IP协议对应于。SI参考模型的第（ ）层。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='29470' and id < 2398752 and id<>'2398752' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='29470' and id > 2398752 and id<>'2398752' order by id asc limit 5