# QoS

Up to 7 transmit queues can be use to classify the packets before they are actually transmitted over the RF interface. Two of the RF transmit queues are used for packets coming from the serial ports of the Viper (one per serial port). The remaining 5 RF transmit queues are used for packets coming from the Ethernet interface. The user can specify filters to classify the packets coming from the Ethernet interface into any of the 5 remaining RF transmit queues. The 7 transmit queues can be configured for minimum guaranteed bitrate, maximum bitrate and maximum amount of packets that the queue can hold.

Packets generated by the Viper itself are sent into a hidden RF transmit queue (called the control transmit queue). This queue the user does not control.

## QoS

Enable or disable the QoS module. When the QoS module is disabled, there is only one RF transmit queue (packets are transmitted over the RF interface first come first served).

## Default LAN Queue

A packet coming from the Ethernet interface that must be sent over the RF interface will be put into the default transmit queue unless a specific filter is defined that indicates what RF transmit queue to use.

## RF Transmit Queue Configuration

Enable: The given RF transmit queue is in use of not. At least one LAN port queue must be enabled at all time.

Rate(%): The minimum guaranteed bit rate (expressed in percentage of the available bandwidth). A value of 0 means discard any packets sent to this queue.

Minimum value : 0 (%)

Maximum value : 100 (%)

Ceiling (%): The maximum bit rate (expressed in percentage of the available bandwidth).

Minimum value : 1 (%)

Maximum value : 100 (%)

Queue Size (packets): The maximum amount of packets the transmit queue can hold.

Minimum value : 1 (packet)

Maximum value : 128 (packets)

High Priority: When sending packets, the packet scheduler basically sends a packet from one transmit queue, moves on to the next transmit queue, sends one packet, moves on to the next transmit queue, etc. All of this is done while maintaining the configured throughputs per transmit queue. When the high priority queue is set, this queue will be processed first when transmitting and once every two times.

## Filters

The user can define up to 128 QoS filters to classify the packets in the various RF transmit queues.

The current packets fields that can be used for classifying are the following:

Ethernet Type:The ethernet type. This is only for bridge mode. (ARP=0x0806, IPv4=0x0800)

VLAN ID:The VLAN identifier (used in bridge mode when passing the full Ethernet packet AND used in router mode when VLAN is used).

Source IP Address: Use this to specify a range of IP address that will represent valid source IP addresses. (Example: 200.200.200.0/24, 200.200.200.1/32).

Source Port: The UDP/TCP source port number (a value of 0 means any value).

Destination IP Address: Use this to specify a range of IP address that will represent valid destination IP addresses. (Example: 200.200.200.0/24, 200.200.200.1/32).

Destination Port: The UDP/TCP destination port number (a value of 0 means any value).

DSCP: The "Differentiated Services Code Point" (6 most significant bits of the 8 bit TOS field in the IP header). Leave this field to "Any" if you do not care about this value.

DSCP
Value | Description
0 | CS0 - 000000 - Best Effort
8 | CS1 - 001000 - Class 1
16 | CS2 - 010000 - Class 2
24 | CS3 - 011000 - Class 3
32 | CS4 - 100000 - Class 4
40 | CS5 - 101000 - Express
48 | CS6 - 110000 - Reserved
10 | AF11 - 001010 - Class 1 Low
12 | AF12 - 001100 - Class 1 Medium
14 | AF13 - 001110 - Class 1 High
18 | AF21 - 010010 - Class 2 Low
20 | AF22 - 010100 - Class 2 Medium
22 | AF23 - 010110 - Class 2 High
26 | AF31 - 011010 - Class 3 Low
28 | AF32 - 011100 - Class 3 Medium
30 | AF33 - 011110 - Class 3 High
34 | AF41 - 100010 - Class 4 Low
36 | AF42 - 100100 - Class 4 Medium
38 | AF43 - 100110 - Class 4 High
46 | EF - 101110 - Expedited Forwarding

Protocol:The protocol number found in the IP header of the packet. Leave this field to "All" if you do not care about this value.

TCP ACK only:When this option is checked, look for TCP packets with a TCP header only (no TCP data) and only the ACK flag set.

Transmit Queue:The transmit queue to use by packets corresponding to all of the criteria in the filter.

## Filter Table

Before packets are transmitted over the RF interface, these filters are applied to determine the proper RF transmit queue to use. The filters are passed top down until a match is found. These filters only apply when the QoS module is enabled.