CCIE Pursuit Blog

August 16, 2008

Internetwork Expert Volume II: Lab 8 – Section 3

Section 3 – Interior Gateway Routing – 16 Points

3.1 OSPF

Simple OSPF task.  The only odd bit is that you’ll be configuring OSPF over the PPPoFR network.  It makes sense that the OSPF network type is point-to-point.  🙂

r3(config-router)#do sh ip os int | i proto|Type
is up, line protocol is up
  Process ID 100, Router ID, Network Type POINT_TO_POINT, Cost: 1

r2#sh ip os nei

Neighbor ID     Pri   State           Dead Time   Address         Interface         0   FULL/  –        00:00:38      Multilink1

“Authenticate the OSPF adjacency between r2 and r6 using OSPF type 1 authentication.”

Crap.  I think that type 1 is just clear-text (type 0 = null and type 7 = md5).  It’s weird that the task does not mention a password.  I used the old standby of “CISCO”

r6(config-router)#int FastEthernet0/1.26
r6(config-subif)#ip ospf authentication
r6(config-subif)#ip ospf authentication-key CISCO

r2(config-subif)#do sh ip os int Gi0/0.26 | i proto|authe
GigabitEthernet0/0.26 is up, line protocol is up
  Simple password authentication enabled 

3.2 OSPF

Configure area 38 so that “external LSAs” are not advertised in.

We know that we’re done to stub or totally stubby at this point.

“Ensure that devices in OSPF area 38 still have specific forwarding information about prefixes originated in other OSPF areas.”

So we need to allow IA routes (LSA 3).  That sounds like a stub area to me.

3.3 OSPF

Create area 67 and then summarize and with no overlapping address space:

7 0000011|1
6 0000011|0 or

Summary will move from area to area so use…..area range.  🙂

r6(config)#router os 100
r6(config-router)#area 67 range

r3#sh ip route
Routing entry for
  Known via “ospf 100”, distance 110, metric 3, type inter area
  Last update from on Multilink1, 00:00:36 ago
  Routing Descriptor Blocks:
  *, from, 00:00:36 ago, via Multilink1
      Route metric is 3, traffic share count is 1

r3#sh ip route
Routing entry for

  Known via “ospf 100”, distance 110, metric 3, type inter area
  Last update from on Multilink1, 00:00:50 ago
  Routing Descriptor Blocks:
  *, from, 00:00:50 ago, via Multilink1
      Route metric is 3, traffic share count is 1


Basic EIGRP task.  The only confusing bit is that the task asks you to advertise the lo0 interface of all of the EIGRP devices into EIGRP.  r3 is already advertising its lo0 interface into OSPF.  They must have meant all of the EIGRP devices except r3 (the solution guide bears this out).

Remember to disable split-horizon on the Frame Relay hub (r1):

r1(config-router)#int s0/0
r1(config-if)#no ip split-horizon eigrp 1024

3.5 RIP

Easy RIP task with authentication.

3.6 IGP Redistribution

Redistribute between RIP and EIGRP on r5 and then between OSPF and EIGRP where needed.

Remember that OSPF area 38 is a stub area so it’s not going to let in any external routes.  That means our OSPF<->EIGRP redistribution needs to happen on r3.

I ran into one issue.  I had a route to on r1 (connected) as well as r2-3(OSPF).  But r4 and r5 did not have the route.

The problem is that r3 gets that route via OSPF and then advertises it to r1.  R1 does not install the route from r3 because it has that network as connected.  The route does not get passed on to the EIGRP routers behind r1.

I need to either redistribute that connected interface into EIGRP on r1 or find some way to have r1 prefer the route to r3 over the connected route.

r1(config)#route-map CONN->EIGRP
r1(config-route-map)#match int Fa0/0.13

r1(config-route-map)#router ei 1024
r1(config-router)#redist conn met 1 1 1 1 1 route-map CONN->EIGRP

r4#sh ip route
Routing entry for

  Known via “eigrp 1024”, distance 170, metric 2560512256, type external
  Redistributing via eigrp 1024
  Last update from on Serial0/0, 00:00:30 ago
  Routing Descriptor Blocks:
  *, from, 00:00:30 ago, via Serial0/0
      Route metric is 2560512256, traffic share count is 1
      Total delay is 20010 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1


Type escape sequence to abort.
Tracing the route to

  1 4 msec *  4 msec

I ended up with full reachability by only redistributing RIP<->EIGRP on r5, OSPF<->EIGRP on r3, and Connected (fa0/0.13) -> EIGRP on r1.

IE went a different route.  Then redistributed OSPF->EIGRP on r1, OSPF<->EIGRP on r3, as well as RIP<->EIGRP on r5.

3.7 Load Distribution

Configure the network so that traffic from r4 to r5 is distributed in a 4:1 ratio between the Ethernet connection and the Frame Relay connection.

I messed with this for tooooooooo long.  I tried messing with the metric weight and I was still mindfucked.  I’ll just eat the 3 points and move on.


I have to try this tomorrow:

Becoming a CCIE: EIGRP Unequal path load balancing


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