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Asset ID: 1-71-1005605.1
Update Date:2011-05-18
Keywords:

Solution Type  Technical Instruction Sure

Solution  1005605.1 :   Understanding which network interface will be used for a network boot on Sun SPARC(R) systems  


Related Items
  • Sun Fire E25K Server
  •  
  • Sun Fire E20K Server
  •  
  • Sun Fire 12K Server
  •  
  • Sun Fire 15K Server
  •  
  • Sun Enterprise 10000 Server
  •  
Related Categories
  • GCS>Sun Microsystems>Servers>High-End Servers
  •  

PreviouslyPublishedAs
207781


Applies to:

Sun Enterprise 10000 Server
Sun Fire 12K Server
Sun Fire 15K Server
Sun Fire E20K Server
Sun Fire E25K Server
All Platforms

Goal

When network booting a SPARC(R) system, it's important to know which interface will be used for the boot.

This document seeks to address answering not only which port will be used, but how to determine which ports are available for use and the ethernet (MAC address) associated with these interfaces.

This document is part of resolution path described into 1012870.1: Troubleshooting Common JumpStart[TM] Problems: "Timeout waiting for ARP/RARP packet"

Solution

When network booting, the first part of the process is for the Client system to send out an Reverse Address Resolution Protocol request (RARP request) to request the corresponding IP address from the boot server.

It's important to know which interface will be used, as this can influence which ethernet address is sent onto the network.

The local-mac-address setting in the OBP controls whether the system uses the system's ethernet address, as displayed by the OBP banner command, or uses the ethernet address associated with each specific interface.

To check if the system wide MAC address will be used:

    {8} ok printenv local-mac-address
    local-mac-address  =    true

This means that the system will use the interface specific MAC address (ethernet address) when broadcasting it's RARP request. This is typically the desired behaviour.

If set to false, then ALL interfaces would use the system's ethernet address, which is not desirable if any of these interfaces are to be connected to the same network.

When network booting, the boot command is typically

    {8}ok boot net

It should be noted, however, that this is actually instructing the system to boot from the device alias 'net'.

To check what the current 'net' alias is at the OBP:  

    ok devalias net
    net                      /pci@7c0/pci@0/network@4

In the event that there are multiple ethernet devices in the system, and the device paths are now known, they can be checked in the Sun[TM] System Handbook, by following the links to your specific platform.

See the Sun[TM] System Handbook and related platform specific documentation for your platform on https://support.oracle.com/handbook_private to determine the physical locations and device paths for your system.

Alternately, one can plug an interface into the network, and watch each connection in series to determine which port has been connected to the network.

An example on a T5210 follows:

To check what the available network device paths are, at the OBP:

show-nets

    {8} ok show-nets
    a) /pci@0/pci@0/pci@1/pci@0/pci@3/network@0,1
    b) /pci@0/pci@0/pci@1/pci@0/pci@3/network@0
    c) /pci@0/pci@0/pci@1/pci@0/pci@2/network@0,1
    d) /pci@0/pci@0/pci@1/pci@0/pci@2/network@0
    q) NO SELECTION
    Enter Selection, q to quit: q
    {8} ok

And to check which of these are connected to a network, on a SPARC system,

    {8} ok watch-net-all
    /pci@0/pci@0/pci@1/pci@0/pci@3/network@0,1
    Timed out waiting for Autonegotation to complete
    Check cable and try again
    Link Down
    /pci@0/pci@0/pci@1/pci@0/pci@3/network@0
    Timed out waiting for Autonegotation to complete
    Check cable and try again
    Link Down
    /pci@0/pci@0/pci@1/pci@0/pci@2/network@0,1
    Timed out waiting for Autonegotation to complete
    Check cable and try again
    Link Down
    /pci@0/pci@0/pci@1/pci@0/pci@2/network@0
    1000 Mbps full duplex  Link up
    Looking for Ethernet Packets.
    '.' is a Good Packet.  'X' is a Bad Packet.
    Type any key to stop.
    ....................................................

From here, it is clear that only /pci@0/pci@0/pci@1/pci@0/pci@2/network@0 is connected to a network, and can see packets. As this is the only interface plugged in, this would be the port to use for our network boot.

Check the local MAC address of this interface by cd'ing to it's pathname in the OBP

    {8} ok cd /pci@0/pci@0/pci@1/pci@0/pci@2/network@0

and checking it's properties.

    {8} ok .properties
    local-mac-address        00 14 4f 46 52 30
    mac-addresses            00 14 4f 46 52 30
    <...>

To set the 'net' device alias to this interface, you would use the following:

    nvalias net /pci@0/pci@0/pci@1/pci@0/pci@2/network@0

and could then

    {8} ok boot net

knowing that this interface would send out ethernet address 00:14:4f:46:52:30 onto the subnet we are connected to. Note that the 0 padding should NOT be included in the nameservice entry, this this entry should appear as  0:14:4f:46:52:30

Alternately, if this is to be a one time boot, one could simply boot from the device path itself:

    boot /pci@0/pci@0/pci@1/pci@0/pci@2/network@0



Product
Sun Fire E25K Server
Sun Fire E20K Server
Sun Fire 15K Server
Sun Fire 12K Server
Sun Enterprise 10000 Server


Internal Section

Keywords: SPARC, solaris, jumpstart, net boot, net-boot, arp, rarp

Previously Published As 90570



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