[c-nsp] multipath BGP not balancing equally.

[bas]

Hi,

I have an issue with unequal multipath BGP loadbalancing
It is a 6500 / SUP720-3BXL running 12.2.18SXF16

There are four eBGP sessions to a transit carriers ASN, all with full table

However one out of four interfaces sends about 2Gbps less than the other three.

RTR-HV7#sh int ten 2/2 | i output rate
  1 minute output rate 6357052000 bits/sec, 546295 packets/sec
RTR-HV7#sh int ten 3/1 | i output rate
  1 minute output rate 8509719000 bits/sec, 729490 packets/sec
RTR-HV7#sh int ten 3/3 | i output rate
  1 minute output rate 8721235000 bits/sec, 746980 packets/sec
RTR-HV7#sh int ten 4/4 | i output rate
  1 minute output rate 8592400000 bits/sec, 734864 packets/sec

All four sessions have the same settings (in the same peer-group)
Through netflow I've tried to deduct if there are specific ASN's not
chosen through the nexthop that has less traffic, but that does not
seem to be the case.

I've looked at "ip cef load-sharing algorithm universal" however that
seems to already be the default algorithm in current IOS versions.

With any prefix I test through "sh ip cef x.x.x.x detail" it seems all
four paths are used.

Thanks in advance,

Bas