OSPF củng cố kiến thức lại nào.

[phamminhtuan]

II. LSA loại 2
Do router DR phát ra.

R3#sh ip os database network

OSPF Router with ID (3.3.3.3) (Process ID 1)

Net Link States (Area 0)

Routing Bit Set on this LSA
LS age: 34
Options: (No TOS-capability, DC)
LS Type: Network Links
Link State ID: 192.168.1.3 (address of Designated Router) => cổng phát ra gói LSA loại 2
Advertising Router: 3.3.3.3 => Router ID của DR
LS Seq Number: 80000002
Checksum: 0x8D16
Length: 36
Network Mask: /24
Attached Router: 3.3.3.3
Attached Router: 1.1.1.1
Attached Router: 2.2.2.2
[3 dòng attached là số router gắn trực tiếp với nó là R1,R2 và chính nó]

Routing Bit Set on this LSA
LS age: 40
Options: (No TOS-capability, DC)
LS Type: Network Links
Link State ID: 192.168.15.2 (address of Designated Router)
Advertising Router: 5.5.5.5
LS Seq Number: 80000001
Checksum: 0xACE2
Length: 32
Network Mask: /24
Attached Router: 5.5.5.5
Attached Router: 2.2.2.2


Muốn xem interface nào tham gia và trở thành DR cho segment nào đó thì ta cũng dùng lệnh “show ip ospf interface”
R5#sh ip os interface
FastEthernet0/0 is up, line protocol is up
Internet Address 192.168.15.2/24, Area 0
Process ID 1, Router ID 5.5.5.5, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 5.5.5.5, Interface address 192.168.15.2
Backup Designated router (ID) 2.2.2.2, Interface address 192.168.15.1
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:02
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 2.2.2.2 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Loopback5 is up, line protocol is up
Internet Address 5.5.5.5/8, Area 0
Process ID 1, Router ID 5.5.5.5, Network Type LOOPBACK, Cost: 1
Loopback interface is treated as a stub Host

R3# sh ip os interface
FastEthernet1/1 is up, line protocol is up
Internet Address 192.168.1.3/24, Area 0
Process ID 1, Router ID 3.3.3.3, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 3.3.3.3, Interface address 192.168.1.3
Backup Designated router (ID) 2.2.2.2, Interface address 192.168.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:03
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 4
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 1.1.1.1
Adjacent with neighbor 2.2.2.2 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Loopback3 is up, line protocol is up
Internet Address 3.3.3.3/24, Area 0
Process ID 1, Router ID 3.3.3.3, Network Type LOOPBACK, Cost: 1
Loopback interface is treated as a stub Host



R1#sh ip os interface
FastEthernet0/0 is up, line protocol is up
Internet Address 192.168.1.1/24, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DROTHER, Priority 1
Designated Router (ID) 3.3.3.3, Interface address 192.168.1.3
Backup Designated router (ID) 2.2.2.2, Interface address 192.168.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:01
Index 3/3, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 2.2.2.2 (Backup Designated Router)
Adjacent with neighbor 3.3.3.3 (Designated Router)
Suppress hello for 0 neighbor(s)
FastEthernet1/0 is up, line protocol is up
Internet Address 172.16.1.1/16, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.1.1.1, Interface address 172.16.1.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:00
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
Loopback1 is up, line protocol is up
Internet Address 1.1.1.1/24, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type LOOPBACK, Cost: 1
Loopback interface is treated as a stub Host

Do đó một router có thể là DR cho mạng này nhưng lại có thể là BDR hoặc Drother cho mạng khác.
R2#sh ip os interface
FastEthernet0/0 is up, line protocol is up
Internet Address 192.168.15.1/24, Area 0
Process ID 1, Router ID 2.2.2.2, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 2.2.2.2, Interface address 192.168.15.1
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:00
Index 4/4, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
FastEthernet1/0 is up, line protocol is up
Internet Address 192.168.1.2/24, Area 0
Process ID 1, Router ID 2.2.2.2, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 3.3.3.3, Interface address 192.168.1.3
Backup Designated router (ID) 2.2.2.2, Interface address 192.168.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:00
Index 3/3, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 1.1.1.1
Adjacent with neighbor 3.3.3.3 (Designated Router)
Suppress hello for 0 neighbor(s)
Serial2/2 is up, line protocol is down
Internet Address 192.1.1.1/24, Area 0
Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
Transmit Delay is 1 sec, State DOWN,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Loopback1 is up, line protocol is up
Internet Address 2.2.2.2/8, Area 0
Process ID 1, Router ID 2.2.2.2, Network Type LOOPBACK, Cost: 1
Loopback interface is treated as a stub Host