High Performance Two Port 10/100 Managed Ethernet Switch with
Datasheet
both are set to the same value, VLAN1 is given higher precedence and the maximum legal frame length is set to 1522.
Standard Ethernet Frame (1518 Bytes)
Preamble | SOF | Dest. Addr. | Source Addr. | Type | Data | FCS |
7 Bytes | 1 Byte | 6 Bytes | 6 Bytes | 2 Bytes | 4 Bytes |
Ethernet Frame with VLAN TAG (1522 Bytes)
Preamble | SOF | Dest. Addr. | Source Addr. | TPID | Type | Type | Data | FCS |
7 Bytes | 1 Byte | 6 Bytes | 6 Bytes | 2 Bytes | 2 Bytes | 2 Bytes | 4 Bytes |
Tag Control Information
(TCI)
TPID | User Priority | CFI |
| VLAN ID |
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2 Bytes | 3 Bits | 1 Bit |
| 12 Bits |
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| Defines the VLAN to | |
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| Canonical Address Format Indicator | |||
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Indicates the frame’s priority
Tag Protocol ID:
Figure 9.1 VLAN Frame
9.4Address Filtering
The Ethernet address fields of an Ethernet packet consist of two
The Host MAC address check logic filters the frame based on the Ethernet receive filter mode that has been enabled. The various filter modes of the Host MAC are specified based on the state of the control bits in the Host MAC Control Register (HMAC_CR), as shown in Table 9.1. Please refer to the Section 14.3.1, "Host MAC Control Register (HMAC_CR)," on page 270 for more information on this register.
If the frame fails the filter, the Host MAC does not receive the packet. The host has the option of accepting or ignoring the packet.
Note: This filtering function is performed after any switch fabric filtering functions. The user must ensure the switch filtering is setup properly to allow packets to be passed to the Host MAC for further filtering.
Revision 1.4 | 114 | SMSC LAN9312 |
| DATASHEET |
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