Solved: Re: EIGRP Variance Issue

sivam siva · ‎03-30-2019

Hello all

Can anyone help to understand below error ?

""R3(config-router)#var 128
R3(config-router)#
*Mar 30 20:40:52.723: %COMMON_FIB-4-UNEQUAL: Ratio of unequal path weightings (1 60) prevents oce IP adj out of Serial6/0 from being used. ""

Please refer below outputs if required

R3#sh run
Building configuration...

Current configuration : 2488 bytes
!
! Last configuration change at 20:09:52 UTC Sat Mar 30 2019
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname R3
!
boot-start-marker
boot-end-marker
!
!
logging console informational
logging monitor informational
!
no aaa new-model
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
!
!
no ip domain lookup
no ipv6 cef
!
!
multilink bundle-name authenticated
!
!
archive
log config
hidekeys
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 3.3.3.3 255.255.255.255
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface GigabitEthernet1/0
no ip address
shutdown
negotiation auto
!
interface GigabitEthernet2/0
ip address 40.0.0.10 255.255.255.252
ip summary-address eigrp 100 20.0.0.0 255.0.0.0
ip summary-address eigrp 100 30.0.0.0 255.0.0.0
ip summary-address eigrp 100 40.0.0.0 255.0.0.0
ip summary-address eigrp 100 50.0.0.0 255.0.0.0
negotiation auto
!
interface GigabitEthernet3/0
mtu 1501
ip address 40.0.0.2 255.255.255.252
delay 20
negotiation auto
!
interface GigabitEthernet4/0
no ip address
shutdown
negotiation auto
!
interface GigabitEthernet5/0
no ip address
shutdown
negotiation auto
!
interface Serial6/0
ip address 40.0.0.5 255.255.255.252
serial restart-delay 0
!
interface Serial6/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial6/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial6/3
no ip address
shutdown
serial restart-delay 0
!
interface Serial6/4
no ip address
shutdown
serial restart-delay 0
!
interface Serial6/5
no ip address
shutdown
serial restart-delay 0
!
interface Serial6/6
no ip address
shutdown
serial restart-delay 0
!
interface Serial6/7
no ip address
shutdown
serial restart-delay 0
!
!
router eigrp 100
distribute-list route-map leftblock in Serial6/0
variance 128
network 3.3.3.3 0.0.0.0
network 40.0.0.0 0.0.0.3
network 40.0.0.4 0.0.0.3
network 40.0.0.8 0.0.0.3
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
!
!
ip prefix-list leftblock seq 20 permit 10.0.0.0/14 ge 16
logging alarm informational
!
route-map leftblock deny 20
match ip address prefix-list leftblock
!
route-map leftblock permit 99
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous

R3#
R3#
R3#
R3#sh ip eigrp topology
EIGRP-IPv4 Topology Table for AS(100)/ID(3.3.3.3)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status

