Requirements:
- Configure unequal cost load balancing so that traffic from R6 going to VLAN 9 is load balanced between R1 and SW1.
- The traffic share should be configured in such a way that the link to SW1 is used five times as much as the link to R1.
- Verify this by configuring per-packet load balancing on R6.
pls take note that all routers are using delay only; "metric weights 0 0 0 1 0 0"
PATH R6>SW1>SW3
Rack1R6#sho int fa0/0.67 | include DLY
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
Rack1SW1#sho int vlan79 | include DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Rack1SW3#sho int vlan9 | inc DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Total delay of 120 microseconds
Metric = 256 * (120/10) = 3072
Rack1R6#sho ip eigrp topology 155.1.9.0 255.255.255.0
IP-EIGRP (AS 100): Topology entry for 155.1.9.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3072
Routing Descriptor Blocks:
155.1.67.7 (FastEthernet0/0.67), from 155.1.67.7, Send flag is 0x0
Composite metric is (3072/512), Route is Internal
Vector metric:
Minimum bandwidth is 100000 Kbit
Total delay is 120 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
PATH R6>R1>R3>SW1>SW3
Rack1R6#sho int fa0/0.146 | include DLY
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
Rack1R1#sho int s0/1 | inc DLY
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
Rack1R3#sho int fa0/0 | inc DLY
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
Rack1SW1#sho int vlan79 | include DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Rack1SW3#sho int vlan9 | inc DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Total delay of 20,220 microseconds
Metric = 256 * (20,220/10) = 517632
so the successor route is via SW1.
note:
FEASIBILITY CONDITION:
IF THE ADVERTISED DISTANCE OF AN ALTERNATIVE ROUTE IS LOWER THAN THE FEASIBLE DISTANCE OF THE SUCCESSOR, THE ROUTE IS A LOOP FREE PATH AND CAN BE CONSIDEED FOR LOAD BALANCING.
ADVERTISED DISTANCE OF R1
Rack1R1#sho int s0/1 | inc DLY
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
Rack1R3#sho int fa0/0 | inc DLY
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
Rack1SW1#sho int vlan79 | include DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Rack1SW3#sho int vlan9 | inc DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Total delay of 20,120 microseconds
Metric = 256 * (20,120/10) = 515072 - CANT BE CONSIDERED A FEASIBLE SUCCESSOR.
ADJUSTING THE DELAY ALONG PATH R6>R1>R3>SW1>SW3
R1- 10 usec
R3- 10 usec
Rack1R1(config)#interface Serial0/1
Rack1R1(config-if)#delay 1
Rack1R3(config)#interface FastEthernet0/0
Rack1R3(config-if)#delay 1
Rack1R6#sho int fa0/0.146 | include DLY
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
Rack1R1#sho int s0/1 | inc DLY
MTU 1500 bytes, BW 1544 Kbit, DLY 10 usec,
Rack1R3#sho int fa0/0 | inc DLY
MTU 1500 bytes, BW 100000 Kbit, DLY 10 usec,
Rack1SW1#sho int vlan79 | include DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Rack1SW3#sho int vlan9 | inc DLY
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
Total delay of 140 microseconds
Metric = 256 * (140/10) = 3584 since this still higher than 3072 so the path is not the successor.
howerver the new metric Advertised by R1 = 256* 40/10 microseconds = 1024 this route is now a feasible successor.
Rack1R6#sho ip eigrp topology 155.1.9.0 255.255.255.0
IP-EIGRP (AS 100): Topology entry for 155.1.9.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3072
Routing Descriptor Blocks:
155.1.67.7 (FastEthernet0/0.67), from 155.1.67.7, Send flag is 0x0
Composite metric is (3072/512), Route is Internal
Vector metric:
Minimum bandwidth is 100000 Kbit
Total delay is 120 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
155.1.146.1 (FastEthernet0/0.146), from 155.1.146.1, Send flag is 0x0
Composite metric is (3584/1024), Route is Internal
Vector metric:
Minimum bandwidth is 1544 Kbit
Total delay is 140 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 4
VARIANCE COMMAND: the actual variance value is arbitrary as long as the FD, 3072, times the variance is greater than the total composite metric through R1.
Rack1R6(config)#router eigrp 100
Rack1R6(config-router)#variance 128
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, 00:00:28 ago
Routing Descriptor Blocks:
155.1.146.1, from 155.1.146.1, 00:00:28 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, 00:00:28 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
now the traffic share is 103:120. to achieve the desired 1:5
the values that can be used on R1, R3 and R6 for the delay can have a multiple valid options; as long 2 conditions are true;
1. advertised distance of R1 sends to R6 must be lower than R6's Feasible Distance.
2. entire composite result R6 calculates through R1 should be five times the feasible distance.
IN THIS CASE R1'S ADVERTISED IS 40 microseconds or 4 tens of microseconds.
3072 * 5 = (R6 to R1 DLY + 4) * 256
R6 to R1 SHOULD BE 56
Rack1R6(config)#int fa0/0.146
Rack1R6(config-subif)#delay 56
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, 00:00:07 ago
Routing Descriptor Blocks:
155.1.146.1, from 155.1.146.1, 00:00:07 ago, via FastEthernet0/0.146
Route metric is 15360, traffic share count is 1
Total delay is 600 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, 00:00:07 ago, via FastEthernet0/0.67
Route metric is 3072, traffic share count is 5
Total delay is 120 microseconds, minimum bandwidth is 100000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 2
VERIFICATION:
Rack1R6(config)#interface FastEthernet0/0.67
Rack1R6(config-subif)#no ip route-cache
Rack1R6(config-subif)#ip load-sharing per-packet
Rack1R6(config-subif)#interface FastEthernet0/0.146
Rack1R6(config-subif)#no ip route-cache
Rack1R6(config-subif)#ip load-sharing per-packet
Rack1R1#config t
Enter configuration commands, one per line. End with CNTL/Z.
Rack1R1(config)#access-list 100 permit icmp any host 155.1.9.9 log
Rack1R1(config)#access-list 100 permit ip any any
Rack1R1(config)#interface FastEthernet0/0
Rack1R1(config-if)#ip access-group 100 in
Rack1SW1#config t
Enter configuration commands, one per line. End with CNTL/Z.
Rack1SW1(config)#access-list 100 permit icmp any host 155.1.9.9 log
Rack1SW1(config)#access-list 100 permit ip any any
Rack1SW1(config)#interface Vlan67
Rack1SW1(config-if)#ip access-group 100 in
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