FOS-90x-Ext-UG100 User Guide
Brocade
®
Fabric OS
®
Extension User Guide, 9.0.x
IP-routable Yes
For additional information about implementation and technical details of Brocade Extension technology, refer to the
Brocade white paper Extension Trunking.
Extension Trunks, Tunnels, Circuits, and Interfaces
An extension tunnel is a conduit that contains one or more circuits. When a tunnel contains multiple circuits, it is also
called an extension trunk because multiple circuits are trunked together. An extension tunnel, or extension trunk, is a
single interswitch link (ISL). Circuits are individual extension connections within the trunk, each with its own unique source
and destination IP interface (IPIF) address.
To understand tunnels, you must understand the relationship between tunnels and VE_Ports. Because an extension
tunnel is an ISL, each end of the tunnel requires its own Virtual E_Port (VE_Port). For example, the Brocade SX6 Blade
supports a number of VE_Ports. The available VE_Ports on the Brocade SX6 Blade are numbered 16 to 35. Tunnels are
more complicated than this, but the point is that each end of the tunnel is identified by number, and that number is directly
associated with a VE_Port on the extension platform. Tunnels are frequently created between different VE_Ports, so from
a configuration point of view, the tunnel number can be different at each end. Each extension platform (Brocade 7810
Switch and Brocade SX6 Blade) has a different numbering scheme for its VE_Ports.
Circuits exist within tunnels. A circuit is a connection between a pair of IP addresses that is defined within an extension
tunnel. Circuits provide the links for traffic flow between source and destination interfaces that are located on either end of
the tunnel. Each tunnel can contain a single circuit or multiple circuits.
NOTE
In this publication, the source or local is the switch that you are configuring, whereas the destination or remote is
the switch on the other end of the tunnel or circuit. Local switch and remote switch will depend on which side of
the of the tunnel you are configuring.
You must configure unique IPIFs as the local and remote endpoints of each circuit. On the local side, a circuit is
configured with a source IPIF address and a destination address. On the remote side of the circuit, its source IPIF address
is the same as the local-side destination address. Similarly, on the remote side of the circuit, its IPIF destination address
points to the local-side source address. Multiple IPIFs can be configured on each physical Ethernet interface.
NOTE
On the Brocade 7810 Switch and Brocade SX6 Blade, each address pair must be unique. For example, the
following address pairs use the same source address in each pair, but the destination addresses differ and each
address pair is unique.
•
--local-ip 10.0.1.10 --remote-ip 10.1.1.10
•
--local-ip 10.0.1.10 --remote-ip 10.1.1.11
The circuit configuration parameters on the local and remote sides of the circuits and tunnel must match, in addition to the
source and destination IPIF addresses pointing to each other. For example, if you configure IPsec on a tunnel, each end
of the tunnel must be configured to use the same IPsec parameters. Other parameters for each circuit must match, such
as MTU size, bandwidth allocation, QoS, and keepalive values.
You must configure a gateway IP route for the circuit to the destination network when the remote IPIF is not on the same
subnet as the local IPIF. You can define a specific number of routes per IPIF based on the extension platform. See Tunnel
and Circuit Requirements for Brocade Extension Platforms for specifications.
ATTENTION
When using the Brocade IP Extension, the local and remote LAN subnet addresses must be different.
The following figure shows an example of two extension tunnels. The first tunnel is a trunk of four circuits, and the second
tunnel is a trunk of two circuits. Each circuit is assigned a unique IPIF address. Those IPIFs are, in turn, assigned to
Ethernet interfaces. In the figure, each IPIF is assigned to a different Ethernet interface. This is not required. Ethernet
interface assignment is flexible depending on the environment's needs, and assignments can be made as desired. For
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