P 20.0.0.16/30, 2 successors, FD is 33536
via 40.0.0.1 (33536/28416), GigabitEthernet3/0
via 40.0.0.6 (2173184/28928), Serial6/0
P 22.2.2.2/32, 1 successors, FD is 130816
via 40.0.0.9 (130816/128256), GigabitEthernet2/0
P 40.0.0.8/30, 1 successors, FD is 2816
via Connected, GigabitEthernet2/0
P 30.0.0.16/30, 1 successors, FD is 8192
via 40.0.0.1 (8192/3072), GigabitEthernet3/0
P 40.0.0.4/30, 1 successors, FD is 2169856
via Connected, Serial6/0
P 7.7.7.7/32, 1 successors, FD is 2298112
via 40.0.0.6 (2298112/130816), Serial6/0
P 20.0.0.8/30, 2 successors, FD is 2175232
via 40.0.0.1 (2175232/2170112), GigabitEthernet3/0
via 40.0.0.6 (2682368/2170368), Serial6/0
P 100.100.100.100/32, 2 successors, FD is 136192
via 40.0.0.6 (2298112/130816), Serial6/0
via 40.0.0.1 (136192/131072), GigabitEthernet3/0
P 4.4.4.4/32, 2 successors, FD is 2814976
via 40.0.0.1 (2814976/2809856), GigabitEthernet3/0
via 40.0.0.6 (3322112/2810112), Serial6/0
P 30.0.0.4/30, 1 successors, FD is 33280
via 40.0.0.1 (33280/28160), GigabitEthernet3/0
P 10.1.0.0/16, 1 successors, FD is 3072
via 40.0.0.9 (3072/2816), GigabitEthernet2/0
P 10.0.0.0/16, 1 successors, FD is 3072
via 40.0.0.9 (3072/2816), GigabitEthernet2/0
P 5.5.5.5/32, 2 successors, FD is 135936
via 40.0.0.1 (135936/130816), GigabitEthernet3/0
via 40.0.0.6 (2298112/130816), Serial6/0
P 50.0.0.0/8, 1 successors, FD is 8192
via Summary (8192/0), Null0
P 50.0.0.0/30, 1 successors, FD is 8192
via 40.0.0.1 (8192/3072), GigabitEthernet3/0
via 40.0.0.6 (2170368/3072), Serial6/0
P 40.0.0.12/30, 1 successors, FD is 8448
via 40.0.0.1 (8448/3328), GigabitEthernet3/0
via 40.0.0.6 (2170112/2816), Serial6/0
P 30.0.0.0/8, 1 successors, FD is 3328
via Summary (7936/0), Null0
via 40.0.0.6 (2170112/2816), Serial6/0
P 30.0.0.0/30, 1 successors, FD is 7936
via 40.0.0.1 (7936/2816), GigabitEthernet3/0
P 10.2.0.0/24, 1 successors, FD is 8448
via 40.0.0.1 (8448/3328), GigabitEthernet3/0
P 2.2.2.2/32, 2 successors, FD is 135680
via 40.0.0.1 (135680/128256), GigabitEthernet3/0
via 40.0.0.6 (2298368/131072), Serial6/0
P 30.0.0.8/29, 2 successors, FD is 3328
via 40.0.0.1 (7936/2816), GigabitEthernet3/0
via 40.0.0.9 (3328/3072), GigabitEthernet2/0
P 10.3.0.0/24, 1 successors, FD is 33792
via 40.0.0.1 (33792/28672), GigabitEthernet3/0
P 20.0.0.20/30, 1 successors, FD is 28416
via 40.0.0.9 (28416/28160), GigabitEthernet2/0
P 6.6.6.6/32, 2 successors, FD is 136192
via 40.0.0.6 (2297856/128256), Serial6/0
via 40.0.0.1 (136192/131072), GigabitEthernet3/0
P 40.0.0.0/8, 1 successors, FD is 2816
via Summary (2816/0), Null0
P 40.0.0.0/30, 1 successors, FD is 7680
via Connected, GigabitEthernet3/0
via 40.0.0.6 (2170624/3328), Serial6/0
P 1.0.0.0/8, 2 successors, FD is 2174976
via 40.0.0.1 (2174976/2169856), GigabitEthernet3/0
via 40.0.0.6 (2682368/2170368), Serial6/0
P 3.3.3.3/32, 1 successors, FD is 128256
via Connected, Loopback0
P 20.0.0.0/29, 2 successors, FD is 2175232
via 40.0.0.1 (2175232/2170112), GigabitEthernet3/0
via 40.0.0.6 (2682112/2170112), Serial6/0
P 20.0.0.0/8, 1 successors, FD is 28416
via Summary (28416/0), Null0
P 50.0.0.4/30, 2 successors, FD is 2175488
via 40.0.0.6 (2682112/2170112), Serial6/0
via 40.0.0.1 (2175488/2170368), GigabitEthernet3/0

R3#
R3#
R3#
R3#
R3#
R3#
R3#
R3#
R3#
R3#
R3#sh ip eigrp topology all
EIGRP-IPv4 Topology Table for AS(100)/ID(3.3.3.3)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status

