Which of the following are possible criteria for classifying packets at the network port ingress on the Alcatel-Lucent 7750 SR? (Choose three)

Question

Options

• AThe EXP bits in the MPLS header.
• BThe packet's source and destination IP addresses.
• CThe packet's DSCP bits.
• DThe dot1p bits in the frame header.
• EThe ID of an SDP that is transporting the packet.

• A
  86% (51)
• B
  8% (5)
• E
  5% (3)

Explanation

On the 7750 SR, network port ingress classification operates on header-level QoS marking bits embedded directly in the packet frame. EXP bits (A) mark traffic class within MPLS-labeled packets, DSCP bits (C) mark QoS in the IP header, and dot1p bits (D) carry priority in the Ethernet/VLAN frame header - all three are inspectable at the moment a packet arrives on a network port.

Why B is wrong: Source/destination IP addresses are used in filter/ACL policies, not in the network port QoS ingress classification context this question targets. IP address-based classification belongs to a different policy mechanism.

Why E is wrong: An SDP (Service Distribution Point) is a logical tunnel abstraction - it doesn't exist as a field in an incoming packet header. The SDP identity is resolved after ingress processing, so it cannot serve as an ingress classification criterion.

Memory tip: Think "3 Bits at the Gate" - the 7750 SR reads three sets of QoS bits as packets enter the network port: EXP (MPLS), DSCP (IP), Dot1p (Ethernet). If it's a bit field in a header, it qualifies; if it's an address or logical construct, it doesn't.

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