User Manual

Rev 2.2-1.0.1

Mellanox Technologies

4.4.3 IPoIB Configuration

Unless you have run the installation script mlnxofedinstall with the flag ‘-n’, then IPoIB has

not been configured by the installation. The configuration of IPoIB requires assigning an IP

address and a subnet mask to each HCA port, like any other network adapter card (i.e., you need

to prepare a file called ifcfg-ib<n> for each port). The first port on the first HCA in the host is

called interface ib0, the second port is called ib1, and so on.

An IPoIB configuration can be based on DHCP (Section 4.4.3.1) or on a static configuration

(Section 4.4.3.2) that you need to supply. You can also apply a manual configuration that persists

only until the next reboot or driver restart (Section 4.4.3.3).

4.4.3.1 IPoIB Configuration Based on DHCP

Setting an IPoIB interface configuration based on DHCP is performed similarly to the configura-

tion of Ethernet interfaces. In other words, you need to make sure that IPoIB configuration files

include the following line:

For RedHat:

BOOTPROTO=dhcp

For SLES:

BOOTPROTO=’dchp’

If IPoIB configuration files are included, ifcfg-ib<n> files will be installed under:

/etc/sysconfig/network-scripts/ on a RedHat machine

/etc/sysconfig/network/ on a SuSE machine.

A patch for DHCP may be required for supporting IPoIB. For further information,

please see the REAME which is available under the docs/dhcp/ directory.

Standard DHCP fields holding MAC addresses are not large enough to contain an IPoIB hard-

ware address. To overcome this problem, DHCP over InfiniBand messages convey a client iden-

tifier field used to identify the DHCP session. This client identifier field can be used to associate

an IP address with a client identifier value, such that the DHCP server will grant the same IP

address to any client that conveys this client identifier

The length of the client identifier field is not fixed in the specification. For the Mellanox OFED

for Linux package, it is recommended to have IPoIB use the same format that FlexBoot uses for

this client identifier – see Section A.3.2, “Configuring the DHCP Server”, on page 259.

4.4.3.1.1 DHCP Server

In order for the DHCP server to provide configuration records for clients, an appropriate config-

uration file needs to be created. By default, the DHCP server looks for a configuration file called

dhcpd.conf under /etc. You can either edit this file or create a new one and provide its full

path to the DHCP server using the -cf flag (See a file example at

docs/dhcpd.conf).

The DHCP server must run on a machine which has loaded the IPoIB module.

To run the DHCP server from the command line, enter:

dhcpd <IB network interface name> -d