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specification.md

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Specifications of ats-switch

This document describes specifications of the 4-port L2 switch with ATS implemented on FPGA.

Basic specifications

  • Support 1000BASE-T
    • Maximum designed speed is 1 Gbps
  • Supported Ethernet frame list
    • Ethernet II
    • IEEE 802.3ac
      • Vlan tag is supported
  • MTU is 1500 Byte
  • Support FDB
  • Detect flow from IPv4 header
  • Support ATS

Flow detection

  • The flow is detected from the following four fields in the IPv4 header of the input frame
    • Src IP address
    • Src port number
    • Dst IP address
    • Dst port number
  • There are 16 types of flows from 0 to 15
  • Which flow an input frame is detected to be is based on register settings
    • When all four fields in the input frame match the register settings, that flow is determined
    • Match confirmation is performed in order from flows 1 to 15, and when matched, the flow is confirmed
      • In other words, if multiple flow conditions are matched, the flow will have the lowest number
    • When it does not match any flow, it is determined to be flow 0
  • When the value 0 is set in the register, it is always detected to be matched regardless of the input frame value
  • Frames without IPv4 header like ARP are always detected to flow 0

Examples

Register settings
  • Flow = 1
    • src_ip = 192.168.1.1
    • src_port = 5201
    • dst_ip = 192.168.1.2
    • dst_port = 5202
  • Flow = 2
    • src_ip = 192.168.1.1
    • src_port 0
    • dst_ip = 192.168.1.2
    • dst_port = 5202
  • Flow = 3
    • src_ip = 0.0.0.0
    • src_port 0
    • dst_ip = 192.168.1.2
    • dst_port = 5202
  • Flow = 4 ~ 15
    • src_ip = 255.255.255.255
    • src_port 65535
    • dst_ip = 255.255.255.255
    • dst_port = 65535
Behavior
  • When the following frame is input, Flow = 1 will be detected
    • src_ip = 192.168.1.1
    • src_port = 5201
    • dst_ip = 192.168.1.2
    • dst_port = 5202
  • When the following frame is input, Flow = 2 will be detected
    • src_ip = 192.168.1.1
    • src_port = 5000
    • dst_ip = 192.168.1.2
    • dst_port = 5202
  • When the following frame is input, Flow = 3 will be detected
    • src_ip = 192.168.1.3
    • src_port = 5201
    • dst_ip = 192.168.1.2
    • dst_port = 5202
  • When the following frame is input, Flow = 0 will be detected
    • src_ip = 192.168.1.1
    • src_port = 5201
    • dst_ip = 192.168.1.2
    • dst_port = 5203

ATS behavior

  • ATS means Asynchronous Traffic Shaping algorithm
  • ATS behavior conform to IEEE Std 802.1Q-2022 8.6.11 ATS Scheduler state machines
  • ATS has following parameters
    • CommittedInformationRate
    • CommittedBurstSize
    • MaxResidenceTime
  • The parameters can set independently per input port, priority and flow
    • However, MaxResidenceTime is shared between flows
  • Internally, time is managed as unsigned integer 72 bit
    • The value is zero when the power is turned on, and is incremented by 8,000 every 8 ns
    • Overflow will occur, but only 149 years after the power is turned on
      • 2^72 ps = 4.72+21 ps = 4.72+9 s = 54,657 days = 149 years

Table of PCP vs priority

PCP in vlan tag Priority (= Traffic class)
0 1
1 0
2 6
3 7
4 2
5 3
6 4
7 5
(No vlan tag) 1
  • Note: These values ​​can be changed by register settings
  • ⚠️ Must change settings when no communication is occurring

