Task 3.2 - Load Distribution

When calculating the delay for R2

 

DLY (usec-R2) = 200480 >> Delay for R2 is in "usec"

Rack1R2#sh ip eigrp topology 164.1.26.0 255.255.255.0
IP-EIGRP (AS 100): Topology entry for 164.1.26.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 28160
  Routing Descriptor Blocks:
  0.0.0.0 (FastEthernet0/0), from Connected, Send flag is 0x0
      Composite metric is (28160/0), Route is Internal
      Vector metric:
        Minimum bandwidth is 100000 Kbit
        Total delay is 100 microseconds

R1 local delay to R2 = 200480 usec - 100 msec

shouldnt it become  (since 1msec > 1000usec)

R1 local delay to R2 = 200.480 msec - 100 msec

                             = 100.480 msec?

 

SG is using (200480 - 100). or 20038 tens of microseconds

Comments

  • I dont quite getting the point of the question :) As a matter of fact, usec (microsecond) is 1/1000 of millisecond. The confusing thing is that they use different units everywhere :)

  • I think the better/faster solution is not to fiddle with the delay at all. You can just set 'metric weights 0 1 0 0 0 0' and now you just rely on the bandwidth. The bandwidth is already at a ratio of 5:1 (1280k:256k). The variance will have to be set to 6 tho...

    But it's a good task on metric tweaking.

     

  • I think the tricky part is that "sh ip ro 164.1.26.0", shows the delay in microseconds.

    But the interface delay command wants the value in "tens of microseconds", one 0 has to go before entering the command.

  • I did the metric weights in the previous lab. With this one I changed the bandwidth to match the task, and left the default metric weights; I want to be able to account for any requirements in a tasks that doesn't allow me to change metric weights. Then I did an offset list on R1 to change inbound from R3. I made the metric exactly 4000000. Then I did another offset list to increase the metric from R2 to R1, to have 5:1 ratio (20000000)

    R2
    interface serial 0/0.12
    bandwidth 256
    interface serial 0/0.13
    bandwidth 1280

    R3
    interface serial 1/0.23
    bandwidth 1280
    interface serial 1/2
    bandwidth 1536

    R1
    interface serial 0/1
    bandwidth 1536
    interface serial 0/0
    bandwidth 256

    access-list 1 permit 164.1.26.0 0.0.0.255
    router eigrp 100
    offset-list 1 in 950528 Serial0/1 !(This made the metric exactly 4000000 in R1s routing table)
    offset-list 1 in 9744128 Serial0/0 !(This made the metric exactly 20000000 in R1s routing table)

    Now I had my target delay of 390630

    The problem with this is that it changes the neighbors reported delay. No biggie, My R2 router has an FA interface with a delay of 1000. I took the total delay that was reported with the offset list, subtracted 1000, then divided by 10 and put that on the serial interface towards R2. And finally removed the offset list inbound from R2.

    (390630 - 1000)/10 = 38963

    R1
    interface serial 0/0
    delay 38963

    router eigrp 100
    no offset-list 1 in 9744128 Serial0/0

    Routing entry for 164.1.26.0/24
      Known via "eigrp 100", distance 90, metric 4000000, type internal
      Redistributing via eigrp 100
      Last update from 164.1.12.2 on Serial0/0, 00:00:13 ago
      Routing Descriptor Blocks:
      * 164.1.13.3, from 164.1.13.3, 00:00:13 ago, via Serial0/1
          Route metric is 4000000, traffic share count is 5
          Total delay is 78130 microseconds, minimum bandwidth is 1280 Kbit
          Reliability 255/255, minimum MTU 1500 bytes
          Loading 1/255, Hops 2
        164.1.12.2, from 164.1.12.2, 00:00:13 ago, via Serial0/0
          Route metric is 20000000, traffic share count is 1
          Total delay is 390630 microseconds, minimum bandwidth is 256 Kbit
          Reliability 255/255, minimum MTU 1500 bytes
          Loading 1/255, Hops 1

