Particularly {HEAD ~ the source radio network control node} comprises {TAIL ~ an RNC} and the old packet data support node comprises a 3G SGSN or CGSN, whereas the target radio network control node is a BSS node and the new packet data support node is 2G SGSN or a CGSN 
comprises
Particularly { HEAD ~ the source radio network control node } comprises { TAIL ~ an RNC } and the old packet data support node comprises a 3 G SGSN or CGSN , whereas the target radio network control node is a BSS node and the new packet data support node is 2 G SGSN or a CGSN
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH