Data Center Fabric Manager Enterprise User Manual v10.3.X (53-1001357-01, November 2009)

DCFM Enterprise User Manual 367

53-1001357-01

FCIP trunking overview

FCIP trunking is a method for managing the use of WAN bandwidth. Trunking is enabled by creating

logical circuits within an FCIP tunnel. A tunnel may have multiple circuits. Each circuit represents a

portion of the available Ethernet bandwidth provided by the GbE ports that are connected to the

WAN.

NOTE

FCIP trunking is available only on the 8 Gbps 16-FC ports, 6-Gbps ports extension switch and 8 Gbps

12-FC port, 10 GbE ports, 2-10 GbE ports blade. The 4 Gbps Router, Extension switch and blade do

not support FCIP trunking.

Figure 134 shows the relationship of trunks and circuits to VE_Ports, FCIP tunnels, and the physical

GbE interfaces. FC traffic enters and exits an FCIP tunnel on a VE_Port. Applications on the FC side

have no awareness of the existence of the FCIP tunnel. FCIP Trunking routes the FC traffic over FCIP

circuits. FCIP circuits route traffic over a WAN using any of the GbE interfaces. An FCIP circuit is a

logical connection between two peer switches or blades, so the same construct exists in each peer

switch or blade.

FIGURE 134 Basic overview of trunking components

Load leveling and failover using FCIP trunking

Each FCIP circuit is assigned a metric, which is used in managing load leveling and failover for FC

traffic. FCIP trunking uses the metric to determine if a circuit is to be used for load leveling or

failover. Figure 134 shows five circuits and their assigned metrics (0 or 1). Load leveling is

automatically done across circuits with the lowest metric. If a circuit fails, FCIP trunking tries first to

retransmit any pending send traffic over another lowest metric circuit. If no lowest metric circuits

are available, then the pending send traffic is retransmitted over any available circuits with the

higher metric.