Which two Any Transport over MPLS (AToM) traffic encapsulations require the use of a control
word? (Choose two)

A.
HDLC

B.
ATM AAL5

C.
PPP

D.
Ethernet VLAN

E.
Frame Relay

Explanation:
AToM Header
The AToM header is 4 bytes (control word). The control word is optional for Ethernet, PPP, HDLC,
and cell relay transport types. However, the control word is required for Frame Relay, and ATM
AAL5 transport types.