OSPF discontigous

TH1: discontigous Non-AREA. Tat ca cac area phai ket noi toi backboon area.

QUIZ: R3 k phai la ABR nen no se k tao ra LSA type 3 giua AREA 1 va AREA 2. vi vay R2 se k biet den mang 4.4.4.0/24 va k co trong database

R3#show ip os da

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

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum

1.1.1.0         2.2.2.2         535         0x80000001 0x00978F

10.1.12.0       2.2.2.2         586         0x80000001 0x009E75

                Router Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum Link count

3.3.3.3         3.3.3.3         519         0x80000004 0x00741F 2

4.4.4.4         4.4.4.4         521         0x80000004 0x005A2D 2

                Net Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum

10.1.34.4       4.4.4.4         521         0x80000001 0x0018C4

• Solution:  tao virtual-link hoac GRE tunnel giua R2 va R3

TH2: discontigous area 0 in ospf

QUIZ: R2 là ABR nó sẽ không đưa inter-area routes ( area 0 giua R3-R4) mà nhận được từ non-backbone interface (interface f0/1) lên bảng định tuyến, mặc dù có trong database

R2#show ip route 4.4.4.0

% Network not in table

R2#show ip os da su 4.4.4.0

            OSPF Router with ID (2.2.2.2) (Process ID 1)

                Summary Net Link States (Area 1)

  LS age: 86

  Options: (No TOS-capability, DC, Upward)

  LS Type: Summary Links(Network)

  Link State ID: 4.4.4.0 (summary Network Number)

  Advertising Router: 3.3.3.3

  LS Seq Number: 80000001

  Checksum: 0xD0D

  Length: 28

  Network Mask: /24

        TOS: 0  Metric: 11

• Solution: tao virtual-link hoac GRE tunnel giua R2-R3