OSPF Open Shortest Path First
OSPF
.
. shortest-path tree,
.
.
Link State Advertise(LSA)-
. LSA
30 . LSA
.
RIP (routed) - ,
30 .
.
IGRP - , ,
"" , ,
CISCO-.
Link-state .
VLSM - Variable Length Subnet Mask. - .
A,B,C ,
VSML.
OSPF .
.
Areas - "areas" -
.
.
.
OSPF ID.
LSA - Link State Advertisment.
Hello protocol
multicast-
Types LSAs
LSM
, OSPF.
.
- IP- .
LSA - Link State Advertisment
LSA - ,
.
.
LSA ,
, SFP-
LSA .
LSA .
( )
30 . ( )
:
---------------------------------------------------------------
Router# show ip ospf database
OSPF Router with id(192.168.239.66) (Autonomous system 300)
Displaying Router Link States(Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link count
172.18.21.6 172.18.21.6 1731 0x80002CFB 0x69BC 8
172.18.21.5 172.18.21.5 1112 0x800009D2 0xA2B8 5
172.18.1.2 172.18.1.2 1662 0x80000A98 0x4CB6 9
172.18.1.1 172.18.1.1 1115 0x800009B6 0x5F2C 1
172.18.1.5 172.18.1.5 1691 0x80002BC 0x2A1A 5
Displaying Net Link States(Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
172.18.1.3 192.20.239.66 1245 0x800000EC 0x82E
Displaying Summary Net Link States(Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
172.18.240.0 172.18.241.5 1152 0x80000077 0x7A05
172.18.241.0 172.18.241.5 1152 0x80000070 0xAEB7
172.18.244.0 172.18.241.5 1152 0x80000071 0x95CB
LSA
.
---------------------------------------------------------------
Point-to-Point - -
"-"
Multiaccess - Hello protocol
(. ethernet, Designate Router ( )
FDDI)
Nonbroadcast -
Multiaccess OSPF
(. Frame relay,
X.25)
multicast- LSA-
- . "" LSA
Designed Router'(DR). DR
LSA "".
DR Hello. Hello
multicast 224.0.0.5.
Backup Designate Routera (BDR) -
. DR
LSA . DR
BDR.
router LSA DR' (
DR+BDR) multicast 224.0.0.6
DR LSA "" multicast
224.0.0.5
:
---------------------------------------------------------------
Router# debug ip osfp events
Router (config-if)# shutdown
! ""
LSA
Router (config-if)# no shutdown
! ""
LSA
---------------------------------------------------------------
OSPF
, area (?)
Area Border Router (ABR) - ,
area.
.
Internal router -
, area.
.
Backbone router -
Autonomous System Boundary router -
,
OSPF
---------------------------------------------------------------
Router# router ospf process-id
---------------------------------------------------------------
process-id -
. OSPF
""
process-id
, OSPF
---------------------------------------------------------------
Router# network netaddress wildcard-mask area area-id
---------------------------------------------------------------
netaddress
wildcard-mask
( -
OSPF )
area-id , area
---------------------------------------------------------------
router ospf 63
network 1.0.0.0 0.255.255.255 area 0
---------------------------------------------------------------
---------------------------------------------------------------
interface e 0
ip address 131.108.25.1 255.255.255.0
interface e 1
ip address 131.108.2.26 255.255.255.0
interface e 2
ip address 131.108.3.7 255.255.255.0
interface loopback 0
ip address 3.3.3.3 255.0.0.0
---------------------------------------------------------------
1
OSPF
router ospf 63
network 131.108.25.1 0.0.0.0 area 0
network 131.108.3.7 0.0.0.0 area 0
network 131.108.2.26 0.0.0.0 area 0
2
OSPF ,
router ospf 63
network 131.108.0.0 0.0.255.255 area 0
3
OSPF , .. loopback-
router ospf 63
network 0.0.0.0 255.255.255.255 area 0
---------------------------------------------------------------
network 131.108.25.1 0.0.0.255 area 0
network 131.108.0.0 0.0.255.255 area 34
---------------------------------------------------------------
(e0) (1 + 3) ""
area. 131.108.25.1 131.108.0.0,
.