P 20.0.0.16/30, 2 successors, FD is 33536, serno 71
via 40.0.0.1 (33536/28416), GigabitEthernet3/0
via 40.0.0.6 (2173184/28928), Serial6/0
P 22.2.2.2/32, 1 successors, FD is 130816, serno 39
via 40.0.0.9 (130816/128256), GigabitEthernet2/0
via 40.0.0.6 (2298624/131328), Serial6/0
via 40.0.0.1 (135936/130816), GigabitEthernet3/0
P 40.0.0.8/30, 1 successors, FD is 2816, serno 5
via Connected, GigabitEthernet2/0
P 30.0.0.16/30, 1 successors, FD is 8192, serno 14
via 40.0.0.1 (8192/3072), GigabitEthernet3/0
P 40.0.0.4/30, 1 successors, FD is 2169856, serno 24
via Connected, Serial6/0
P 7.7.7.7/32, 1 successors, FD is 2298112, serno 43
via 40.0.0.6 (2298112/130816), Serial6/0
P 20.0.0.8/30, 2 successors, FD is 2175232, serno 66
via 40.0.0.1 (2175232/2170112), GigabitEthernet3/0
via 40.0.0.6 (2682368/2170368), Serial6/0
P 100.100.100.100/32, 2 successors, FD is 136192, serno 72
via 40.0.0.6 (2298112/130816), Serial6/0
via 40.0.0.1 (136192/131072), GigabitEthernet3/0
P 4.4.4.4/32, 2 successors, FD is 2814976, serno 67
via 40.0.0.1 (2814976/2809856), GigabitEthernet3/0
via 40.0.0.6 (3322112/2810112), Serial6/0
P 30.0.0.4/30, 1 successors, FD is 33280, serno 10
via 40.0.0.1 (33280/28160), GigabitEthernet3/0
P 10.1.0.0/16, 1 successors, FD is 3072, serno 37
via 40.0.0.9 (3072/2816), GigabitEthernet2/0
via 40.0.0.1 (8192/3072), GigabitEthernet3/0
P 10.0.0.0/16, 1 successors, FD is 3072, serno 36
via 40.0.0.9 (3072/2816), GigabitEthernet2/0
via 40.0.0.1 (8192/3072), GigabitEthernet3/0
P 5.5.5.5/32, 2 successors, FD is 135936, serno 73
via 40.0.0.1 (135936/130816), GigabitEthernet3/0
via 40.0.0.6 (2298112/130816), Serial6/0
P 50.0.0.0/8, 1 successors, FD is 8192, serno 18
via Summary (8192/0), Null0
P 50.0.0.0/30, 1 successors, FD is 8192, serno 15
via 40.0.0.1 (8192/3072), GigabitEthernet3/0
via 40.0.0.6 (2170368/3072), Serial6/0
P 40.0.0.12/30, 1 successors, FD is 8448, serno 48
via 40.0.0.1 (8448/3328), GigabitEthernet3/0
via 40.0.0.6 (2170112/2816), Serial6/0
P 30.0.0.0/8, 1 successors, FD is 3328, serno 77
via Summary (7936/0), Null0
via 40.0.0.6 (2170112/2816), Serial6/0
P 30.0.0.0/30, 1 successors, FD is 7936, serno 9
via 40.0.0.1 (7936/2816), GigabitEthernet3/0
P 10.2.0.0/24, 1 successors, FD is 8448, serno 46
via 40.0.0.1 (8448/3328), GigabitEthernet3/0
P 2.2.2.2/32, 2 successors, FD is 135680, serno 74
via 40.0.0.1 (135680/128256), GigabitEthernet3/0
via 40.0.0.6 (2298368/131072), Serial6/0
P 30.0.0.8/29, 2 successors, FD is 3328, serno 75
via 40.0.0.1 (7936/2816), GigabitEthernet3/0
via 40.0.0.9 (3328/3072), GigabitEthernet2/0
P 10.3.0.0/24, 1 successors, FD is 33792, serno 47
via 40.0.0.1 (33792/28672), GigabitEthernet3/0
P 20.0.0.20/30, 1 successors, FD is 28416, serno 38
via 40.0.0.9 (28416/28160), GigabitEthernet2/0
via 40.0.0.6 (2173184/28928), Serial6/0
via 40.0.0.1 (33536/28416), GigabitEthernet3/0
P 6.6.6.6/32, 2 successors, FD is 136192, serno 76
via 40.0.0.6 (2297856/128256), Serial6/0
via 40.0.0.1 (136192/131072), GigabitEthernet3/0
P 40.0.0.0/8, 1 successors, FD is 2816, serno 6
via Summary (2816/0), Null0
P 40.0.0.0/30, 1 successors, FD is 7680, serno 2
via Connected, GigabitEthernet3/0
via 40.0.0.6 (2170624/3328), Serial6/0
P 1.0.0.0/8, 2 successors, FD is 2174976, serno 68
via 40.0.0.1 (2174976/2169856), GigabitEthernet3/0
via 40.0.0.6 (2682368/2170368), Serial6/0
P 3.3.3.3/32, 1 successors, FD is 128256, serno 1
via Connected, Loopback0
P 20.0.0.0/29, 2 successors, FD is 2175232, serno 69
via 40.0.0.1 (2175232/2170112), GigabitEthernet3/0
via 40.0.0.6 (2682112/2170112), Serial6/0
P 20.0.0.0/8, 1 successors, FD is 28416, serno 41
via Summary (28416/0), Null0
P 50.0.0.4/30, 2 successors, FD is 2175488, serno 70
via 40.0.0.6 (2682112/2170112), Serial6/0
via 40.0.0.1 (2175488/2170368), GigabitEthernet3/0

