MVTX2801
Data Sheet
Bit [6]:
Bit [7]:
•
•
Select TOS bits for Priority (Default 0)
- 0 - Use TOS [4:2] bits to map the transmit priority
- 1 - Use TOS [5:3] bits to map the transmit priority
select TOS bits for Drop (Default 0)
- 0 - Use TOS [4:2] bits to map the drop priority
- 1 - Use TOS [5:3] bits to map the drop priority
10.6.3 FCR - Flooding Control Register
2
I C Address h040; Serial Interface Address:h502
2
Accessed by serial interface and I C (R/W)
7
6
4
3
0
Tos
TimeBase
U2MR
Bit [3:0]:
Bit [6:4]:
•
•
U2MR: Unicast to Multicast Rate. Units in terms of time base defined in bits [6:4]. This is used
to limit the amount of flooding traffic. The value in U2MR specifies how many packets are
allowed to flood within the time specified by bit [6:4]. To disable this function, program U2MR
to 0.
(Default = 4'h8)
TimeBase: (Default = 000)
- 000 = 10us
- 001 = 20us
- 010 = 40us
- 011 = 80us
- 100 = 160us
- 101 = 320us
- 110 = 640us
- 111 = 10us, same as 000.
Bit [7]:
•
Select VLAN tag or TOS field (IP packets) to be preferentially picked to map transmit priority
and drop priority (Default = 0).
- 0 - Select VLAN tag priority field over TOS field
- 1 - Select TOS field over VLAN tag priority field
10.6.4 AVPML - VLAN Priority Map
2
I C Address h041; Serial Interface Address:h503
2
Accessed by serial interface and I C (R/W)
7
6
5
3
2
0
VP2
VP1
VP0
Registers AVPML, AVPMM, and AVPMH allow the eight VLAN priorities to map into eight internal level transmit
priorities. Under the internal transmit priority, “seven” is the highest priority where as “zero” is the lowest. This
feature allows the user the flexibility of redefining the VLAN priority field. For example, programming a value of 7
into bit 2:0 of the AVPML register would map packet VLAN priority) into internal transmit priority 7. The new priority
is used only inside the 2801. When the packet goes out it carries the original priority.
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Zarlink Semiconductor Inc.
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
