From: Todd.Osterberg@compucom.com
Date: Mon Apr 03 2006 - 14:39:54 GMT-3
I was working on this same lab as well. I have a mix of 10mb and 100Mb
e's and as such, the EIGRP metric calculation on my rack is different
that that listed in the lab solution guide.
Here is the EIGRP formula:
metric = [K1*bandwidth + (K2*bandwidth)/(256 - load) + K3*delay] *
[K5/(reliability + K4)]
Before any configuration is applied, you need to look at the metrics
that are being advertised to R4 for any of the routes from bb2. I chose
to look at 222.22.22.0.
Rack1R4#sh ip rou 222.22.2.0
Routing entry for 222.22.2.0/24
Known via "eigrp 1024", distance 170, metric 3242752, type external
Redistributing via eigrp 1024
Last update from 174.1.145.1 on Serial1/0, 1d17h ago
Routing Descriptor Blocks:
* 174.1.45.5, from 174.1.45.5, 1d17h ago, via Ethernet1/0
Route metric is 3242752, traffic share count is 1
Total delay is 60010 microseconds, minimum bandwidth is 1500 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1
What is important to solving this question is the metric of 3242752.
You need to modify the metric of the required routes that r4 is learning
via s0/0.
Next, you need to identify the metric of the route that is NOT being
installed into the routing table. The EIGRP topology table will have
this info. You should see that the there are two table entries for the
routes in question. You must then modify the inputs to the EIGRP
calculation so that the e0/0 routes have a metric that is 4 times
smaller than the s0/0 routes plus configure the router to perform
unequal load balancing.
I ended up 'throwing mud' until some of it stuck and I ended up with the
desired results. In retrospect, I could have gone through the process
of performing the eigrp calculation but since time is of the essence, I
think the 'mud' method works well in this case. As you are working
through ths configuration, remember that it does take a few seconds for
the results of the configuration change to be reflected. Don't get
over-anxious to see the results. Here is what I ended up with in my
configuration on R4:
interface Ethernet0/1
ip address 174.1.45.4 255.255.255.0
delay 6000
half-duplex
end
interface Serial1/0
ip address 174.1.145.4 255.255.255.0
encapsulation frame-relay
delay 43800
frame-relay map ip 174.1.145.1 401 broadcast
frame-relay map ip 174.1.145.5 401
no frame-relay inverse-arp
end
Additionally, I did configure R5 s0/0 and r1 s0/0 with a delay of 1.
Here is what I used to verify that my configuration was working
properly:
Rack1R4#sh ip rou 222.22.2.0
Routing entry for 222.22.2.0/24
Known via "eigrp 1024", distance 170, metric 3242752, type external
Redistributing via eigrp 1024
Last update from 174.1.145.1 on Serial1/0, 1d18h ago
Routing Descriptor Blocks:
* 174.1.45.5, from 174.1.45.5, 1d18h ago, via Ethernet1/0
Route metric is 3242752, traffic share count is 4
Total delay is 60010 microseconds, minimum bandwidth is 1500 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1
174.1.145.1, from 174.1.145.1, 1d18h ago, via Serial1/0
Route metric is 12919808, traffic share count is 1
Total delay is 438020 microseconds, minimum bandwidth is 1500 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 2
Rack1R4#sh ip eigrp topology 222.22.2.0
IP-EIGRP (AS 1024): Topology entry for 222.22.2.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is
1732352
Routing Descriptor Blocks:
174.1.45.5 (Ethernet1/0), from 174.1.45.5, Send flag is 0x0
Composite metric is (3242752/1706752), Route is External
Vector metric:
Minimum bandwidth is 1500 Kbit
Total delay is 60010 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
External data:
Originating router is 150.1.5.5
AS number of route is 0
External protocol is RIP, external metric is 7
Administrator tag is 0 (0x00000000)
174.1.145.1 (Serial1/0), from 174.1.145.1, Send flag is 0x0
Composite metric is (12919808/1707008), Route is External
Vector metric:
Minimum bandwidth is 1500 Kbit
Total delay is 438020 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
External data:
Originating router is 150.1.5.5
AS number of route is 0
External protocol is RIP, external metric is 7
Administrator tag is 0 (0x00000000)
Rack1R4#
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Aristomenis Zikopoulos
Sent: Monday, April 03, 2006 3:52 AM
To: ccielab@groupstudy.com; nobody@groupstudy.com
Subject: IEV3 Lab 8 Section 3.7 , Variance
Hello,
IEV3 Lab 8 Section 3.7
3.7 Load Distribution
Traffic from R4 should be distributed between Eth and FR links in a
ratio of
4:1.
I would like to know how the numbers for the delay configuration were
derived. I know that it said in the solution guide to do a
"show ip ro BB2_subnet", and check the traffic share count, but the
numbers
still don't make sense to me.
Any guidance will be appreciated.
Best Regards,
Aris
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