BLADE OS™ Application Guide HP GbE2c Ethernet Blade Switch for c-Class BladeSystem Version 5.1 Advanced Functionality Software

Table Of Contents
BLADE OS 5.1 Application Guide
BMD00113, September 2009 Chapter 9: Basic IP Routing 169
Switch Name-Based Scheme
The switch option is the default scheme. Using this option, the switch name and port information
are inserted into the DHCP request as follows:
Using the DHCP Option 61 Client Identifier
For any non-trunked port: <switch name>-<port number>
For static trunk port: <switch name>-t<trunk ID>
For an LACP trunk port: <switch name>-k<Admin key>
Using the DHCP Option 82 Agent Identifiers
The switch name string is encoded in the Agent circuit ID sub-option.
The slot number and port number are encoded in the Agent remote ID sub-option, in
hexadecimal format:
<slot ID><port type><switch unit><port number, 2 bytes>
where:
Slot ID, 1 byte, is the switch slot ID.
Port type, 1 byte, is 0 for non-trunked ports, t for static trunk ports, or k for LACP ports.
Switch unit, 1 byte, is 0.
Port number, 2 bytes, is the port number for non-trunked ports, the trunk number for static
trunk ports, or the admin key for LACP trunk ports.
Virtual MAC-Based Scheme
Using the vmac option, the switch places a virtual MAC address in the DHCP request. The virtual
MAC address is generated for each port as follows:
<First five bytes of the switch’s base MAC address><virtual port ID>
where the virtual port ID is one of the following, depending on the port type:
For non-trunked ports: 0x40 plus the port number
For a port in a static trunk: 0x80 plus the port number.
For a port in an LACP trunk 0xa0 plus the port number.
For example, if the switch’s base MAC address is 00:e0:7b:1a:3c:00, then by varying the
last byte, non-trunked ports 1 through 24 are represented by virtual MAC addresses
00:e0:7b:1a:3c:41 through 00:e0:7b:1a:3c:58. Therefore port 7 will have a virtual
MAC of 00:e0:7b:1a:3c:47.