The layer 2 protocol used by POS technology offers a standardized way for mapping IP packets
into SONET/ SDH payloads. Select the correct sequence of POS operation:
1) Data is scrambled and synchronous mapping takes place by octet into the SONET/SDH frame.
2) Encapsulated via Point-to-Point Protocol (PPP) takes place framing information is added with
High-level
Data Link Control (HDLC).
3) Gaps between frames are filled with flags, set to value 7E.
4) Octet stuffing occurs if any flags or resultant escape characters (of value 7D) are found in the
data.
5) Data is segmented into an IP datagram with its 20-byte IP header.
A.
1, 3, 4, 5, 2
B.
5, 2, 3, 1, 4
C.
2, 3, 5, 4, 1
D.
5, 2, 3, 4, 1
E.
1, 2, 3, 4, 5
Explanation:
The proper order of operation of PoS is:
When transmitting:
IP -> PPP -> FCS generation -> Byte stuffing -> Scrambling -> SONET/SDH framing
When receiving:
SONET/SDH framing -> Descrambling -> Byte destuffing -> FCS detection -> PPP -> IP
Remote