In TELIPS network, an AR46-80 router has been cutover to NE40-4 router. This router is in Faisalabad city and connects to Lahore city NE40-8 router using 2 mpgroups of 8 E1's each. After cutover the graph in MRTG (a linux based network tool to analyse network traffic ) shows that the traffic is not balanced on both mpgroups.
The OSPF cost is checked and found no problem in configuration. The version for NE40-4 and NE40-8 is same which was also checked and found OK.
In TELIPS network the AR46-80 router is cutover to NE40-4 router. In AR46-80, the default load balacing criterion is per packet so we do not have to configure anything extra for the OSPF load balancing and just after making virtual-template and ospf configuration it works normal. But in NE40-4, the default lolad balancing criterion is per stream, so we have to change it to per packet to get the load balancing in OSPF.
I use command "hash-context next-hop packet udp" under system view and the problem was solved.
After making configuration, MRTG and interface statistics are observed and found OK.
Load balancing have two types of work mode, one is working base on traffic, another one is working base on packet. NE40 router default work mode is base on traffic. if we want that both router's mpgroups have same amount of packets then we can chang its working mode base on packet by using command "hash-context next-hop packet udp".
Care should be taken while doing cutover between different types of devices that some options maybe not present in new device or maybe have to configure again. If we care about these things then we can get expected result everytime.