Overview - Alcatel-Lucent 7210 SAS-R6 OS Quality Of Service Manual

Overview

Overview
The network QoS policy consists of an ingress and egress component. There are two types of
network QoS policies, network QoS policy of type port and network QoS policy of type ip-
interface. A port network policy is applied to network and hybrid ports, used for classification/
remarking of IP traffic using DSCP or Dot1p values. Either DSCP or Dot1p can be used for
ingress classification but not both. Both DSCP and Dot1p can be configured at egress for
remarking. The ip-interface type network policy is applied to IP Interface, used for classification/
remarking of MPLS traffic using EXP values. Note that the FC to Dot1p marking values
configured on the port, is also used to mark the Dot1p in the VLAN tag, if any, used for MPLS
traffic.
The ingress component of the policy defines how EXP, DSCP or Dot1p bits are mapped to internal
forwarding class and profile state. The forwarding class and profile state define the Per Hop
Behavior (PHB) or the QoS treatment through the 7210 SAS . From release 4.0, the profile
mapping is defined using a new policy mpls-lsp-exp-profile-map. The mpls-lsp-exp-profile-map
defines the mapping between the LSP EXP bits and the profile (in or out) to be associated with a
packet. The mapping on each ip-interface or port defaults to the mappings defined in the default
network QoS policy until an explicit policy is defined for the IP interface or port. It also defines
the rate-limiting parameters for the traffic mapped to each forwarding classes. Traffic mapped to
each forwarding class can be rate limited using separate meters for each unicast and multipoint
traffic (multipoint is used for IP Interface for MPLS traffic and for IP multicast traffic received on
network or hybrid port).
The total number of QoS resources available for network IP interfaces are 512 entries and 256
meters. The software allocates these resources to an IP interface on a first-come first-served
basis.The number of IP interfaces that can be successfully configured, varies based on the number
of meters and entries utilised per IP interface. Irrespective of the QoS resource allocation, the
system enforces the limit of maximum number of IP interfaces to 64.
The total number of QoS resources, that is ingress classification entries and policers, available for
use with IP interfaces is limited. The software allocates these resources to an IP interface on a first
come first serve basis. The number of resources used per IP interface limits the total number of IP
interfaces configured on the system (the total number of IP interfaces allowed is also subject to a
system limit).
The egress component of the network QoS policy defines the LSP EXP, DSCP or Dot1p bits
marking values associated with each forwarding class.
By default, network qos policy remarking is always disabled. If the egressing packet originated on
an ingress SAP, the egress EXP bit marking based on the forwarding class and the profile state.
The default map of FC-EXP marking is as shown in default network qos policy, policy id 2. All
non-default network qos policies inherits the FC-EXP map.
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