CCIE Pursuit Blog

April 22, 2008

Status Update: 07 – 20 April

A month ago my preparation was zipping along.  Now I’m limping.  Life has conspired (as it has a way of doing) to completely screw up my last two weeks of training.  I’ve had to deal with taxes, a good friend leaving, helping another friend with emergency home repairs brought on by a flooded basement, a huge spike in workload, guarding our dock against icebergs, spring cleaning, garden/yard maintenance….blah blah blah.

I’ve not been able to do much in the way of studies.  I’ve belted out some hours on the CLI over the weekend, but they were pretty non-contiguous hours and not very productive.  I really cannot commit any time during the week due to domestic and work duties.  When my weekend hours are interrupted I pretty much lose the week for studying.

I have a mock lab scheduled for tomorrow.  I did well on the last mock lab, but I went into it after a long stretch of hardcore labbing.  I’m really not prepared for tomorrow’s lab.  There’s not much I can do but try to review some material tonight and tomorrow morning.

I’m thinking that I’m going to have to take some more time off from work and do another Labapolooza to get back on track.  I really want to get through all of the IE Volume II and III labs prior to my Mock Lab workshop.  I hate burning vacation time to do this.  I may have to attempt to cash in some “comp time”.  Whenever I work (significantly) over 40 hours a week or I get called in to troubleshoot an issue off hours (like the 12 hour debacle this weekend) I’m supposed to record that time and use it as comp(limentary?) time.  Supposedly I can use this time in lieu of vacation/PTO.  I say supposedly because I’ve never ‘cashed in’ comp time.  I rarely even track it.  We often joke about being able to take whole months off if we were accurately tracking and redeeming our comp hours.  🙂

Here are my goals from two weeks ago: Review BGP videos.  Finish Volume III lab 5.  Redo Volume II lab 10.  Start redoing the Volume I BGP labs.

I did manage to do all of this except the BGP labs.  I also redid Volume II lab 12.  I did not remember that I had done this lab before until I hit a question in OSPF that made me realize that this was my second time through this lab.  That’s a good thing in that I know that I can repeat labs because I definitely have not memorized them.  It’s bad because I could have used that time to knock out a different lab.

Here are my goals this week: Take IE Mock Lab 2.  Start redoing the Volume I BGP labs.  Complete one Volume II and one Volume III lab this weekend.

Days Until Lab: 90
Days Until Mock Lab 2: 1
Days Until Mock Lab Workshop: 55
Readiness (1 to 10): 6
Lab Hours This Week 8
Study Hours This Week (estimate): 4

Question Of The Day: 22 April, 2008

Topic: OSPF

Which ‘show’ command will give you detailed information about Type-5 LSAs you are receiving?

Click Here For The Answer


Yesterday’s Question

Question Of The Day: 21 April, 2008 

Topic: OSPF

Give two methods of introducing a default route into an OSPF NSSA.

Answer: ‘area nssa default-information-originate’ and ‘area nssa no-summary’

An OSPF NSSA (Not-So-Stubby-Area) will remove Type 5 LSAs while allowing redistribution into the area (Type 7 LSAs which are converted to Type 5 LSAs at the ABR).  The NSSA is the only OSPF stub area that does not originate a default route.  There are two methods to introduce a default route into an NSSA (both are configured on the ABR):

1) area 13 nssa default-information-originate
2) area 13 nssa no-summary

In this example, r1 is the ABR.  We’ve made area 13 an NSSA.  Now we want r1 to advertise a default route into the NSSA.

ABR:
r1
(config)#do sh ip os int br
Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C
Fa0/0        100   0               10.1.12.1/24       1     DR    1/1
Fa1/0        100   13              10.1.13.1/24       1     BDR   1/1

Stub:
r3(config-if)#do sh ip os int br
Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C
Fa0/0        100   13              10.1.13.3/24       1     DR    1/1

r3(config-if)#do sh ip route os
     100.0.0.0/32 is subnetted, 1 subnets
O IA    100.1.4.4 [110/4] via 10.1.13.1, 00:03:14, FastEthernet0/0
     10.0.0.0/24 is subnetted, 4 subnets
O IA    10.1.12.0 [110/2] via 10.1.13.1, 00:03:54, FastEthernet0/0
O IA    10.1.24.0 [110/3] via 10.1.13.1, 00:03:20, FastEthernet0/0
O IA    10.1.34.0 [110/4] via 10.1.13.1, 00:03:01, FastEthernet0/0

r3(config)#do show ip ospf database

            OSPF Router with ID (3.3.3.3) (Process ID 100)

                Router Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         11          0x80000006 0x0044A6 1
3.3.3.3         3.3.3.3         6           0x80000005 0x00C01C 1

                Net Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.13.1       1.1.1.1         12          0x80000001 0x00B74F

                Summary Net Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.12.0       1.1.1.1         46          0x80000001 0x000813
10.1.24.0       1.1.1.1         46          0x80000001 0x008D80
10.1.34.0       1.1.1.1         46          0x80000001 0x0029D9
100.1.4.4       1.1.1.1         46          0x80000001 0x00B50D

Method 1:
r1(config-router)#area 13 nssa default-information-originate

r3(config-if)#do sh ip route os           
     100.0.0.0/32 is subnetted, 1 subnets
O IA    100.1.4.4 [110/4] via 10.1.13.1, 00:06:06, FastEthernet0/0
     10.0.0.0/24 is subnetted, 4 subnets
O IA    10.1.12.0 [110/2] via 10.1.13.1, 00:06:45, FastEthernet0/0
O IA    10.1.24.0 [110/3] via 10.1.13.1, 00:06:11, FastEthernet0/0
O IA    10.1.34.0 [110/4] via 10.1.13.1, 00:05:52, FastEthernet0/0
O*N2 0.0.0.0/0 [110/1] via 10.1.13.1, 00:01:10, FastEthernet0/0
            
r3(config-if)#do show ip ospf database | b Type-7
                Type-7 AS External Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum Tag
0.0.0.0         1.1.1.1         84          0x80000001 0x002173 0

Note that the default route is advertised in a Type-7 LSA and that the IA routes are not filtered from the routing table.

Method 2:
r1
(config-router)#area 13 nssa no-summary

r3(config)#do sh ip route os
O*IA 0.0.0.0/0 [110/2] via 10.1.13.1, 00:00:46, FastEthernet0/0

r3(config)#do show ip ospf database

            OSPF Router with ID (3.3.3.3) (Process ID 100)

                Router Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         669         0x80000004 0x005C8E 1
3.3.3.3         3.3.3.3         672         0x80000004 0x00D605 1

                Net Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.13.3       3.3.3.3         672         0x80000001 0x0047B5

                Summary Net Link States (Area 13)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         1.1.1.1         77          0x80000001 0x001B17

Note that the OSPF IA routes are gone from the routing table.  We can see that the Summary Net Link States (LSA Type 3) are replaced with a default route.

When deciding between which method to use, look for phrase in the task like “introduce a default route but still allow inter-area routes to appear in the routing table” or “the default route should be advertised in a Type 7 LSA”.

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