KSZ8864RMN Micrel Inc, KSZ8864RMN Datasheet - Page 29

• Manufacturer Part Number: KSZ8864RMN
• Description: IC ETHERNET SW 4PORT 64QFN
• Manufacturer: Micrel Inc

Specifications of KSZ8864RMN

• Controller Type: Ethernet Switch Controller
• Interface: MII, RMII
• Voltage - Supply: 1.8V, 2.5V, 3.3V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Supplier Unconfirmed
• Current - Supply: -
• Lead Free Status / RoHS Status: Supplier Unconfirmed, Lead free / RoHS Compliant
• Other names: 576-3787; KSZ8864RMN

January 2011
Aging
The look-up engine will update the time stamp information of a record whenever the corresponding SA appears. The
time stamp is used in the aging process. If a record is not updated for a period of time, the look-up engine will
remove the record from the table. The look-up engine constantly performs the aging process and will continuously
remove aging records. The aging period is 300 +/- 75 seconds. This feature can be enabled or disabled through
Register 3. See “Register 3” section.
Forwarding
The KSZ8864RMN will forward packets using an algorithm that is depicted in the following flowcharts. Figure 6
shows stage one of the forwarding algorithm where the search engine looks up the VLAN ID, static table, and
dynamic table for the destination address, and comes up with “port to forward 1” (PTF1). PTF1 is then further
modified by the spanning tree, IGMP snooping, port mirroring, and port VLAN processes to come up with “port to
forward 2” (PTF2), as shown in Figure 7. This is where the packet will be sent.
KSZ8864RMN will not forward the Following Packets:
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•
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Switching Engine
The KSZ8864RMN features a high-performance switching engine to move data to and from the MAC’s, packet
buffers. It operates in store and forward mode, while the efficient switching mechanism reduces overall latency. The
KSZ8864RMN has a 64kB internal frame buffer. This resource is shared between all five ports. There are a total of
512 buffers available. Each buffer is sized at 128B.
Media Access Controller (MAC) Operation
The KSZ8864RMN strictly abides by IEEE 802.3 standards to maximize compatibility.
Inter-Packet Gap (IPG)
If a frame is successfully transmitted, the 96-bit time IPG is measured between the two consecutive MTXEN. If the
current packet is experiencing collision, the 96-bit time IPG is measured from MCRS and the next MTXEN.
Backoff Algorithm
The KSZ8864RMN implements the IEEE Std. 802.3 binary exponential back-off algorithm, and optional “aggressive
mode” back off. After 16 collisions, the packet will be optionally dropped depending on the chip configuration in
Register 3. See “Register 3.”
Late Collision
If a transmit packet experiences collisions after 512-bit times of the transmission, the packet will be dropped.
Illegal Frames
The KSZ8864RMN discards frames less than 64 bytes and can be programmed to accept frames up to 1536 bytes in
Register 4. For special applications, the KSZ8864RMN can also be programmed to accept frames up to 1916 bytes
in Register 4. Since the KSZ8864RMN supports VLAN tags, the maximum sizing is adjusted when these tags are
present.
Flow Control
The KSZ8864RMN supports standard 802.3x flow control frames on both transmit and receive sides.
On the receive side, if the KSZ8864RMN receives a pause control frame, the KSZ8864RMN will not transmit the next
normal frame until the timer, specified in the pause control frame, expires. If another pause frame is received before
the current timer expires, the timer will be updated with the new value in the second pause frame. During this period
(being flow controlled), only flow control packets from the KSZ8864RMN will be transmitted.
Error packets. These include framing errors, FCS errors, alignment errors, and illegal size packet errors.
802.3x pause frames. The KSZ8864RMN will intercept these packets and perform the appropriate actions.
“Local” packets. Based on destination address (DA) look-up. If the destination port from the look-up table
matches the port where the packet was from, the packet is defined as “local.”
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