WITH VARIANCE or WITHOUT VARIANCE

[alsayed]

Hello!

i have 2 wirless(1000M;100M) Link Connected to the HO.The routing protocol is EIGRP.if i advertised the 2 network like this.

router EIGRP 100

NETWORK 192.168.1.0 0.0.0.255

NETWORK 10.10.1.0 0.0.0.255

okay.Now what is happen if i don't include the VARIANCE Command,in my situation will be

:

VARIANCE 2

10XS FOR UR HELP

[farkascsgy]

Variance is used for load balancing over unequal metric lines. So if you have multiple paths to the destination in default there is only load balance if the metric of the paths are same, with the variance command you can do load balance over unequal metric lines.

Variance is totally independent the number of network command under the eigrp process. So if you don't want to do unequal load balancig you don't need use variance command.

You can check that how many FS in the eigrp process (show ip eigrp topology all-links) and if more than one and you would like to do load balancig over these paths, in that case use vaiance.

If you have two wireless uplink and you don't use variance 2 command your uplink will be only the better (1000M) and the other is only FS.

Bye

FCS

Please rate me if I helped.

[alsayed]

Hi Friend!

did u mean in this"Variance is used for load balancing over unequal metric lines" my 2 wirless link(100M;1000M)IN My Situation what u advise me to use variance or what.

10xs

[farkascsgy]

Hello,

In your situation I don't think so that you need load balance, if your link is 1000M and 100M you can use the first as successor (primary) and the 100M lines as feasible succesor (backup). In case of failure when your 1000M line is down Eigrp converges very fast and use the 100M line as primary - probably you don't feel that there was a change in the route (just from logs :) ).

In my opinion you don't need use load balancing (one line is enough).

Bye

FCS

Rate me if I helped.

[alsayed]

HI Friend.

Thank U.

[devang_etcom]

hi ali,

here you can get exact idea of the variance command...

consider two router connected with the three link...

routerA ----link with metrics 5----routerB

routerA ----link with metrics 9---routerB

routerA ----link with metrics 14---routerB

normaly routing protocol install the path with the best metrics in rotuting table...in our case link with metrics 5 will be in routing table...

variance 2:

but now you want to go for the loadbalancing then you are using variance command... and by using variance command you are allowing the other path to the destination into your routing table...in our case when you enter the variance 2 command then first and second link will be added into the routing table as this calculation is based on the lowest metrics link... and varianc number is multiplied to the lower number metics so in our case varianc is 2 and lowest metrics is 5 therfore 2X5=10 ... as per this calculation paths which are equal to or less than(depends on protocol IGRP & EIGRP) 10 will appeare in to the routing table...

variance3:

now take variance as 3 then you will have this calculation like 3X5=15... in your routing table all the pathe which are less than or equal to the 15 will appeare in to the routing table so here you will have all the three path of metircs 5,9 and 14 will be available in to the routing table when you use the variance 3 command... and now unequl cost path load balancing will take place in your network...

hope this will help you

rate this post if it helps...

regards

Devang