0 votes 0 votes iita asked Jan 30, 2017 iita 768 views answer comment Share Follow See all 22 Comments See all 22 22 Comments reply Rahul Jain25 commented Jan 30, 2017 reply Follow Share Both are false. 0 votes 0 votes iita commented Jan 30, 2017 reply Follow Share they have given as C I think they are confused MF of last fragment is 0 and offset of first fragment is 0 right..?? 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share @rahul why both are not true? 0 votes 0 votes Rahul Jain25 commented Jan 30, 2017 reply Follow Share I think offset are per packet which are further fragmented. So when we talk about parent of 1st fragment it means last fragment of previous packet correct??? And MF for last fragment should be 0 right and parent means its previous will not be last so MF should be 1. @sudhso is C correct??? 0 votes 0 votes iita commented Jan 30, 2017 reply Follow Share offset means number of packets ahead of a perticular packets hence offsets of two packets can't be same 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share ^ offset means number of databytes ahead not packet yes rahul c is right...these points are infact used for reassembling the fragments.. 0 votes 0 votes Rahul Jain25 commented Jan 30, 2017 reply Follow Share No offset indicates size of payload in fragment I think. A singles packet can be fragment and each will have offset indicate payload in it. 0 votes 0 votes Rahul Jain25 commented Jan 30, 2017 reply Follow Share @sudhsho what do they mean by parent in I)??? 0 votes 0 votes Dulqar commented Jan 30, 2017 reply Follow Share How come C is right ? MF of last fragment will always be 0 ? MF denote More Fragments if any 0 votes 0 votes iita commented Jan 30, 2017 reply Follow Share are they considering the case that the packets are being further divided...??? 0 votes 0 votes Dulqar commented Jan 30, 2017 reply Follow Share On considering fragments of fragments Statment 1 is True . But Statement 2 is FALSE 0 votes 0 votes Rahul Jain25 commented Jan 30, 2017 reply Follow Share @sudsho I thought that for each packet the offset starts with 0. I understand about fragment that it indicate data before it. But when to talk about IP packets they must have offset starting from 0 correct?? 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share rahul depends...suppose initially u fragmented a packet into 88 , 88 ,148 etc fragments and ur 88 byte packet needs to cross a N/W with MTU 40...so u'll again divide 88 as 40,40,8..now for all these 3fragments 88 is the parent 0 votes 0 votes Dulqar commented Jan 30, 2017 reply Follow Share I got your point both stamtents are true 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share @dulkar if 2 is false...then in my above example how will u allot MF to all the 3 fragments 40,40,8? 1 votes 1 votes Rahul Jain25 commented Jan 30, 2017 reply Follow Share Yes I got the point C is answer. Thanks @sudhso 1 votes 1 votes iita commented Jan 30, 2017 reply Follow Share @sudhsho when 88 is divided as 40, 40 and then then 40 is the first packet so it will have same offset as 88 ...right...?? 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share yes....thats why parent and first fragment should have same offset and last 8 byte packet will have same MF as 88 1 votes 1 votes iita commented Jan 30, 2017 reply Follow Share if packets would not have been divided further then D would have been the case.. 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share ^ these 2 statements are always true....if 88 was not divided further then 88 was a fragment initially fr some other packet fr which these conditions will hold.... without these 2 statements u cant do reassembling of fragments 0 votes 0 votes iita commented Jan 30, 2017 reply Follow Share let's say 88 is the first fragment and it's not divided further so no databytes are ahead of it hence it's offset will be 0(since first packet) but the packet following 88 will have offset as 88..correct me if I am wrong 0 votes 0 votes sudsho commented Jan 30, 2017 reply Follow Share but the packet following 88 will have offset as 88 i already told u offset means no of databytes ahead of that particular fragment ...if packet is not fragmented then why previous packet of 88 will have offset as 88? we fragment a packet into fragments and give offset, MF etc to particular fragments of that packet....how fragments of a packet are identified?...using IDENTIFICATION no...please read fragmentation again u'll get it.. 0 votes 0 votes Please log in or register to add a comment.