Ptp Message Detection; Table 11.3 Ptp Multicast Addresses - SMSC LAN9311i Datasheet

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface
Datasheet
11.2.2

PTP Message Detection

In order to provide the most flexibility, loose packet type matching is used by the LAN9311/LAN9311i.
This assumes that for all packets received with a valid FCS, only the MAC destination address is
required to qualify them as a PTP message. For Ethernet, four multicast addresses are specified in
the PTP protocol: 224.0.1.129 through 224.0.1.132. These map to Ethernet MAC addresses
01:00:5e:00:01:81 through 01:00:5e:00:01:84. Each of these addresses has one enable bit per port in
the 1588 Configuration Register (1588_CONFIG)
as a PTP address on the specified port.
In addition to the fixed addresses, a user defined (host programmable) PTP address may be input via
the 1588 Auxiliary MAC Address High-WORD Register (1588_AUX_MAC_HI)
Address Low-DWORD Register
disabled/enabled as a PTP address on each port via the dedicated enable bits in the
Configuration Register
corresponding enable bits can be seen in
PTP ADDRESS
224.0.1.129
(Primary)
224.0.1.130
(Alternate 1)
224.0.1.131
(Alternate 2)
224.0.1.132
(Alternate 3)
User Defined
Once a packet is determined to match a PTP destination address, it is further qualified as a Sync or
Delay_Req message type. On Ethernet, PTP uses UDP messages. Within the UDP payload is the PTP
control byte (offset 32 starting at 0). This byte determines the message type: 0x00 for a Sync message,
0x01 for a Delay_Req message. The UDP payload starts at packet byte offset 42 (from 0) for untagged
packets and at byte offset 46 for tagged packets.
Note: Both tagged and untagged packets are supported. Only Ethernet II packet encoding and IPv4
are supported.
Note: For proper routing of the PTP packets, the host must program an entry into the switch engine
Address Logic Resolution (ALR) Table. The MAC address should be one of the reserved
Multicast addresses in
bits must also be set. Refer to
SMSC LAN9311/LAN9311i
(1588_AUX_MAC_LO). The user defined address may be
(1588_CONFIG). A summary of the supported PTP multicast addresses and
Table 11.3.

Table 11.3 PTP Multicast Addresses

CORRESPONDING
MAC ADDRESS
01:00:5e:00:01:81
01:00:5e:00:01:82
01:00:5e:00:01:83
01:00:5e:00:01:84
User Defined Address
(1588_AUX_MAC_HI &
1588_AUX_MAC_LO registers)
Table 11.3, with Port 0(Host MAC) as a destination.The Static and Valid
Chapter 6, "Switch Fabric," on page 55
159
DATASHEET
which enables/disables the corresponding address
RELATED ENABLE BITS IN THE
1588_CONFIG REGISTER
MAC_PRI_EN_1 (Port 1)
MAC_PRI_EN_2 (Port 2)
MAC_PRI_EN_MII (Port 0)
MAC_ALT1_EN_1 (Port 1)
MAC_ALT1_EN_2 (Port 2)
MAC_ALT1_EN_MII (Port 0)
MAC_ALT2_EN_1 (Port 1)
MAC_ALT2_EN_2 (Port 2)
MAC_ALT2_EN_MII (Port 0)
MAC_ALT3_EN_1 (Port 1)
MAC_ALT3_EN_2 (Port 2)
MAC_ALT3_EN_MII (Port 0)
MAC_USER_EN_1 (Port 1)
MAC_USER_EN_2 (Port 2)
MAC_USER_EN_MII (Port 0)
and 1588 Auxiliary MAC
1588
for more information.
Revision 1.4 (08-19-08)