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Hi ,

good exercise, however I think its important to point out that without

ip summary-address eigrp 100 0.0.0.0 0.0.0.0

which was configured on the frame relay interface of R4 in the previous exercise 5.9 then this would not work!

ignore this, sorry

1) For this exercise, can someone please explain to me why is it that before you apply the commands in 5.10, if you do a traceroute to 150.1.4.4, it will traverse the frame relay cloud, through R1 and then to R4's interface on VLAN 146 then go to the loopback? According to the solutions, it should traverse through 155.1.0.4.

R5#traceroute 150.1.4.4

Type escape sequence to abort.
Tracing the route to 150.1.4.4

  1 155.1.0.1 4 msec 4 msec 4 msec
  2 155.1.146.4 4 msec *  0 msec

2) I'm still confused on what exactly leakmap does. In addition, how does configuring a leakmap allow traffic to be re-routed across the frame-relay network if the P2P link goes down? It seems like it would do that anyway even without Leakmap.

Thanks.

Hello jasonwa,

Make sure you read the topic of route summarization with EIGRP. EIGRP summary suppresses all subnets that make up the summary from being advertized - meaning only the summary is being sent out in the advertisement – by design, this was meant to reduce the size of the routing tables.

To answer your question - note that the 5.10 is tied to 5.9.

In 5.9, you configured the summarization with default routing.
This is how the routing table on R5 looks after - for the routes going to R4 as next hop:

Rack1R5#sh ip route | include via 155.1.(0|45).4
D*   0.0.0.0/0 [90/2297856] via 155.1.45.4, 00:02:42, Serial0/1
               [90/2297856] via 155.1.0.4, 00:02:42, Serial0/0

As you have noted there are 2 paths - one via the frame relay and the other via the point-to-point serial.

After completing 5.10, you will note the following in the routing table of R5:

Rack1R5#sh ip route | include via 155.1.(0|45).4
D       150.1.4.0 [90/2297856] via 155.1.45.4, 00:01:10, Serial0/1
D*   0.0.0.0/0 [90/2297856] via 155.1.45.4, 00:01:10, Serial0/1
               [90/2297856] via 155.1.0.4, 00:01:10, Serial0/0

The leak-map allows R4 to leak the route to its loopback0 via the point-to-point serial – along with the summary route; with that being the longest match R5 will use the point-to-point serial to send traffic destined to R4 loopback0.

HTH,

Maindor

I'm doing LAB in Dynagen.

I tried different scenario with sub-interface s0/0.1 (facing to Frame-Relay) and it seems not support command "ip summ ei 100 0.0.0.0 0.0.0.0 leak-map"

Could anyone explain this?

Thanks in advanced!

ariste999:

I'm doing LAB in Dynagen.

I tried different scenario with sub-interface s0/0.1 (facing to Frame-Relay) and it seems not support command "ip summ ei 100 0.0.0.0 0.0.0.0 leak-map"

Could anyone explain this?

Thanks in advanced!

Change your IOS image file to a 12.4 one and it will work.

Thanks for explanation Maindor,

So as i understand leak-map simply allow neighbors to recieve other then 0.0.0.0 routes leaked routes like 150.1.4.0.

Without leak-map we would not be able to specify which exact interface should 150.1.4.0 be routed on, correct ?

unsobill:

Thanks for explanation Maindor,

So as i understand leak-map simply allow neighbors to recieve other then 0.0.0.0 routes leaked routes like 150.1.4.0.

Without leak-map we would not be able to specify which exact interface should 150.1.4.0 be routed on, correct ?

Hi unsobill,

That is correct; when you use the summary-address it will summarize all the specific routes and generate only a default route. The leak-map will allow you to leak some specific routes. It is very useful for traffic engineering purposes.

Good luck!