R3#
R3#sh ip protocols
*** IP Routing is NSF aware ***

Routing Protocol is "eigrp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Serial6/0 filtered by (per-user), default is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(100)
Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
NSF-aware route hold timer is 240
Router-ID: 3.3.3.3
Topology : 0 (base)
Active Timer: 3 min
Distance: internal 90 external 170
Maximum path: 4
Maximum hopcount 100
Maximum metric variance 128

Automatic Summarization: disabled
Address Summarization:
50.0.0.0/8 for Gi2/0
Summarizing 2 components with metric 8192
40.0.0.0/8 for Gi2/0
Summarizing 4 components with metric 2816
30.0.0.0/8 for Gi2/0
Summarizing 4 components with metric 7936
20.0.0.0/8 for Gi2/0
Summarizing 4 components with metric 28416
Maximum path: 4
Routing for Networks:
3.3.3.3/32
40.0.0.0/30
40.0.0.4/30
40.0.0.8/30
Routing Information Sources:
Gateway Distance Last Update
40.0.0.9 90 00:23:58
40.0.0.1 90 00:23:58
40.0.0.6 90 00:23:58
Distance: internal 90 external 170

R3#sh ip route eigrp 100
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override

Gateway of last resort is not set

D 1.0.0.0/8 [90/2682368] via 40.0.0.6, 00:24:57, Serial6/0
[90/2174976] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
2.0.0.0/32 is subnetted, 1 subnets
D 2.2.2.2 [90/2298368] via 40.0.0.6, 00:24:57, Serial6/0
[90/135680] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
4.0.0.0/32 is subnetted, 1 subnets
D 4.4.4.4 [90/3322112] via 40.0.0.6, 00:24:57, Serial6/0
[90/2814976] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
5.0.0.0/32 is subnetted, 1 subnets
D 5.5.5.5 [90/2298112] via 40.0.0.6, 00:24:57, Serial6/0
[90/135936] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
6.0.0.0/32 is subnetted, 1 subnets
D EX 6.6.6.6 [170/2297856] via 40.0.0.6, 00:24:57, Serial6/0
[170/136192] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
7.0.0.0/32 is subnetted, 1 subnets
D EX 7.7.7.7 [170/2298112] via 40.0.0.6, 00:24:57, Serial6/0
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
D 10.0.0.0/16 [90/3072] via 40.0.0.9, 00:24:57, GigabitEthernet2/0
D 10.1.0.0/16 [90/3072] via 40.0.0.9, 00:24:57, GigabitEthernet2/0
D 10.2.0.0/24 [90/8448] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 10.3.0.0/24 [90/33792] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
20.0.0.0/8 is variably subnetted, 5 subnets, 3 masks
D 20.0.0.0/8 is a summary, 00:24:57, Null0
D 20.0.0.0/29 [90/2682112] via 40.0.0.6, 00:24:57, Serial6/0
[90/2175232] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 20.0.0.8/30 [90/2682368] via 40.0.0.6, 00:24:57, Serial6/0
[90/2175232] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 20.0.0.16/30 [90/2173184] via 40.0.0.6, 00:24:57, Serial6/0
[90/33536] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 20.0.0.20/30 [90/28416] via 40.0.0.9, 00:24:57, GigabitEthernet2/0
22.0.0.0/32 is subnetted, 1 subnets
D 22.2.2.2 [90/130816] via 40.0.0.9, 00:24:57, GigabitEthernet2/0
30.0.0.0/8 is variably subnetted, 5 subnets, 3 masks
D 30.0.0.0/8 is a summary, 00:24:57, Null0
D 30.0.0.0/30 [90/7936] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 30.0.0.4/30 [90/33280] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 30.0.0.8/29 [90/3328] via 40.0.0.9, 00:24:57, GigabitEthernet2/0
[90/7936] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 30.0.0.16/30 [90/8192] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
40.0.0.0/8 is variably subnetted, 8 subnets, 3 masks
D 40.0.0.0/8 is a summary, 00:24:57, Null0
D 40.0.0.12/30 [90/8448] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
50.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
D 50.0.0.0/8 is a summary, 00:24:57, Null0
D 50.0.0.0/30 [90/8192] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
D 50.0.0.4/30 [90/2682112] via 40.0.0.6, 00:24:57, Serial6/0
[90/2175488] via 40.0.0.1, 00:24:57, GigabitEthernet3/0
100.0.0.0/32 is subnetted, 1 subnets
D 100.100.100.100 [90/2298112] via 40.0.0.6, 00:24:57, Serial6/0
[90/136192] via 40.0.0.1, 00:24:57, GigabitEthernet3/0

