Brocade Converged Enhanced Ethernet Administrator's Guide v6.1.2_cee (53-1001258-01, June 2009)

Converged Enhanced Ethernet Administrator’s Guide 5
53-1001258-01
Layer 2 Ethernet overview
1
FIGURE 2 Brocade 8000 CEE switch logical view
The FCoE VF_ports provide FC services to FCoE initiators and targets, as well as an FCoE-to-FC
bridging service that allows FCoE initiators to access FC targets and conversely, allows FC targets to
access FCoE initiators.
Brocade's implementation of FCoE for the Brocade 8000 CEE switch provides integral N_port ID
virtualization (NPIV) support. Multiple VN_port devices can log in to a single FCoE VF_port
interface. Up to 1,000 VN_port devices can log in to a single Brocade 8000 CEE switch.
Each of the embedded FCoE ports supports four logical traffic paths. These four logical traffic
paths share the FCoE port bandwidth. Any single traffic path may use the entire 10-Gbps of FCoE
port bandwidth if available, but it must share the bandwidth equally with the other logical path
traffic flows if more than one is active. The bandwidth available to any single logical traffic path
(and therefore any single FCoE-to-FC traffic flow) is between 2.5 Gbps and 10 Gbps.
While they share the FCoE port bandwidth, the logical traffic paths are independent from one
another in the event of downstream congestion. If the traffic flowing on one logical path stalls
because of congestion, the traffic flowing on the other logical paths on the same FCoE port is not
affected. Note however, that a logical traffic path is not limited to a single FCoE-to-FC traffic flow. If
multiple traffic flows are sharing the same logical traffic path, congestion independence between
the flows cannot be enforced.
Layer 2 Ethernet overview
In this section:
•Layer 2 forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
•VLAN tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
•Loop-free network environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
•Frame classification (incoming) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
•Congestion control and queuing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
•Access control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
•Trunking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
•Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Ethernet Switch
Six embedded
10-Gigabit
FCoE ports
24 10-Gigabit
Ethernet
CEE ports
Eight 8-Gigabit
FC ports
FC Switch