KSZ8862-16_10 MICREL [Micrel Semiconductor], KSZ8862-16_10 Datasheet - Page 43

• Manufacturer Part Number: KSZ8862-16_10
• Description: 2-Port Ethernet Switch with Non-PCI Interface and Fiber Support
• Manufacturer: MICREL [Micrel Semiconductor]

IEEE 802.1Q VLAN Support
The KSZ8862M supports 16 active VLANs out of the 4096 possible VLANs specified in the IEEE 802.1Q specification.
KSZ8862M provides a 16-entry VLAN table, which converts the 12-bits VLAN ID (VID) to the 4-bits Filter ID (FID) for
address lookup. If a non-tagged or null-VID-tagged packet is received, the ingress port default VID is used for lookup. In
VLAN mode, the lookup process starts with VLAN table lookup to determine whether the VID is valid. If the VID is not
valid, the packet is dropped and its address is not learned. If the VID is valid, the FID is retrieved for further lookup. The
FID + Destination Address (FID+DA) are used to determine the destination port. The FID + Source Address (FID+SA) are
used for address learning. (See Tables 10 and 11.)
QoS Priority Support
The KSZ8862M provides Quality of Service (QoS) for applications such as VoIP and video conferencing. Offering four
priority queues per port, the per-port transmit queue can be split into four priority queues: Queue 3 is the highest priority
queue and Queue 0 is the lowest priority queue. Bit 0 of registers P1CR1, P2CR1, and P3CR1 is used to enable split
transmit queues for ports 1, 2, and the host port, respectively.
Port-Based Priority
With port-based priority, each ingress port is individually classified as a high-priority receiving port. All packets received at
the high-priority receiving port are marked as high priority and are sent to the high-priority transmit queue if the
corresponding transmit queue is split. Bit 4 and 3 of registers P1CR1, P2CR1, and P3CR1 is used to enable port-based
priority for ports 1, 2, and the host port, respectively.
802.1p-Based Priority
For 802.1p-based priority, the KSZ8862M examines the ingress (incoming) packets to determine whether they are tagged.
If tagged, the 3-bit priority field in the VLAN tag is retrieved and compared against the “priority mapping” value, as
specified by the register SGCR6. The “priority mapping” value is programmable.
Micrel, Inc.
August 2010
FID+SA found in Dynamic MAC Table?
No
Yes
DA found in
Static MAC
Table?
No
No
Yes
Yes
Yes
Yes
Use FID flag?
Don’t care
Don’t care
0
1
1
1
Table 10. FID+DA Lookup in VLAN Mode
Table 11. FID+SA Lookup in VLAN Mode
Don’t care
FID match?
Don’t care
Don’t care
No
No
Yes
DA+FID found in
Dynamic MAC
Table?
No
Yes
Don’t care
No
Yes
Don’t care
Action
Learn and add FID+SA to the Dynamic MAC Address Table
Update time stamp
43
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]
KSZ8862-16/32MQL
M9999-081310-3.1