Length field approach(DECNET) Use a header field to give the length of the frame(in bits or bytes) Receiver can count until the end of the frame to find the start of the next frame Receiver looks at the respective length field in the next packet header to find that packet's length Length field must be log,(Max_Size_Packet)+ 1 bits long This restricts the packet size to be used Issues with length counts Difficult to recover from errors Resynchronization is needed after an error in the length countLength field approach (DECNET) • Use a header field to give the length of the frame (in bits or bytes) – Rec eiver can count until the end of the frame to find the start of the next frame – Receiver looks at the respective length field in the next packet header to find t hat packet’s length • Length field must be log2 (Max_Size_Packet) + 1 bits long – This restricts the packet size to be used • Issues with length counts – Difficult to recover from errors – Res ynchronization is neede d after an error in the length count Eytan Modiano Slide 6