.20.77 192.168.20.77 11 ABR 0
router#
Field |
Description |
Destination |
ID of target router |
Adv-Rtr |
Next hop to reach target router |
Cost |
Cost of using this route. |
Type |
Type of target router. It can be ABR, ASBR or both of them. |
Area |
Area ID
from which the router is learned. |
show ip ospf database
show OSPF link state database
information
show ip ospf database
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
OSPF link state database information can be viewed according to
this command. It will help the users to diagnose the failure.
Example:
router#
router#show ip ospf database
OSPF process: 1
(Router ID 192.168.99.81)
AREA: 0
Router Link States
Link ID ADV Router Age Seq # Checksum Link count
192.168.20.77 192.168.20.77 77 0x8000008a 0x90ed 1
192.168.99.81 192.168.99.81 66 0x80000003 0xd978 1
Net Link States
Link ID ADV Router Age Seq # Checksum
192.168.20.77 192.168.20.77 80 0x80000001 0x9625
Summary Net Link States
Link ID ADV Router Age Seq # Checksum
192.168.99.0 192.168.99.81 87 0x80000003 0xd78c
AREA: 1
Router Link States
Link ID ADV Router Age Seq # Checksum Link count
192.168.99.81 192.168.99.81 70 0x80000002 0x0817 1
Summary Net Link States
Link ID ADV Router Age Seq # Checksum
192.168.20.0 192.168.99.81 66 0x80000006 0xd1c1
Field |
Description
|
AREA: 1 |
the area
where it is in |
Router Link States/Net Link States/Summary Net Link States |
LSA type |
Link ID |
LSA ID. |
ADV Router |
Advertising
router |
Age |
LSA age |
Seq # |
Sequence
number |
Checksum |
checksum
value |
show ip ospf interface
Show OSPF interface information.
show ip ospf interface
Parameter:
none
Default:
none
Command mode:
supervisor mode
Explanation:
View configuration and running state of
OSPF on the interface.
Example:
router#sh ip os int
Ethernet 1/0 is up, line protocol is up
Internet Address: 192.168.20.81/24, Nettype:
BROADCAST
OSPF process is 1, AREA 0, Router ID 202.96.135.201
Cost 10, Transmit Delay is 1 sec, Priority 1
Hello interval 10, Dead timer 40, Retransmit 5
Designated Router id 131.119.254.10, Interface
address 131.119.254.10
Backup Designated router id 131.119.254.28,
Interface addr 131.119.254.28
Neighbor Count is 8, Adjacent neighbor count is 2
Adjacent with neighbor 131.119.254.28 (Backup
Designated Router)
Adjacent with neighbor 131.119.254.10 (Designated
Router)
router#
Field |
Description |
Internet Address: |
IP address
of the interface |
Nettype |
OSPF
interface network type |
OSPF process is |
The process
number of the OSPF |
AREA |
the area
where it is |
Router ID |
router ID of
the process where it is |
Cost |
interface
cost |
Transmit Delay is |
transmit
delay |
Priority |
priority of
the router interface |
Hello interval |
hello
interval |
Dead timer |
dead time |
Retransmit |
retransmit
interval |
OSPF INTF State is |
OSPF
interface state |
Designated Router id |
Router ID
of DR and IP address of the interface on DR |
Backup Designated router id |
Router ID
of BDR and IP address of the interface on BDR |
Neighbor Count is |
number of
neighboring routers |
Adjacent neighbor count is |
number of
the neighbors that have established adjacency |
Adjacent with neighbor |
list of the
neighbors that have established adjacency |
show ip ospf neighbor
Show OSPF adjacency point information
show ip ospf neighbor
Parameter:
none
Default:
none。
Command mode:
supervisor mode
Explanation:
The information of OSPF neighbors can
be viewed according to command output. It will help the user to make sure if OSPF
neighbor configuration is right and diagnose OSPF failure.
