tokens: ['GPP', 'specifies', 'GPP', 'NFs', 'in', 'terms', 'of', 'large', 'complex', 'lumps', 'of', 'functionality', 'which', 'span', 'multiple', 'physical', 'hardware', 'hosts', 'in', 'both', 'legacy', 'and', 'virtualised', 'implementations', 'While', 'there', 'is', 'a', 'risk', 'of', 'an', 'attacker', 'gaining', 'physical', 'access', 'to', 'the', 'interconnections', 'between', 'servers', 'making', 'up', 'a', 'single', 'PNF', 'this', 'generally', 'requires', 'physical', 'access', 'to', 'the', 'hardware', 'However', 'in', 'a', 'virtualised', 'environment', 'access', 'can', 'be', 'gained', 'much', 'more', 'easily', 'as', 'the', 'servers', 'making', 'up', 'a', 'function', 'are', 'more', 'likely', 'to', 'be', 'physically', 'distributed', 'and', 'as', 'the', 'SDN', 'vswitch', 'would', 'allow', 'an', 'attacker', 'to', 'much', 'more', 'easily', 'fork', 'IP', 'packets', 'flowing', 'between', 'hosts', 'remotely', 'Such', 'forking', 'is', 'very', 'difficult', 'to', 'detect', 'or', 'prevent', 'from', 'within', 'a', 'GPP', 'NF', 'or', 'VM', 'unless', 'specific', 'design', 'mitigation', 'is', 'taken', 'to', 'minimize', 'the', 'risk', 'While', 'TLS', 'automatically', 'applied', 'by', 'the', 'NFV', '', 'SDN', 'layer', 'between', 'VMs', 'reduces', 'external', 'attacker', 'threat', 'it', 'is', 'much', 'less', 'effective', 'against', 'attackers', 'who', 'have', 'or', 'have', 'gained', 'access', 'to', 'NFV', 'MANO', 'etc']