TNETX4080 Datasheet, PDF (37/64 Pages) Texas Instruments – ThunderSWITCH IIE 8-PORT 10-/100-MBIT/S ETHERNETE SWITCH

TNETX4080
ThunderSWITCH II^™ 8-PORT 10-/100-MBIT/S ETHERNET^™ SWITCH
SPWS050A – AUGUST 1998 – REVISED NOVEMBER 1998
frame routing
VLAN support
The internal routing engine supports the IEEE Std 802.1Q VLANs as shown in Figure 6 and described in the
following paragraphs.
Receive
IEEE Std
802.1Q
Format
Frame
Header
Non-
IEEE Std
802.1Q
Format
Frame
If rxacc = 1
Header Inserted
If VLAN ID = 0x000
VLAN ID Replaced
Reset 0x0001
Header
Possibly
Inserted _Header
Inserted
Source Port’s Inserted
PortxQTag VLAN ID
Header
VLAN ID
Lookup
Queue
Manager
Destination
Port’s
PortxQTag
RAM
Queue
Manager
Reset to
All 0s
Source Address (SA)
Destination Address (DA)
VLAN ADDR
VLAN and
Ethernet
Addresses
Source
and
Destination
Lookups
Record
Number
Port Information
Port Numbers,
Time Stamps
Locked, Secure,
NBLCK, New
No
Match
Port
Information
VLANnQID
VLAN
Index
VLAN
Reset
1st Location:
No Match
0x001
All Others:
0x000
Source Port Number
SA
DA
Unicast/
Multicast
Port Routing Code
Frame-Routing
Algorithm
UnkUniPorts
UnkMultiPorts
UnkSrcPorts
UnkVLANPort
TxBlockPorts
RxUniBlockPorts
RxMultiBlockPorts
MirrorPort
UplinkPort
TrunkMapx
TrunkxPorts
NLearnPorts
Nauto
UnkVLAN
Lshare
Nage
Mirror
Disable
VLAN
Ports
Reset is
Don’t Care
SysControl
All Ports
PortxControl
Header
Compare
VLAN IDs
If (equal or
txacc = 1)
Then Strip Header,
Otherwise,
Keep Header
Header
Header _Stripped
Retained
IEEE Std
802.1Q
Format
Frame
Header
Non-
IEEE Std
802.1Q
Format
Frame
IALE
Reset to
All 1s
Transmit
Figure 6. VLAN Overview
VLANnPorts
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