Specifications

Alcatel-Lucent
OS-LS6200 Series Page 29
remaining for shaping the traffic from each of the port traffic class queues. The egress rate shapers are
implemented using the Token bucket algorithm.
Traffic shaping can be set only per port of the LAG (Link Aggregated) members.
Regarding the rate-limit and traffic-shape commands under the interface command mode, here are the
valid value ranges:
1) rate-limit command is used to limits the rate of the incoming traffic and need to be configured
on an interface;
range: 62K – 1000M on GE and 62K – 100M on FE
2) traffic-shape command is used to configure the shaper of the egress queue on a port;
CIR range: 64K – 1000M on GE and 64K – 100M on FE; CBS range: 4096 – 16769020 bytes on GE.
QoS Marking 802.1p, TOS, DSCP marking
QoS Mapping QoS mapping: 802.1p to TOS/DSCP, TOS to 802.1p/DSCP, DSCP to 802.1p/TOS
Classification Classification per port, 802.1p (COS) value, MAC SA/DA, Ethertype, TOS precedence, DSCP value,
ICMP code and type, IP SA/DA, IP protocol, TCP/UDP port
Basic and Advanced QoS mode overview
In basic QoS mode, it is possible to activate a trust
mode. In addition, a single access control list can be
attached to one or more interfaces.
Quality of Service Advanced Mode
Advanced Quality of Service mode specifies flow
classification and assigns rule actions that relate to
bandwidth management. These rules are grouped into
a policy, which can be applied to an interface.
While the system facilities providing Access Control and CoS/QoS are given, there are several ways to
configure the system to provide the desired effect. These modes present different levels of
functionality and complexity to the user.
Note These Modes are different ways to control and configure the system CoS/QoS facilities, and not
different operational modes of the actual system CoS/QoS facilities.
There are three CoS/QoS control modes
• None
• Basic Mode
In Basic CoS mode the user can classify frames into broad classes, by the ingress interface
or by the value of a single frame header field. Each class can be directed to a desired egress
queue, and the user can also configure the queue servicing parameters. This is enough to
provide relative class-by-class differential services.
This mode does NOT include the facility to classify traffic into fine-grained flows (e.g.
define a flow as a specific value in a frame-header fields, or a combination of values in
several header fields) and does not include traffic measurement facilities.
• Advanced Mode
In Advanced mode CoS/QoS the user has access, and must explicitly configure all aspects
of all CoS/QoS facilities in use. Traffic may be classified into broad classes or fine-grained
flows.
Class of Service 802.1p Support The IEEE 802.1p signaling technique is an OSI Layer 2 standard for marking and prioritizing network
traffic at the data link/MAC sub-layer. 802.1p traffic is classified and sent to the destination. No
bandwidth reservations or limits are established or enforced. 802.1p is a spin-off of the 802.1Q
(VLANs) standard. 802.1p establishes eight levels of priority, similar to the IP Precedence IP Header
bit-field.
QoS Basic Mode
In basic QoS mode, it is possible to activate a trust
mode (to trust VPT, DSCP or none). In addition, a
single access control list can be attached to one or
more interfaces.
In the basic mode the user is actually “trusting” a specific domain in the network. Within that domain,
packets are marked on predefined fields (from L2 or L3) to signal the type of service they should get.
Nodes within the domain use these fields to assign the packet to a specific output queue. The initial
packet classification and marking of those fields was done in the ingress of the trusted domain.
Classification for basic mode
The user can select the trust behavior, i.e., identify the fields upon which the output service assignment
is done.
The following selections are available:
• VLAN tag (802.1p tag) / 802.1p port based
• DSCP
Only one selection can be applied at a time. The selection is done on a system basis, i.e., the selection
is applicable to all ports. User can also choose to trust none of the above, by that classifying all the
traffic to Best Effort service.
802.1p Tag-based
In this mode the IEEE802.1p tag is used to classify the packet. Packets with an IEEE802.1p tag are
mapped according to their VPT to one of the output queues. There is a default mapping of the VPT to
output queue as defined in the 802.1p standard.
802.1p Port-based
The IEEE 802.1p specifies a method for indicating frame priority based on the new fields defined in
the 802.1Q (VLAN) standard. The capabilities defined in 802.1Q include the definition of a VLAN
frame format, which allows carrying of VLAN identification and priority information over LAN
technologies. The IEEE 802.1p specifies a mechanism for indicating frame priority based on existing
priority fields - in the 802.1Q VLAN standard. 802.1p supports up to 8 traffic classes (priorities), with
multiple priority queues established on a per port basis.
L3 predefined fields
In this mode, the user configures the system to use the IP DSCP of the incoming packet to map the
packet to the output priority queues. The original VPT of the packet will be kept.
The mapping of the IP DSCP to priority queue is set on a per system basis. It can be enabled or
disabled per port. If this mode is active then a non-IP packet will always be classified to the best effort
queue.
Services for basic mode
Scheduling: Strict Priority (SP), and Weighted Round Robin (WRR)
The OmniStack LS 6200 su
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