Netgear XCM8810 Chassis User Manual - Page 366

Introduction to Rate Limiting, Rate Shaping, and Scheduling, Single-Rate QoS

Page 366 highlights

NETGEAR 8800 User Manual one traffic group based on the precedence defined for the switch platform. In general, the more specific traffic group definition takes precedence. Table 43 shows the traffic group precedence for the supported switch platforms (number 1 is the highest precedence). Table 43. Traffic Group Precedence NETGEAR 8800 Switches 1. ACL-based traffic groups for IP packets (specifies IP address information) 2. ACL-based traffic groups for Ethernet frames (specifies MAC address information) 3. CoS 802.1p-based traffic groups 4. Port-based traffic groups 5. VLAN-based traffic groups 6. DiffServ-based traffic groups Introduction to Rate Limiting, Rate Shaping, and Scheduling The rate limiting and rate shaping terms are used throughout this chapter to describe QoS features. Some QoS features perform both rate limiting and rate shaping. Rate limiting is the process of restricting traffic to a peak rate (PR). Rate shaping is the process of reshaping traffic throughput to give preference to higher priority traffic or to buffer traffic until forwarding resources become available. Both rate limiting and rate shaping allow you to take action on traffic that exceeds the configured limits. These actions include forwarding traffic, dropping traffic, and marking the excess traffic for possible drops later in the communication path. Software counters allow you to record traffic statistics such as total packets forwarded and total packets dropped. The following sections provide general information on rate-limiting and rate-shaping support in the XCM8800 software: • Single-Rate QoS on page 366 • Dual-rate QoS on page 367 • Rate Specification Options on page 367 • Disabling Rate Limiting and Rate Shaping on page 368 • Scheduling on page 368 Single-Rate QoS Single-rate QoS defines a single rate for traffic that is subject to QoS. Single-rate QoS is the most basic form of rate limiting and is well suited for constant rate traffic flows such as video or where more complex dual-rate QoS is not needed. The traffic that meets the rate requirement is considered in-profile. Traffic that does not meet the specified rate is considered out-of-profile. A two-color system is often used to describe or mark the single-rate QoS result. In-profile traffic is marked green, and out-of-profile traffic is marked red. 366 | Chapter 15. QoS

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366
|
Chapter 15.
QoS
NETGEAR 8800 User Manual
one traffic group based on the precedence defined for the switch platform. In general, the
more specific traffic group definition takes precedence.
Table 43
shows the traffic group
precedence for the supported switch platforms (number 1 is the highest precedence).
Introduction to Rate Limiting, Rate Shaping, and Scheduling
The rate limiting and rate shaping terms are used throughout this chapter to describe QoS
features. Some QoS features perform both rate limiting and rate shaping. Rate limiting is the
process of restricting traffic to a peak rate (PR). Rate shaping is the process of reshaping
traffic throughput to give preference to higher priority traffic or to buffer traffic until forwarding
resources become available.
Both rate limiting and rate shaping allow you to take action on traffic that exceeds the
configured limits. These actions include forwarding traffic, dropping traffic, and marking the
excess traffic for possible drops later in the communication path. Software counters allow you
to record traffic statistics such as total packets forwarded and total packets dropped.
The following sections provide general information on rate-limiting and rate-shaping support
in the XCM8800 software:
Single-Rate QoS
on page 366
Dual-rate QoS
on page 367
Rate Specification Options
on page 367
Disabling Rate Limiting and Rate Shaping
on page 368
Scheduling
on page 368
Single-Rate QoS
Single-rate QoS defines a single rate for traffic that is subject to QoS. Single-rate QoS is the
most basic form of rate limiting and is well suited for constant rate traffic flows such as video
or where more complex dual-rate QoS is not needed. The traffic that meets the rate
requirement is considered
in-profile
. Traffic that does not meet the specified rate is
considered
out-of-profile
. A two-color system is often used to describe or
mark
the single-rate
QoS result. In-profile traffic is marked green, and out-of-profile traffic is marked red.
Table 43.
Traffic Group Precedence
NETGEAR 8800 Switches
1.
ACL-based traffic groups for IP packets (specifies IP address information)
2.
ACL-based traffic groups for Ethernet frames (specifies MAC address information)
3.
CoS 802.1p-based traffic groups
4.
Port-based traffic groups
5.
VLAN-based traffic groups
6.
DiffServ-based traffic groups