Link State Andvertisement
Router LSA
-area
SPF
"O" (OSPF derived router)
Summary LSA
Area Border
"IA" (Inter Area routes)
---------------------------------------------------------------
Roter# show ip ospf
Routing Process "ospf 201" with ID 192.168.110.200
Supports only single TOS(TOS0) route
It is an area border and autonomous system boundary router
Summary Link update interval is 0:30:00 and the update due in 0:16:26
External Link update interval is 0:30:00 and the update due in 0:16:27
Redistributing External Routes from,
igrp 200 with metric mapped to 2, includes subnets in redistribution
rip with metric mapped to 2
igrp 2 with metric mapped to 100
igrp 32 with metric mapped to 1
Number of areas in this access server is 3
Area 192.168.110.0
Number of interfaces in this area is 1
Area has simple password authentication
SPF algorithm executed 6 times
Area ranges are
Link State Update Interval is 0:30:00 and due in 0:16:55
Link State Age Interval is 0:20:00 and due in 0:06:55
---------------------------------------------------------------
"O" - OSPF derived router (Router LSA)
"IA" - Inter Area routes (Summary LSA)
"E1" - Type-1 External Routes
"E2" - Type-2 External Routes
E1
E2
(..
area
broadcast' (. frame-relay, X.25),
"" OSPF
:
---------------------------------------------------------------
router ospf
neighbor 172.16.3.4 priority 1 poll-interval 180
---------------------------------------------------------------
B
---------------------------------------------------------------
131.108.4.0 255.255.252.0
131.108.8.0 255.255.252.0
131.108.12.0 255.255.252.0
~~~~~~~~~
131.108.16.0 255.255.252.0
. . .
131.108.28.0 255.255.252.0
~~~~~~~~~
||
\/
131.108.16.0 255.255.240.0
---------------------------------------------------------------
, () -
.
( )
~~~~~~~~~
131.108.12.0 255.255.252.0
~~~~~~~~~
||
\/
131.108.12.0 255.255.240.0
131.108.8.0 255.255.252.0
0- .
---------------------------------------------------------------
Route# area area-id range address mask
---------------------------------------------------------------
---------------------------------------------------------------
router ospf 63
network 1.0.0.0 0.255.255.255 area 0
network 2.0.0.0 0.255.255.255 area 2
area 0 range 1.0.0.0 255.0.0.0
area 2 range 2.0.0.0 255.0.0.0
router ospf 63
network 1.0.0.0 0.255.255.255 area 0
network 3.0.0.0 0.255.255.255 area 3
area 0 range 1.0.0.0 255.0.0.0
area 3 range 3.0.0.0 255.0.0.0
---------------------------------------------------------------
---------------------------------------------------------------
Route# show ip protocols
. . .
Routing Protocol is "ospf 109"
Sending updates every ?? seconds, next due in ?? seconds
Invalid after ??? seconds, hold down 280, flushed after 630
. . .
---------------------------------------------------------------
CISCO-router ----- > non-CISCO-router
---------------------------------------------------------------
Router (config-if)# ip ospf cost cost
---------------------------------------------------------------
Cisco-
(bandwidth). OSPF
.
ip osf cost
area authentication
area virtual-link
default-information originate (OSPF)
default-metric (BGP, EGP, OSPF, and RIP)
ip ospf authentication-key
ip ospf cost
ip ospf dead-interval
ip ospf hello-interval
ip ospf message-digest-key
ip ospf network
ip ospf priority
ip ospf retransmit-interval
ip ospf transmit-delay
ip ospf-name-lookup
match route-type
network area
neighbor (OSPF)
ospf auto-cost-determination
router ospf
redistribute
set metric-type
show ip ospf
show ip ospf border-routers
show ip ospf database
show ip ospf interface
show ip ospf neighbor
show ip ospf virtual-links
Last-modified: Tue, 03 Mar 1998 21:31:29 GMT