Rate Limiting - ABB EDS500 Series Function Manual

Functions
CoS (Class-of-Service)
7
6
5
4
3
2
1
0
Table 11: Class-of-Service and queues
If any loss of data of the critical services should be avoided at high loads on the bandwidth
then the scheduling has to be set to strict i.e. the priority queuing has to be modified.
To set the connections for the network infrastructure (when using VLANs then these are the
trunk ports) where the IEEE 802.1p priority is considered these ports have to trust the CoS
tag (example: <set switch port1 trust cos>).
The default value for trust is: cos.
If instead incoming frames on a port should be assigned to a fixed CoS (when using VLANs
these are the access ports) then, on the one hand, the port CoS has to be configured
(example: <set switch port1 cos {0-7}>) and, on the other hand, the port has to configured in
such a way that possibly existing tags are not used to determine the priority but the set CoS
(example: <set switch port1 trust none>).
If QoS is to be used without VLANs then the IEEE 802.1p tag has to be activated explicitly for
that port (priority tagging). Otherwise the packets are forwarded without tag. (Example: <set
interface port1 encapsulation eth-dot1p>).
Commands to configure QoS
< s e t s w i t c h s c h e d u l i n g { . . . } >
< s e t s y s t e m c o s { . . . } >
< s e t s w i t c h { p o r t . . . } c o s { . . . } >
< s e t s w i t c h { p o r t . . . } t r u s t { . . . } >
< s e t s w i t c h { p o r t . . . } e n c a p s u l a t i o n { . . . } >
2.11

Rate Limiting

While QoS/IEEE 802.1p CoS takes care that frames can be prioritized at the place where
bandwidth overload happens, it is the task of the rate limiting to limit the incoming or
outgoing data rate at an interface in general. It can also be set which frame types should be
limited and can be used as broadcast storm control function.
1KGT151021 V000 1
Queue
0
1
2
3
Rate Limiting
Weighted-Fair priority
8
4
2
1
33