RuggedCom RuggedRouter RX1100 - Manual (Page 137)

15. Traffic Control
Revision 1.14.3 137 RX1000/RX1100™
15. Traffic Control
15.1. Traffic Control (TC) Fundamentals
Traffic Control is a subsystem of the firewall that allows management of the amount of bandwidth per
network interface that different types of traffic are permitted to use.
Each interface to be managed is assigned a total bandwidth that it should allow for incoming and
outgoing traffic. Classes are then defined for each interface, each with its own minimum assured
bandwidth and a maximum permitted bandwidth. The combined minimum of the classes on an
interface must be no more than the total outbound bandwidth specified for the interface. Each
class is also assigned a priority, and any bandwidth left over after each class has received its
minimum allocation (if needed) will be allocated to the lowest priority class up until it reaches its
maximum bandwidth, after which the next priority is allocated more bandwidth. When the specified
total bandwidth for the interface is reached, no further packets are sent, and any further packets may
be dropped if the interface queues are full.
Packets are assigned to classes on the outbound interface based on either a mark assigned to the
packet, or the ToS (type of service) field in the IP header. If the ToS field matches a defined class,
then the packet is allocated to that class. Otherwise, it is allocated to any class that matches the
mark assigned to the packet, and if no class matches the mark, then the packet is assigned to the
default class.
Marks are assigned to packets either by the TC Rules based on any of a number of parameters, such
as IP address, port number, protocol, packet length, and so on, or by mapping an 802.1p VLAN CoS
value to a MARK in the VLAN configuration of the incoming port. Marks are also used to map back
to an 802.1p CoS value on an outbound VLAN port.
15.1.1. Traffic Control Example
The goal of this example is to operate Ethernet port 1 at 5Mbit/s and ensure that UDP source port
20000 traffic gets at least half the bandwidth, while ICMP and TCP ACK packets should have high
priority, HTTP traffic gets at least 20% and at most 50%, and all other traffic should get what is left
over but only up to 50% of the bandwidth.
The three TC menus would be configured as follows:
15.1.1.1. TC Interfaces
Interface Inbound bandwidth Outbound bandwidth
eth1 5000kbit 5000kbit
15.1.1.2. TC Classes
Interface Mark Minimum Maximum Priority Options
eth1 1 full/2 full 0
eth1 2 1kbit full 1 tcp-ack
eth1 3 full/5 full*5/10 2
eth1 4 1kbit full*5/10 3 default