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network cisco ccna gns3 certification arteq

network cisco ccna gns3 certification arteq
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Saturday, January 12, 2013

when i start getting far away...

i like to come back home...

jef doyle says:

Each Hello packet contains the following information:

Router ID of the originating router.
Area ID of the originating router interface.
Address mask of the originating interface.
Authentication type and authentication information for the originating interface.
HelloInterval of the originating interface.
RouterDeadInterval of the originating interface.
Router Priority.
DR and BDR.
Five flag bits signifying optional capabilities.
Router IDs of the originating router’s neighbors. This list contains only routers
from which Hellos were heard on the originating interface within the last
RouterDeadInterval.


is he correct?

R2#
*Jan 12 13:37:41.103: OSPF-1 PAK  : rcv. v:2 t:1 l:48 rid:1.1.1.1 aid:0.0.0.0 chk:D08F aut:0 auk: from FastEthernet0/0



the debug gives us version, type, length, router id, area id. checksum, auth type, auth key and that it was received on f0/0...

the capture does a little better...

it shows all doyle's stuff, but there are 8 options not 5...


i don't know about you but i never get sick of this shit...

a loopback interface is treated as a stub out of the box... when you issue the ip ospf network point-to-point statement on it, it becomes different...

R1(config-if)#do sh ip ospf int lo0
Loopback0 is up, line protocol is up
  Internet Address 1.1.1.1/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 1.1.1.1, Network Type LOOPBACK, Cost: 1
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1         no          no            Base
  Loopback interface is treated as a stub Host
 
R1(config-if)#ip ospf netw point-to-p
R1(config-if)#do sh ip ospf int lo0 
Loopback0 is up, line protocol is up
  Internet Address 1.1.1.1/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1         no          no            Base
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  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)
R1(config-if)#

if you make an area a stub on the abr, you better damn well include the router at the other end...

R2(config-router)#area 1 stub
R2(config-router)#
*Jan 12 13:59:47.075: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on FastEthernet0/1 from FULL to DOWN, Neighbor Down: Adjacency forced to reset

whoops...

R3(config)#router ospf 1
R3(config-router)#area 1 stub
R3(config-router)#
*Jan 12 14:02:44.599: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on FastEthernet0/1 from LOADING to FULL, Loading Done

that's better...

but to the abr, the only difference between the two is the subnet mask...

R2#sh ip ospf data router 1.1.1.1

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

        Router Link States (Area 0)

  LS age: 1549
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 1.1.1.1
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000007
  Checksum: 0x5D99
  Length: 48
  Number of Links: 2

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 1.1.1.0
     (Link Data) Network Mask: 255.255.255.0
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 10.1.1.1
     (Link Data) Router Interface address: 10.1.1.1
      Number of MTID metrics: 0
       TOS 0 Metrics: 1


R2#sh ip ospf data router 3.3.3.3

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

        Router Link States (Area 1)

  LS age: 60
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 3.3.3.3
  Advertising Router: 3.3.3.3
  LS Seq Number: 8000000E
  Checksum: 0x4EC9
  Length: 48
  Number of Links: 2

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 3.3.3.3
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.168.1.3
     (Link Data) Router Interface address: 192.168.1.3
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

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