Register map

Name Address Type Initial value Description
detect_flow (Input Port = 0, Priority = 0) 0x0000_0000 - - Include following registers
├ src_ip (Flow = 1) ├ + 0x0000 Unsigned Integer 32 bit 255.255.255.255 Condition of Flow = 1: IPv4 Src IP address
├ src_port (Flow = 1) ├ + 0x0004 Unsigned Integer 16 bit 66535 Condition of Flow = 1: IPv4 Src port number
├ dst_ip (Flow = 1) ├ + 0x0008 Unsigned Integer 32 bit 255.255.255.255 Condition of Flow = 1: IPv4 Dst IP address
├ dst_port (Flow = 1) ├ + 0x000C Unsigned Integer 16 bit 66535 Condition of Flow = 1: IPv4 Dst port number
├ src_ip (Flow = 2) ├ + 0x0010 Unsigned Integer 32 bit 255.255.255.255 Condition of Flow = 2: IPv4 Src IP address
├ src_port (Flow = 2) ├ + 0x0014 Unsigned Integer 16 bit 66535 Condition of Flow = 2: IPv4 Src port number
├ dst_ip (Flow = 2) ├ + 0x0018 Unsigned Integer 32 bit 255.255.255.255 Condition of Flow = 2: IPv4 Dst IP address
├ dst_port (Flow = 2) ├ + 0x001C Unsigned Integer 16 bit 66535 Condition of Flow = 2: IPv4 Dst port number
... ... ... ... ...
├ src_ip (Flow = 15) ├ + 0x00E0 Unsigned Integer 32 bit 255.255.255.255 Condition of Flow = 15: IPv4 Src IP address
├ src_port (Flow = 15) ├ + 0x00E4 Unsigned Integer 16 bit 65535 Condition of Flow = 15: IPv4 Src port number
├ dst_ip (Flow = 15) ├ + 0x00E8 Unsigned Integer 32 bit 255.255.255.255 Condition of Flow = 15: IPv4 Dst Ip address
└ dst_port (Flow = 15) └ + 0x00EC Unsigned Integer 16 bit 65535 Condition of Flow = 15: IPv4 Dst port number
process_frame (Input Port = 0, Priority = 0) 0x0000_1000 - - Include following registers
├ committed_information_rate_inv (Flow = 0) ├ + 0x0000 Unsigned Integer 32 bit 0 Committed Information Rate of ATS algorithm: set in ps/Byte
├ committed_burst_size (Flow = 0) ├ + 0x0004 Unsigned Integer 32 bit 0 Committed Burst Size of ATS algorithm: set in Byte
├ committed_information_rate_inv (Flow = 1) ├ + 0x0008 Unsigned Integer 32 bit 0 Refer to committed_information_rate_inv (Flow = 0)
├ committed_burst_size (Flow = 1) ├ + 0x000C Unsigned Integer 32 bit 0 Refer to committed_burst_size (Flow = 0)
... ... ... ... ...
├ committed_information_rate_inv (Flow = 15) ├ + 0x0078 Unsigned Integer 32 bit 0 Refer to committed_information_rate_inv (Flow = 0)
├ committed_burst_size (Flow = 15) ├ + 0x007C Unsigned Integer 32 bit 0 Refer to committed_burst_size (Flow = 0)
└ max_residence_time └ + 0x0080 Unsigned Integer 72 bit All Hi Max Residence Time of ATS algorithm: set in ps
detect_flow (Input Port = 0, Priority = 1) 0x0000_2000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 0, Priority = 1) 0x0000_3000 - - Refer to process_frame (Input Port = 0, Priority = 0)
detect_flow (Input Port = 1, Priority = 0) 0x0000_4000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 1, Priority = 0) 0x0000_5000 - - Refer to process_frame (Input Port = 0, Priority = 0)
detect_flow (Input Port = 1, Priority = 1) 0x0000_6000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 1, Priority = 1) 0x0000_7000 - - Refer to process_frame (Input Port = 0, Priority = 0)
detect_flow (Input Port = 2, Priority = 0) 0x0000_8000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 2, Priority = 0) 0x0000_9000 - - Refer to process_frame (Input Port = 0, Priority = 0)
detect_flow (Input Port = 2, Priority = 1) 0x0000_A000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 2, Priority = 1) 0x0000_B000 - - Refer to process_frame (Input Port = 0, Priority = 0)
detect_flow (Input Port = 3, Priority = 0) 0x0000_C000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 3, Priority = 0) 0x0000_D000 - - Refer to process_frame (Input Port = 0, Priority = 0)
detect_flow (Input Port = 3, Priority = 1) 0x0000_E000 - - Refer to detect_flow (Input Port = 0, Priority = 0)
process_frame (Input Port = 3, Priority = 1) 0x0000_F000 - - Refer to process_frame (Input Port = 0, Priority = 0)
enable_pause_req_and_drop_enable 0x0001_0000 Boolean 1 bit False When True, enable pause_req of TEMAC
gpio_processing_delay_max 0x0002_0000 Unsigned Integer 72 bit 50000000 Processing Delay Max of ATS algorithm: set in ps
priority_mapper_0 0x5000_0000 - - -
├ priority (PCP = 0) ├ + 0x0000 Unsigned Integer 3 bit 1 Priority when PCP = 0
├ priority (PCP = 1) ├ + 0x0004 Unsigned Integer 3 bit 0 Priority when PCP = 1
├ priority (PCP = 2) ├ + 0x0008 Unsigned Integer 3 bit 6 Priority when PCP = 2
├ priority (PCP = 3) ├ + 0x000C Unsigned Integer 3 bit 7 Priority when PCP = 3
├ priority (PCP = 4) ├ + 0x0010 Unsigned Integer 3 bit 2 Priority when PCP = 4
├ priority (PCP = 5) ├ + 0x0014 Unsigned Integer 3 bit 3 Priority when PCP = 5
├ priority (PCP = 6) ├ + 0x0018 Unsigned Integer 3 bit 4 Priority when PCP = 6
├ priority (PCP = 7) ├ + 0x001C Unsigned Integer 3 bit 5 Priority when PCP = 7
└ priority (No vlan tag) └ + 0x0020 Unsigned Integer 3 bit 1 Priority when no vlan tag
priority_mapper_1 0x5001_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_2 0x5002_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_3 0x5003_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_4 0x5004_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_5 0x5005_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_6 0x5006_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_7 0x5007_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_8 0x5008_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_9 0x5009_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_10 0x500A_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_11 0x500B_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_12 0x500C_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_13 0x500D_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_14 0x500E_0000 - - ⚠️ Must be same as priority_mapper_0
priority_mapper_15 0x500F_0000 - - ⚠️ Must be same as priority_mapper_0

Note: How to set IP address

  • In oder to set "192.168.1.2" ("0xC0"."0xA8"."0x01"."0x02"), write "0xC0A80102"

Note: How to set committed_information_rate_inv

  • "committed_information_rate_inv" is the reciprocal value of Committed Information Rate
  • In order to set "100 Mbps", write "80,000 ps/Byte"
    • (8 bit/Byte) * 1,000,000 / (100 Mbps) = 80,000 ps/Byte
  • In order to set "50 Mbps", write "160,000 ps/Byte"
    • (8 bit/Byte) * 1,000,000 / (50 Mbps) = 160,000 ps/Byte

Note: How to set max_residence_time

  • As "max_residence_time" has 72 bits, write in three parts
    • 0x0080: Lower 32 bit
    • 0x0084: Middle 32 bit
    • 0x0088: Upper 8 bit

Note: How to set processing_delay_max

  • As "processing_delay_max" has 72 bits, write in three parts
    • 0x20000: Lower 32 bit
    • 0x20004: Middle 32 bit
    • 0x20008: Upper 8 bit