MVTX2601 Datasheet, PDF (48/91 Pages) Zarlink Semiconductor Inc – Unmanaged 24-Port 10/100 Mbps Ethernet Switch

MVTX2601
12.7.13 UCC – Unicast Congestion Control
• I²C Address h0B6, CPU Address: 50C
• Accessed by serial interface and I²C (R/W)
7
0
Unicast congest threshold
Data Sheet
Bit [7:0] :
• Number of frame count. Used for best effort dropping at B% when
destination port’s best effort queue reaches UCC threshold and shared
pool is all in use. Granularity 1 frame. (Default: h10 for 2 MB or h08 for
1 MB)
12.7.14 MCC – Multicast Congestion Control
• I²C Address h0B7, CPU Address: 50D
• Accessed by serial interface and I²C (R/W)
7
5
4
0
FC reaction prd
Multicast congest threshold
Bit [4:0]:
Bit [7:5]:
• In multiples of two. Used for triggering MC flow control when
destination multicast port’s best effort queue reaches MCC threshold.
(Default 0x10)
• Flow control reaction period (Default 2) Granularity 4 uSec.
12.7.15 PR100 – Port Reservation for 10/100 ports
• I²C Address h0B8, CPU Address 50E
• Accessed by serial interface and I²C (R/W)
7
4
3
0
Buffer low thd
SP Buffer reservation
Bit [3:0]:
Bits [7:4]:
• Per port buffer reservation.
• Define the space in the FDB reserved for each 10/100 port. Expressed
in multiples of 4 packets. For each packet 1536 bytes are reserved in
the memory.
• Expressed in multiples of 4 packets. Threshold for dropping all best
effort frames when destination port best efforts queues reach UCC
threshold and shared pool all used and source port reservation is at or
below the PR100[7:4] level. Also the threshold for initiating UC flow
control.
• Default:
• h58 for configuration with 2 MB;
• h35 for configuration with 1 MB;
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Zarlink Semiconductor Inc.