Specifications

DATA CENTER BEST PRACTICES
SAN Design and Best Practices 46 of 84
FCIP Trunking
The Brocade 7800 and FX8-24 have an exclusive feature called FCIP Trunking. FCIP Trunking offers the ability to
perform the following functions:
•Bandwidth aggregation
•Lossless failover/failback
•Granular load balancing
•In-order delivery
•Prevention of IFCC on mainframes
A single tunnel dened by a VE_Port or VEX_Port may have one or more circuits associated with it. A circuit
is an FCIP connection dened by a source and destination IP address and other arguments that dene its
characteristics, such as compression, IPsec, QoS, rate limit, VLAN tag, and others. All the circuits terminate at
the single VE/VEX_Port on each side; therefore, there are no multiple tunnels or ISLs, but only a single tunnel
load balanced across multiple circuits. The one ISL that an FCIP Trunk forms is from VE_Port to VE_Port or VEX_
Port to VE_Port.
The circuits can have different characteristics. They can have different RTTs and take different paths and
different service providers. They can have different bandwidths up to 4x. This means that if one circuit is an OC-
3, the most the other circuit(s) can be is OC-12, because the bandwidth delta is 4x.
FCIP Trunking is considered best practice in most cases. For example, consider the architecture shown in Figure
34. The FC perspective has already been discussed in detail. Here, consider the Ethernet/IP perspective and
how FCIP Trunking pertains to a high availability design.
fig34_SAN_Design
IP WAN link
Brocade
7800 4/2
Brocade
7800 4/2
Brocade
7800 4/2
Brocade
7800 4/2
Brocade
MLX core
Brocade
MLX core
Brocade
MLX core
Brocade
MLX core
FC path A
GbE
FCIP
GbE
FCIP
GbE
FCIP
GbE
FCIP
FC path B
FC path A
FC path B
Service Provider
Figure 34. Four Brocade 7800 High Availability Architecture.
Virtually all data centers have redundant IP core routers/switches. It is best practice to connect each Brocade
7800/FX8-24 to each of the IP core routers/switches for redundancy and resiliency purposes, as shown in
Figure 34. Without FCIP Trunking this design would require two VE_Ports per Brocade 7800 4/2. There are
two VE_Ports available in a 4/2; however, from a performance, resiliency, and redundancy point of view, this is
not the best solution. Instead, it is better to use a single VE_Port on the 4/2 with FCIP Trunking. The VE_Port
forms an FCIP tunnel with the opposing VE_Port, and there are two member circuits. Any FCIP tunnel with more
than one circuit is called an FCIP Trunk. FCIP circuits are assigned to Ethernet interfaces and, in this case,
each circuit is assigned to its own dedicated Ethernet interface. The Ethernet interfaces are then physically
connected to an Ethernet switch/IP core router. One of the Ethernet interfaces is connected to core A, and one
is connected to core B. Now there are two circuits that will load balance across both data center cores. With
FCIP Trunking, if any of the following occurs the result is no loss of data: core routers fail or have to go ofine for
maintenance, bad Ethernet SFP or optical cable, and sub-second failover within the WAN network.