virtual tributary vt虚: void; emptiness支路: by-pass; by-trail; branching ...虚支路超帧: superframe虚支路封装容量: envelope capacity虚支路通路开销: path overhead下载手机词典可随时随地查词查翻译关注微信公众号：chachacidian，回复:虚支路，即可在微信中查询翻译
