ASN.1/BER (you really mean BER) is the example most protocol dorks bring up when they argue against IDLs and structured protocols. It's incredibly complicated (though not as hard to implement as CORBA/IIOP).
indeed. i have used ASN.1 for a bunch of SNMP and GGSN accounting stuff, it is a pita. xdr on the other hand, is a breeze. also, xdr does support variable length fields.
