DSCP value 101110 looks like IP Precedence 5 to nonDiff Servcompliant devices

- Bits 5 to 7: "101" = 5 (Same three bits used for IP Precedence)

- Bits 3 to 4: "11" = drop probability high

The EF PHB is identified based on the following:

■ The EF PHB ensures a minimum departure rate. The EF PHB provides the lowest possible delay to delay-sensitive applications.

■ The EF PHB guarantees bandwidth. The EF PHB prevents starvation of the application if there are multiple applications using EF PHB.

■ The EF PHB polices bandwidth when congestion occurs. The EF PHB prevents starvation of other applications or classes that are not using this PHB.

■ Packets requiring EF should be marked with DSCP binary value "101110" (46 or 0x2E).

Non-DiffServ-compliant devices will regard EF DSCP value "101110" as IP Precedence 5 (101). This precedence is the highest user-definable IP Precedence and is typically used for delay-sensitive traffic (such as VoIP). Bits 5 to 7 of the EF DSCP value are "101," which matches IP Precedence 5 and allows backward compatibility.

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