Lenovo Flex System Fabric CN4093, Application Manual

Page: 299 / 634

© Copyright Lenovo 2017
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Chapter 17. FCoE and CEE
This chapter provides conceptual background and configuration examples for
using Converged Enhanced Ethernet (CEE) features of the CN4093 10 Gb
Converged Scalable Switch, with an emphasis on Fibre Channel over Ethernet
(FCoE) solutions. The following topics are addressed in this chapter:
 “Fibre Channel over Ethernet” on page 300
Fibre Channel over Ethernet (FCoE) allows Fibre Channel traffic to be
transported over Ethernet links. This provides an evolutionary approach toward
network consolidation, allowing Fibre Channel equipment and tools to be
retained, while leveraging cheap, ubiquitous Ethernet networks for growth.

“FCoE Initialization Protocol Snooping” on page 305
Using FCoE Initialization Protocol (FIP) snooping, the CN4093 examines the
FIP frames exchanged between ENodes and FCFs. This information is used to
dynamically determine the ACLs required to block certain types of undesired
or unvalidated traffic on FCoE links.
 “Converged Enhanced Ethernet” on page 302
Converged Enhanced Ethernet (CEE) refers to a set of IEEE standards developed
primarily to enable FCoE, requiring enhancing the existing Ethernet standards
to make them lossless on a per ‐ priority traffic basis, and providing a mechanism
to carry converged (LAN/SAN/IPC) traffic on a single physical link. CEE
features can also be utilized in traditional LAN (non ‐ FCoE) networks to provide
lossless guarantees on a per ‐ priority basis, and to provide efficient bandwidth
allocation.

“Priority ‐ Based Flow Control” on page 312
Priority ‐ Based Flow Control (PFC) extends 802.3x standard flow control to
allow the switch to pause traffic based on the 802.1p priority value in each
packet’s VLAN tag. PFC is vital for FCoE environments, where SAN traffic
must remain lossless and must be paused during congestion, while LAN
traffic on the same links is delivered with “best effort” characteristics.

“Enhanced Transmission Selection” on page 316
Enhanced Transmission Selection (ETS) provides a method for allocating link
bandwidth based on the 802.1p priority value in each packet’s VLAN tag.
Using ETS, different types of traffic (such as LAN, SAN, and management)
that are sensitive to different handling criteria can be configured either for
specific bandwidth characteristics, low ‐ latency, or best ‐ effort transmission,
despite sharing converged links as in an FCoE environment.

“Data Center Bridging Capability Exchange” on page 322
Data Center Bridging Capability Exchange Protocol (DCBX) allows
neighboring network devices to exchange information about their
capabilities. This is used between CEE ‐ capable devices for the purpose of
discovering their peers, negotiating peer configurations, and detecting
misconfigurations.