Example:
router#show ip ospf neighbor
OSPF process: 1
AREA 1
21.0.0.32 1 FULL /DR 31 192.168.99.32 Ethernet1/0
AREA 36.0.0.1
199.199.199.137 1 EXSTART/DR 31 202.19.19.137
Ethernet2/1
AREA 192.168.20.0
140.140.0.46 1 FULL /DR 108 140.140.0.46 Serial 1/0
133.133.2.11 1 FULL /DR 110 133.133.2.11 Serial1/0
192.31.48.200 1 FULL / DROTHER 31 192.31.48.200
Ethernet1/0
show field description
Field |
description |
OSPF process |
number of
the process of OSPF where it is |
AREA |
the area
where it is |
Neighbor |
ID of the
neighbor |
Pri |
priority of
the neighbor |
State |
the state
of the connection with the neighbor |
DeadTime |
time of
invalidation of the neighbor |
Address |
IP address
of the neighbor |
Interface |
interface
used by router to reach the neighbor |
To display
parameters about and the current state of OSPF virtual links, use the show
ip ospf virtual-link command.
show ip ospf virtual-link
This command
has no arguments or keywords.
Command Mode
supervisor mode
The information
displayed by show ip ospf virtual-link is useful in debugging
OSPF routing operations.
The following
is sample output from the show ip ospf virtual-link command:
RouterA#show ip ospf vir
Virtual Link Neighbor ID
200.200.200.200 (UP)
TransArea: 1, Cost is 1600
Hello interval is 10, Dead timer is 40 Retransmit is 5
INTF Adjacency state is IPOINT_TO_POINT
Show field Description
Field |
Description |
Virtual Link Neighbor ID 200.200.200.200 (UP) |
Specifies the OSPF neighbor, and if the
link to that neighbor is Up or Down. |
TransArea: 1 |
The transit area through which the
virtual link is formed. |
Cost is 1600 |
The cost of reaching the OSPF neighbor
through the virtual link. |
Hello interval is 10 |
The hello interval on this
virtual-link. |
Dead timer is 40 |
The dead interval on this virtual-link. |
Retransmit is 5 |
The retransmit interval on this virtual
link. |
INTF Adjacency state is IPOINT_TO_POINT |
The state of this virtual link
interface. |
Use route configuration state command “summary-address” to
establish route summary address for OSPF. Use route configuration state command
“no summary-address” to delete route summary address.
summary-address address mask
[not-advertise]
no summary-address address mask
Parameter:
address |
Network
for summary. |
Mask |
Sub
network Mask of summarizing route. |
not-advertise |
(Optional) It is
used to restrain the generation of LSA from matched routes. |
Default:
none
Command mode:
route configuration mode
Explanation:
There can be groups of addresses to be summarized. The route
learned from other routing protocol can also be summarized. After being
summarized, all networks covered by it will not be transmitted to other route area.
The cost for the summary route is the smallest one among routes summarized.
This command can reduce the route number in the routing table.
Using this command for OSPF will cause
the OSPF autonomous system border router(ASBR) to inform an exterior route into OSPF domain for these routes
distributed from exterior networks covered by the network configured. This
command can only summarize routes entering into OSPF by redistributing from
other routing protocol. “area
range”
can be used to summarize routes in OSPF domain.
Example:
In
the following example, summarized address 10.1.0.0 represents 10.1.1.0, 10.1.2.0, 10.1.3.0,etc. only
address 10.1.0.0 is broadcasted.
summary-address 10.1.0.0 255.255.0.0
Relevant command:
area range
ip
ospf password
ip
ospf message-digest-key
Use
route configuration state command “timer
delay” to designate the time we could delay for SPF calculation after
receiving a topology change. Use command “no timers delay” to reset the default settings.
timers delay spf-delay
no timers delay
Parameter:
spf-delay |
Time delay in seconds between the
topology changing and SPF starting calculation. The range is from 0 to 65535.
Default value is 5 seconds. If it is 0 second, it means no time delay. Recalculate
at once if there is any change. |
Default:
spf-delay: 5 seconds
Command mode:
route configuration mode
Explanation:
The less the setting time is, the more quickly it reflects the change
of the network topology. But it will take more time of the processor.。
Example:
timers spf 10
Use route configuration command “timers
hold” to set interval between two sequential calculations for OSPF.
Use command “no timers spf” to reset the
default setting.。
timers hold spf-holdtime
no timers hold
Parameter:
spf-holdtime |
The smallest value between the two
sequential calculations. The range is from 0 to 65535. The default is 10
secnds. If it is 0, it means that there is no interval between the two
calculations. |
Default:
spf-holdtime: 10 seconds
Command mode:
route configuration mode
Explanation:
The less the setting time is, the more quickly to reflect the change
of the network topology. But it will take more time of the processor.
Example:
timers spf 20