Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 659)

router or switch to have multiple containers of routing tables or Forwarding Information Bases (FIBs),
with one routing table for each VRF instance. This permits a VRF-capable router to function as a group
of multiple virtual routers on the same physical router.
Inter-VRF route leaking allows leaking of specific route prefixes from one VRF instance to another on
the same physical router, which eliminates the need for external routing. In a DHCP setting, route
leaking is controlled through a single DHCP server (which may be on a different VRF). This permits
multiple VRFs to communicate with that server.
The IP DHCP Relay is supported in configurations where the DHCP server is on the same or different
VRFs than the interface through which the client is connected. When the DHCP server and client are on
different VRFs, this is called inter-VRF deployment. For inter-VRF deployment, use the use-vrf vrf-name
option with the ip dhcp relay address command, where vrf-name is the VRF where the DHCP server is
located.
For more information on VRFs, refer to Virtual Routing and Forwarding configuration on page 609.
Supported VRF configuration examples
Following are examples of VRF configurations that are supported for IP DHCP Relay:
• Client interface and DHCP server are on same VRF. As an example:
‐ Ve interface 100 in red VRF
‐ IP address of interface - 3.1.1.1/24
‐ IP DHCP Relay address (20.1.1.2) in red VRF
• Client interface and DHCP servers are on different VRFs. As an example:
‐ Ve interface 100 in default VRF
‐ IP address of interface - 3.1.1.1/24
‐ IP DHCP Relay address (100.1.1.2) in blue VRF
‐ IP DHCP Relay address (1.2.3.4.6) in red VRF
A maximum of 128 of these inter-VRF IP DHCP Relay address configurations is allowed per node. A
VRF route leak configuration is required for these configurations. In the preceding example, a VRF
route leak configuration is required on the default VRF as follows:
‐ ip route 100.1.1.2/32 next-hop-vrf blue 100.1.1.2
‐ ip route 12.3.4.6/32 next-hop-vrf red 14.3.4.6
VRF configuration examples not recommended
The following examples of VRF configurations are not recommended for IP DHCP Relay.
• The same IP DHCP Relay address configured on different VRFs. As an example:
‐ Ve interface 100 in default VRF
‐ IP address of interface - 3.1.1.1/24
‐ IP DHCP Relay address (30.1.1.2) in blue VRF
‐ IP DHCP Relay address (30.1.1.2) in red VRF
• The same IP DHCP Relay address configured on two interfaces with the same address, and both
interfaces are on different VRFs. As an example:
‐ Ve interface 100 in default VRF
‐ IP address of interface - 3.1.1.1/24
‐ IP DHCP Relay address (20.1.1.2) in blue VRF
‐ Ve interface 200 in blue VRF
‐ IP address of interface - 3.1.1.1/24
‐ IP DHCP Relay address (20.1.1.2) in blue VRF
Configuring IP DHCP Relay
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