KSZ8993M-EVAL Micrel Inc, KSZ8993M-EVAL Datasheet - Page 37

• Manufacturer Part Number: KSZ8993M-EVAL
• Description: KSZ8993M Evaluation Board - For Experimental Use Only
• Manufacturer: Micrel Inc

Specifications of KSZ8993M-EVAL

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Advanced VLAN features, such as “Ingress VLAN filtering” and “Discard Non PVID packets” are also supported
by the KSZ8993M. These features can be set on a per port basis, and are defined in register 18, bit 6 and bit 5,
respectively for port 1.
QoS Priority Support
This feature provides Quality of Service (QoS) for applications, such as VoIP and video conferencing. The
KSZ8993M per port transmit queue could be split into two priority queues: a high priority queue and a low priority
queue. Bit 0 of registers 16, 32 and 48 is used to enable split transmit queues for ports 1, 2 and 3, respectively.
Optionally, the Px_TXQ2 strap-in pins can be used to enable this feature. With split transmit queues, high priority
packets will be placed in the high priority queue and low priority packets will be placed in the low priority queue.
For split transmit queues, the KSZ8993M provides four priority schemes:
1. “Transmit all high priority packets before low priority packets;” i.e. a low priority packet could be transmitted
2. “Transmit high priority packets and low priority packets at 10:1 ratio;” i.e. transmit a low priority packet after
3. “Transmit high priority packets and low priority packets at 5:1 ratio”
4. “Transmit high priority packets and low priority packets at 2:1 ratio”
If a port's transmit queue is not split, both high priority packets and low priority packets have equal priority in the
transmit queue. Register 5 bits [3:2] are used to select the desired priority scheme. Optionally, the PRSEL1 and
PRSEL0 strap-in pins can be used.
Micrel, Inc.
October 2008
FID+SA found in Dynamic
MAC Table?
No
Yes
DA found in
Static MAC
Table?
No
No
Yes
Yes
Yes
Yes
only when the high priority queue is empty
every 10 high priority packets are transmitted, if both queues are busy
Use FID flag?
Don’t care
Don’t care
0
1
1
1
Action
Learn and add FID+SA to the Dynamic MAC Address Table
Update time stamp
Table 10. FID+SA Lookup in VLAN Mode
Table 9. FID+DA Lookup in VLAN Mode
FID match?
Don’t care
Don’t care
No
No
Yes
Don’t care
DA+FID
found in
Dynamic
MAC Table?
No
Yes
Don’t care
No
Yes
Don’t care
37
Action
Broadcast to the membership ports
defined in the VLAN Table bits [18:16]
Send to the destination port defined in the
Dynamic MAC Address Table bits [53:52]
Send to the destination port(s) defined in
the Static MAC Address Table bits [50:48]
Broadcast to the membership ports
defined in the VLAN Table bits [18:16]
Send to the destination port defined in the
Dynamic MAC Address Table bits [53:52]
Send to the destination port(s) defined in
the Static MAC Address Table bits [50:48]
M9999-020606
KSZ8993M/ML