    IP-EIGRP (AS 100): Topology entry for 164.1.26.0/24
      State is Passive, Query origin flag is 1, 1 Successor(s), FD is 4000000
      Routing Descriptor Blocks:
      164.1.13.3 (Serial0/1), from 164.1.13.3, Send flag is 0x0
          Composite metric is (4000000/3488000), Route is Internal
          Vector metric:
            Minimum bandwidth is 1280 Kbit
            Total delay is 78130 microseconds
            Reliability is 255/255
            Load is 1/255
            Minimum MTU is 1500
            Hop count is 2
      164.1.12.2 (Serial0/0), from 164.1.12.2, Send flag is 0x0
          Composite metric is (20000000/281600), Route is Internal
          Vector metric:
            Minimum bandwidth is 256 Kbit
            Total delay is 390630 microseconds
            Reliability is 255/255
            Load is 1/255
            Minimum MTU is 1500
            Hop count is 1

    The whole process took me about 3 minutes to do, but about 30 minutes to think of a way to make it quick and easy for future tasks that require this.

  • I think the better/faster solution is not to fiddle with the delay at all. You can just set 'metric weights 0 1 0 0 0 0' and now you just rely on the bandwidth. The bandwidth is already at a ratio of 5:1 (1280k:256k). The variance will have to be set to 6 tho...

    But it's a good task on metric tweaking.

    This is what I did. Seemed to work fine. Knowing to change the variance to 6 was the easy part. When messing with load sharing I up the variance to like 80, so I know if I'm just off on my metrics.

  • Rack1R1#show ip route 164.1.26.0
    Routing entry for 164.1.26.0/24
      Known via "eigrp 100", distance 90, metric 2002944, type internal
      Redistributing via eigrp 100
      Last update from 164.1.12.2 on Serial0/0/0, 00:49:08 ago
      Routing Descriptor Blocks:
      * 164.1.13.3, from 164.1.13.3, 00:49:08 ago, via Serial0/1/0
          Route metric is 2002944, traffic share count is 5
          Total delay is 120 microseconds, minimum bandwidth is 1280 Kbit
          Reliability 255/255, minimum MTU 1500 bytes
          Loading 1/255, Hops 2
        164.1.12.2, from 164.1.12.2, 00:49:08 ago, via Serial0/0/0
          Route metric is 10002944, traffic share count is 1
          Total delay is 120 microseconds, minimum bandwidth is 256 Kbit
          Reliability 255/255, minimum MTU 1500 bytes
          Loading 1/255, Hops 1

     

    Rack1R1#show run int s0/0/0
    Building configuration...

    Current configuration : 190 bytes
    !
    interface Serial0/0/0
     bandwidth 256
     ip address 164.1.12.1 255.255.255.0
     encapsulation frame-relay
     delay 2
     frame-relay map ip 164.1.12.2 102 broadcast
     no frame-relay inverse-arp
    end

    Rack1R1#show run int s0/1/0
    Building configuration...

    Current configuration : 94 bytes
    !
    interface Serial0/1/0
     ip address 164.1.13.1 255.255.255.0
     encapsulation ppp
     delay 1
    end

    Rack1R3#show run int s1/1.23
    Building configuration...

    Current configuration : 165 bytes
    !
    interface Serial1/1.23 point-to-point
     bandwidth 1280
     ip address 164.1.23.3 255.255.255.0
     delay 1
     snmp trap link-status
     frame-relay interface-dlci 312  
    end

    router eigrp 100
     variance 5
     network 150.1.1.1 0.0.0.0
     network 164.1.12.1 0.0.0.0
     network 164.1.13.1 0.0.0.0
     network 164.1.18.1 0.0.0.0
     no auto-summary
     eigrp router-id 150.1.1.1

    Since bandwidth already has a ratio 5:1 would'n it be a better solution?

     

     

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