CEF polarization ?
in my working place i was facing loadbalancing issues,
this is what happened 2 ASR9K'S having 4 10 gig interface between
them,no cost modification was done,routers running ospf and isis
as igp,the issues was traffic was flowing HEAVILY through
one of the issues,we raised a TAC-case and engineer issued
ip cef loadbalancing algorithm adjust <value>
and he said it may be cause of uneven flows of carying bandwidth
and he tuned the value to 9 and after some hours the utilization
got slightly better .
i understand CEF works like this,
for a single source-destination ip pair the algorithm
will xor the bits of source and destination pair and chooses
the link to be used,we are using the default method of
per destination based load-sharing.
after encountered this issue,i was told by TAC engineer
that it was cef polarization problem,
i tried to undertand the methods to overcome this problem
they said we can use ports and some other blogs suggested
to use universal id algorithm
my question is
1)can any one explain with a example to understand
how we can avoid cef polarization in our network ?
some help would be appreciated...