Other Techniques
RTNR (Real-Time Network Routing)
- current-generation routing algorithm (replaced DNHR in ATT switches in 1991)
- distributed control
- each switch measure load on all outgoing trunks
- to make decision, originator asks destination for its trunk loading list, takes logical AND of the two lists and chooses path (which is symmetric)
- about 1 or 2 blocked in core (of 260 million)