Kevin Rivest · ‎03-31-2019

In response to your question. This is what the command is doing:

When you configure the command traffic-share min across-interfaces you are telling the router to distribute traffic across all paths equally even though the paths have unequal metrics.

Why does does this fix the issue?

The error you are getting is a software issue or bug. The error is saying that it cannot install a path in the FIB with an unequal cost weighting of 1 to 60, such as (looks like its the closest):

P 20.0.0.16/30, 2 successors, FD is 33536, serno 71
via 40.0.0.1 (33536/28416), GigabitEthernet3/0
via 40.0.0.6 (2173184/28928), Serial6/0

That means that the FIB is pointing to the adjacency table unequally in a ratio of 1 entry for Serial6/0 for every 60 entries for GigabitEthernet3/0 in order to achieve unequal cost load balancing in CEF.

The issue is that due to a software issue the FIB cannot install the pointers to the adjacency table in that ratio (1 60).

The reason the traffic-share min across-interfaces command fixes this is you are basically falling back to equal cost load balancing or (1 1) when it comes to CEF. For every one pointer in the FIB to Serial6/0 in the adjacency table there is one pointer in the FIB to GigabitEthernet3/0 in the adjacency table. So you are not running into the software error of installing a (1 60) traffic weighting in the FIB.

Hope that answers your questions.

View solution in original post

Deepak Kumar · ‎03-30-2019

Hi,

Try with a command:

router eigrp 100
distribute-list route-map leftblock in Serial6/0
variance 128
network 3.3.3.3 0.0.0.0
network 40.0.0.0 0.0.0.3
network 40.0.0.4 0.0.0.3
network 40.0.0.8 0.0.0.3
traffic-share min across-interfaces

Regards,
Deepak Kumar

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

networkcheff · ‎03-30-2019

Hi ,

Variance is just the multiplier, it seems you are using a very high number, try using 2 or 3 and check if that works.

If you found my answer to be useful please do not hesitate click on the Star button and answered.

sivam siva · ‎03-30-2019

@networkcheff

Thanks for the reply

I can understand the concept and use of variance and but why router prompts error if i configure max variance ?

I did just for testing , fortunately i came to know there is something to learn.

thanks in advance.

Deepak Kumar · ‎03-31-2019

Hi,

The EIGRP will do unequal-cost load balancing if configured with the variance command. Use the variance n command in order to instruct the router to include routes with a metric of less than n times the minimum metric route for that destination. The variable n can take a value between 1 and 128. The default is 1, which means equal cost load balancing. Traffic is also distributed among the links with unequal costs, proportionately, with respect to the metric.

Note: If a path is not a feasible successor, the path is not used in load balancing

Regards,

Deepak Kumar

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

sivam siva · ‎03-30-2019

@Deepak Kumar

Thanks for the reply

Now I didn't get that error, after applied the command which you told.

could you tell why router is not throwing that error now and what is the meaning of that error ?

Thanks in advance.

networkcheff · ‎03-30-2019

Ohh thats cool, I know that command

With the traffic-share command, if there are multiple minimum-cost paths and traffic-share-min is configured, EIGRP will use equal-cost load balancing. By default, the command is set to balanced, where traffic will be distributed proportionally to the ratio of the metrics. For example, if variance is set to 3 and traffic-share is set to balanced, the best route will transport traffic three times that of the worst route.

For a route to be included in unequal-cost load sharing, three other conditions must be met:

The maximum-paths limit must not be exceeded as a result of adding this route to the load-sharing group.
The downstream router must be metrically closer to the destination.
The metric of the lowest-cost route, multiplied by the variance, must be greater than the metric of the route to be added to the load-sharing group.