Re: EIGRP Traffic Share Count

Hello again,

Garth has provided a valuable resource to calculate Traffic Share and detail
about load sharing. Can anyone else, please provide more understanding on
how to calculate share based on examples as I am having difficulty
understanding nuts and bolts of Traffic Share Count.

Thanks everyone -

Regards,
Bilal

On Sun, Sep 26, 2010 at 11:42 PM, Bilal Hansrod
<bilal.hansrod_at_gmail.com>wrote:

> Thanks Garth, but still I am trying to understand Traffic Share Count value
> arrived via calculation. How did you get 120 via 155.1.67.7 and 103
> via 155.1.146.1 (please see below output from show ip route 155.1.9.9).
> There is a lab in INE W1 and it asks to change the traffic share to 1:5 and
> uses the formula:
>
> INE Task 5.15 EIGRP Unequal Cost Load Balancing
>
> "These paths are now balanced 103:120. To achieve the desired 1:5 traffic
> share,
> R6s delay on the link to R1 must be updated. The actual values used on R1,
> R3, and R6 for delay can have multiple valid options as long as two
> conditions
> are true. First, the Advertised Distance R1 sends to R6 must be lower than
> R6s
> Feasible Distance. Secondly the entire composite result R6 calculates
> through
> R1 should be five times the Feasible Distance.
> In our case R1s Advertised Distance is 40 microseconds, or 4 tens of
> microseconds. This specifically means the following must be true if we want
> a
> traffic share of 1:5.
> 3072 * 5 = (R6_TO_R1_DLY + 4) * 256
> Therefore R6s delay to R1 should be 56 tens of microseconds."
>
>
>
>
>
>
> On Sun, Sep 26, 2010 at 10:29 PM, Garth Bryden <
> hacked.the.planet.on.28.8k.dialup_at_gmail.com> wrote:
>
>> Hi Bilal,
>>
>> You want to read this post-
>>
http://blog.ine.com/2009/05/01/understanding-unequal-cost-load-balancing/..
>> This has an explanation on the traffic share ratio you are seeing above.
>>
>> I think the answer you seek though is
>>
>> EIGRP will divide each links metric by the largest paths metric..
>>
>> 3584 / 3072 which is 1.166
>> 3584 / 3584 which is 1
>>
>> FYI- 120 / 103 = 1.165
>>
>> EIGRP will round down to the nearest integer so the first path is actually
>> "1"
>>
>> I also believe the largest metric would have be a path being selected by
>> EIGRP for placement into the routing table.. If your route is not selected
>> because the metric is larger than the
>> Variance x feasible distance.. I do not believe it will be included in
>> the route traffic share calculation.
>>
>> HTH
>>
>> Garth
>>
>>
>>
>> On Sun, Sep 26, 2010 at 6:14 PM, Bilal Hansrod
<bilal.hansrod_at_gmail.com>wrote:
>>
>>> Hello Everyone,
>>>
>>> I am having difficulty calculating the EIGRP Traffic Share Count. As far
>>> as
>>> my understanding regarding Traffic Share Count is, you divide the largest
>>> metric with lowest to forward packets based on number. For example
>>>
>>> A-X = Metric is 10
>>> B-X = Metric is 20
>>> C-X = Metric is 30
>>> D-X = Metric is 40
>>> E-X = Metric is 90
>>>
>>> If I configure variance 4, it means all above metric will be used for
>>> load
>>> balancing except E-X (90), because it does not fall under 80 (Lowest
>>> Metric
>>> X 4). So when calculate, I still use E-X Metric for Traffic Share Count.
>>>
>>>
>>> A-X = Metric is 10 = Traffic Share Count (90/10) = 9
>>> B-X = Metric is 20 = Traffic Share Count (90/20) = 5
>>> C-X = Metric is 30 = Traffic Share Count (90/30) = 3
>>> D-X = Metric is 40 = Traffic Share Count (90/40) = 2
>>>
>>> It means 9 packets will be sent via A-X, 5 packets via B-X, 3 packets via
>>> C-X, and 2 packets via D-X and round robin. Am I correct till here??
>>>
>>> Now, when I have below output, how is Traffic Share Count calculated
>>>
>>> Rack1R6#show ip route 155.1.9.9
>>> Routing entry for 155.1.9.0/24
>>> Known via "eigrp 100", distance 90, metric 3072, type internal
>>> Redistributing via eigrp 10, eigrp 100
>>> Advertised by eigrp 10
>>> Last update from 155.1.146.1 on FastEthernet0/0.146, 00:01:04 ago
>>> Routing Descriptor Blocks:
>>> 155.1.146.1, from 155.1.146.1, 00:01:04 ago, via FastEthernet0/0.146
>>> Route metric is 3584, traffic share count is 103
>>> Total delay is 140 microseconds, minimum bandwidth is 1544 Kbit
>>> Reliability 255/255, minimum MTU 1500 bytes
>>> Loading 1/255, Hops 4
>>>
>>> * 155.1.67.7, from 155.1.67.7, 00:01:04 ago, via FastEthernet0/0.67
>>> Route metric is 3072, traffic share count is 120
>>> Total delay is 120 microseconds, minimum bandwidth is 100000 Kbit
>>> Reliability 255/255, minimum MTU 1500 bytes
>>> Loading 1/255, Hops 2
>>>
>>>
>>> Anyone's help will be highly appreciated,
>>>
>>> Regards,
>>>
>>> Bilal
>>>
>>>
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Received on Mon Sep 27 2010 - 10:44:49 ART