By flexible Abis in Ericsson can save efficeintly the bandwidth and GSL devices .
good point from optimization point of view is that if we have more number of users in once cell in a site and less in ohter cell in the same site no need to upgrade the the E1 or incrased the capacity the EDGE /GPRS all the cells which are conneted to the one site will feed the amount Data traffic from same pool .