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400-007 · Question #121

You have been tasked with designing a data center interconnect as part of business continuity. You want to use FCoE over this DCI to support synchronous replication. Which two technologies allow for…

The correct answer is A. DWDM C. SONET/SDH. FCoE requires lossless Ethernet (DCB) transport end-to-end; only physical/optical layer technologies like DWDM and SONET/SDH preserve these properties transparently across a DCI.

Designing Network Infrastructure

Question

You have been tasked with designing a data center interconnect as part of business continuity. You want to use FCoE over this DCI to support synchronous replication. Which two technologies allow for FCoE via lossless Ethernet or data center bridging? (Choose two.)

Options

  • ADWDM
  • BEoMPLS
  • CSONET/SDH
  • DMultichassis EtherChannel over Pseudowire
  • EVPLS

How the community answered

(55 responses)
  • A
    58% (32)
  • B
    5% (3)
  • D
    13% (7)
  • E
    24% (13)

Why each option

FCoE requires lossless Ethernet (DCB) transport end-to-end; only physical/optical layer technologies like DWDM and SONET/SDH preserve these properties transparently across a DCI.

ADWDMCorrect

DWDM operates at the optical physical layer and transports Ethernet frames transparently, preserving DCB features like Priority Flow Control (PFC) required for lossless FCoE without introducing packet-switching overhead or drop behavior.

BEoMPLS

EoMPLS is an MPLS-based pseudowire technology that does not natively support DCB features such as PFC, making lossless FCoE transport impossible.

CSONET/SDHCorrect

SONET/SDH provides circuit-switched, dedicated-bandwidth transport at the physical layer, delivering Ethernet frames without drops and maintaining the DCB properties necessary for FCoE synchronous replication over a DCI.

DMultichassis EtherChannel over Pseudowire

Multichassis EtherChannel over Pseudowire relies on MPLS pseudowires which lack native DCB and PFC support, preventing the lossless transport that FCoE requires.

EVPLS

VPLS is an MPLS-based Layer 2 VPN service that does not support DCB features, so it cannot guarantee the lossless Ethernet transport required for FCoE.

Concept tested: FCoE DCI transport over lossless DCB-capable technologies

Source: https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Data_Center/DCI.html

Topics

#FCoE#DCI#lossless Ethernet#DCB

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