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network cisco ccna gns3 certification arteq

network cisco ccna gns3 certification arteq
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Sunday, November 25, 2012

area types and lsa's part deux...

continuing from the last post...


basic... rip and ospf haven't been redistributed yet, and nssa is not yet in effect...

r4#sh ip ospf data

            OSPF Router with ID (4.4.4.4) (Process ID 1)

        Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         444         0x80000002 0x0061A3 1
3.3.3.3         3.3.3.3         240         0x80000005 0x009413 3
4.4.4.4         4.4.4.4         229         0x80000003 0x00F5D4 2

        Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.2.1        2.2.2.2         444         0x80000001 0x008F80
10.1.4.3        3.3.3.3         240         0x80000001 0x009B64

        Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
2.2.2.2         2.2.2.2         586         0x80000001 0x00FA31
10.1.1.0        2.2.2.2         606         0x80000001 0x00BD6A
r4#

lsa types 1,2 and 3 are represented on r4, as expected...


we'll first redist rip and ospf...

 r4#sh ip ospf data

            OSPF Router with ID (4.4.4.4) (Process ID 1)

        Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         41          0x80000005 0x00619E 1
3.3.3.3         3.3.3.3         1359        0x80000005 0x009413 3
4.4.4.4         4.4.4.4         67          0x80000005 0x00F1D6 2

        Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.2.1        2.2.2.2         1562        0x80000001 0x008F80
10.1.4.3        3.3.3.3         1358        0x80000001 0x009B64

        Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
2.2.2.2         2.2.2.2         1704        0x80000001 0x00FA31
10.1.1.0        2.2.2.2         1724        0x80000001 0x00BD6A

        Type-5 AS External Link States
          
Link ID         ADV Router      Age         Seq#       Checksum Tag
1.0.0.0         2.2.2.2         40          0x80000001 0x003456 0
r4#

now we have the expected external type on r4...

and for completeness, rip has picked up some new friends...

rip#sh ip route rip

Gateway of last resort is not set

R     2.0.0.0/8 [120/5] via 10.1.1.2, 00:00:27, FastEthernet0/0
R     3.0.0.0/8 [120/5] via 10.1.1.2, 00:00:27, FastEthernet0/0
R     4.0.0.0/8 [120/5] via 10.1.1.2, 00:00:27, FastEthernet0/0
      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
R        10.1.2.0/24 [120/1] via 10.1.1.2, 00:00:27, FastEthernet0/0
R        10.1.4.0/24 [120/5] via 10.1.1.2, 00:00:27, FastEthernet0/0

back to stubs...

to make area 1 a stub include the abr (in this case the bb or r1) and r3... the rule is that all routers in stub areas participate in being stubs... in other words, if we simply made r3 a stub, it would  lose it's adjacency...

r2#sh ip ospf
omitted
 Area 1
        Number of interfaces in this area is 1
        It is a stub area

r3 has it's adjacency to r1 but no longer has type 5's...

r3#sh ip ospf data

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

        Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         533         0x80000007 0x008976 1
3.3.3.3         3.3.3.3         532         0x80000008 0x0018A0 3
4.4.4.4         4.4.4.4         1273        0x80000005 0x00F1D6 2

        Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.2.3        3.3.3.3         532         0x80000001 0x006BA0

        Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         2.2.2.2         537         0x80000001 0x0075C0
2.2.2.2         2.2.2.2         537         0x80000003 0x001517
10.1.1.0        2.2.2.2         537         0x80000003 0x00D750

make area 1 totally stubby by adding no-summary to r2...

on r2 sh ip ospf:

Area 1
        Number of interfaces in this area is 1
        It is a stub area, no summary LSA in this area
        Generates stub default route with cost 1

r3#sh ip ospf data

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

        Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         847         0x80000007 0x008976 1
3.3.3.3         3.3.3.3         846         0x80000008 0x0018A0 3
4.4.4.4         4.4.4.4         1587        0x80000005 0x00F1D6 2

        Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.2.3        3.3.3.3         846         0x80000001 0x006BA0

        Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         2.2.2.2         163         0x80000003 0x0071C2

change to nssa on r2 and r3 and we have:

r3#sh ip ospf data

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

        Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         21          0x8000000B 0x000FE2 1
3.3.3.3         3.3.3.3         20          0x8000000C 0x009715 3
4.4.4.4         4.4.4.4         95          0x80000007 0x0004C1 2

        Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.2.3        3.3.3.3         15          0x80000005 0x00EA15
10.1.4.4        4.4.4.4         95          0x80000001 0x006397

        Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
2.2.2.2         2.2.2.2         22          0x80000004 0x009A88
10.1.1.0        2.2.2.2         22          0x80000004 0x005DC1

        Type-7 AS External Link States (Area 1)
         
Link ID         ADV Router      Age         Seq#       Checksum Tag
1.0.0.0         2.2.2.2         21          0x80000001 0x008213 0



just like in the stub scenario, r4 will have to become an nssa also to particpate... all routers in the area...

r4(config-router)#no area 1 nssa
r4(config-router)#
*Nov 25 14:40:10.931: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Adjacency forced to reset

add area 1 nssa no-summary to r2 and:

r3#sh ip ospf data

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

        Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         186         0x8000000C 0x000DE3 1
3.3.3.3         3.3.3.3         96          0x80000010 0x007E15 3
4.4.4.4         4.4.4.4         97          0x8000000B 0x00A11A 2

        Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.2.3        3.3.3.3         544         0x80000005 0x00EA15
10.1.4.4        4.4.4.4         93          0x80000005 0x0001EF

        Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         2.2.2.2         14          0x80000001 0x00FC31

        Type-7 AS External Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Tag
1.0.0.0         2.2.2.2         550         0x80000001 0x008213 0

on r2:

 Area 1
        Number of interfaces in this area is 1
        It is a NSSA area
        Perform type-7/type-5 LSA translation


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