User's Manual

42 ALFOplus 24GHz (North America) - Release 01.05.0x - MN.00395.E - 004
Tab.10 - Logical functions
7.3.1 Rate limiting
In SIAE equipment it is possible to apply the Rate Limit, i.e. to limit the total rate passing through an in-
terface. It is possible to apply the rate limiting from 64 kbit/s up to the maximum port speed (up to 1GE).
The values that can be inserted are pre-fixed from 64 kbit up to 10Mbit (64Kb, 128kb, 256kb, 512kb, 1Mb,
2Mb, 3Mb, 4Mb, 5Mb, 6Mb, 7Mb, 8Mb and 9Mb), In the range from 100Mbit/s up to 1Gbit/s the limiting
values can be chosen by the user with a 10Mbit/s step. i.e. the minimum selectable granularity is 10Mb/s.
7.3.2 Enhanced QoS Management
The SIAE switch scheduler provides enhanced QoS management features. Based on the ingress port (and
optionally also as a function of the VLAN-ID), there are four different modes that can be used to set the
priority of an Ethernet frame:
• Ethernet: the priority is set based on the PCP (Priority Code Point) field of the VLAN tag
(IEEE802.1p) (Native 802.1p C_Vid)
• MPLS: the priority is set based on the EXP (Experimental Bit) field of the MPLS tag (Native MPLS)
Logical function Description of included functionalities Examples
Physical Layer
management
Management of the phy parameters and charac-
teristics if the physical interfaces.
Ingress Filtering
Filter/drop frames on the base of specified crite-
ria and rules, ingress port rate limiting, storm
control.
Service Instance Mapping
Defines the association rules between an ingress
frame and its VLAN/EVC
All the frames with C-VID =
10 ore mapped to the
EVC-2
Classification
An Internal-Priority is assigned to the packed on
the base of selected criteria.
All the packets ingressing
port 1 have the highest
priority
Metering & Policing
It measures the service parameters such as oc-
cupied bandwidth, rate, etc....
CIR, EIR....definition
Ingress Manipulation &
Marking
Modified the packet format: add/remove/pre-
serve tags or modify the value of same fields
Forwarding
Determine the port/ports the packet shall egress
to.
On the base of DA-MAC, or
on the base of VID value.
Queue & Congestion
avoidance
Before egressing each packet is assigned to a
specific buffer selected in a set of N queues. Each
queue has a different priority. Specific rules are
used to determine if a packet can be added or
can be dropped.
Scheduling
The method adopted to empty the queues in or-
der to fulfill the available bandwidth
Example: WFQ algorithm
Shaping
The method adopted to shape the egressing
packets.
Egress Manipulation
Nodified the packet format: add/remove/pre-
serve tags or modify the value of some fields be-
fore egressing