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Unified QoS - Locally Generated Packet Prioritization on Cisco 12000 Series Router, Integrated Services Engine (ISE) Line Cards

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Unified QoS-Locally Generated Packet Prioritization on Cisco 12000 Series Router, Integrated Services Engine Line Cards

Table Of Contents

Unified QoS-Locally Generated Packet Prioritization on Cisco 12000 Series Router, Integrated Services Engine Line Cards

Unified QoS-Locally Generated Packet Prioritization Feature Overview

Benefits

Restrictions

Related Features and Technologies

Related Documents

Supported Platforms

Supported Standards, MIBs, and RFCs

Prerequisites

Configuration Tasks

Command Reference

Glossary


Unified QoS-Locally Generated Packet Prioritization on Cisco 12000 Series Router, Integrated Services Engine Line Cards


Part Number OL-8687-01 (Rev. A0) November 16, 2007

Feature History

Release
Modification

12.0(32)S

This feature was introduced on the Cisco 12000 Series Router, Integrated Services Engine (ISE) line cards.


This feature module provides information on Unified QoS-Locally Generated Packet Prioritization in the following sections:

Unified QoS-Locally Generated Packet Prioritization Feature Overview

Supported Platforms

Supported Standards, MIBs, and RFCs

Prerequisites

Configuration Tasks

Command Reference

Glossary

Unified QoS-Locally Generated Packet Prioritization Feature Overview

The Unified QoS-Locally Generated Packet Prioritization feature on Integrated Services Engine (ISE) line cards brings the Route Processor Packet Prioritization scheme up-to-date and in conformance with the latest Route Processor Packet Prioritizing scheme implemented on the Cisco 12000 SIP-400 and Cisco 12000 SIP-600 Shared Port Adapters (SPAs).

With Unified QoS-Locally Generated Packet Prioritization provides the following feature updates:

Route processor packets with an IP precedence of 7 and an MPLS exp of 7 are treated as regular traffic and not as control plane packets. This gives customers more QoS configuration options.

Non-drop flag (VIP - very important packet) is set only for important route processor generated packets (not implemented on the 4-Port Gigabit Ethernet ISE Line Card).

Locally generated packets are primarily Layer 2 packets and other control packets that are time-sensitive for the router.

Table 1 shows a matrix of the locally generated packet prioritization scheme.

Table 1 Locally Generated Packet Prioritization Scheme

 
Important Packet
Set VIP = 1
Unimportant Packet
Set VIP = 0
Packet /
Configuration

PAK_PRIORITY (flag = 1)
(important packet)

No PAK_PRIORITY (flag=0)

non-IP
non-Tag

IP/Tag

Important

Uninimportant

All prec values

prec 6

prec != 6

no MQC

LLQ

LLQ

LLQ

Default Q

MQC
with priority class
(LLQ is used)

prec6Q
defQ

prec6Q
defQ

matchedQ
Default Q

matchedQ
Default Q

MQC
without priority class

prec6Q
LLQ

prec6Q
LLQ

matchedQ
LLQ

matchedQ
Default Q


The matchedQ priority flag indicates that packets are sent to the queue associated with the first matched class for the packet. ACL or any other class may be matched as well. If the first matched class does not have a queue, egress packets are sent to the Default Q or the low latency queue (LLQ).

The PAK_PRIORITY flag is set by the protocol code for prioritization on the egress card and exists in the packet until the packet is transmitted by the egress card.

IP packets may have prec = 6 set. For the Layer 2 packets, this is a flag.

The following types of control packets are flagged with PAK_PRIORITY and receive higher priority than other packets:

HDLC keepalives

FR LMI packets

HDLC Station

PPP Station

FR ISIS

CLNS

PPP control packets

ATM OAM

IP bad TTL

IP and MPLS that need fragmentation

IPv6 control traffic

MLD report, ICMPv6 type is 131

ARP

IGRP hello

FR keepalive (LMI)

L2TP control packets

BFD messages

Benefits

Unified QoS-Locally Generated Packet Prioritization provides customers with the following benefits:

More QoS configuration options

Consistent behavior of all Integrated Services Engine (ISE) line cards

Prioritization by configured MQC policy

Restrictions

The following restrictions apply to the ISE ATM line cards:

VIP packets sent to the slow path queue may cause additional latency.

If no policy is configured, all low latency queue (LLQ) packets are sent to the default queue.

Queues are subject to one of 2 admission policies: Queue Limit or Weighted Random Early Detection (WRED).

OAM packets from Cisco IOS Release 12.0(30)S are processed by the line card CPU as distributed OAM (dOAM). Distributed OAM (dOAM) is the default. For distributed OAM (dOAM), all important packets are sent to the low latency queue (LLQ) if it is present, otherwise they are sent to the default queue. The prec6 queue is used by the route processor only if distributed OAM (dOAM) is disabled.

The following restrictions apply to the ISE channelized line cards:

PPP/MLPPP control packets use a special queue for port 1022.

When the queue for prec6 is not present, important non-control packets use a special queue for port 1022

The following restrictions apply to the 4-Port OC-12 line card:

The high and low ports for the three physical egress ports use the same queues and are defined by the MQC policy. The high and low ports are used for:

control data for DPT L2 packets

high priority packets for customer traffic and control plane traffic
(the total bandwidth should not be more than 25% of the total port bandwidth)

low (normal) priority traffic

Egress packets that have a precedence that is higher than the configured threshold or that are classified as important are sent through the high priority port.

Related Features and Technologies

Cisco IOS Quality of Service (QoS) Solutions for Cisco 12000 Series Routers

Related Documents

Refer to the following documents for information on configuring multicast traffic.

Cisco 12000 Series Router Configuration Guide for Cisco IOS Release 12.0S

Also refer to the Installation and Configuration Guide for a specific Cisco 12000 Series Router.

Supported Platforms

The Unified QoS-Locally Generated Packet Prioritization feature is supported on the following Cisco 12000 Series Router, Integrated Services Engine (ISE) line cards running Cisco IOS Release 12.0(32)S:

POS line cards

1-port OC48c/STM16c POS

1-port CHOC48/STM16>OC12/STM4>OC3/STM1>DS3/E3

4-port OC12c/STM16c POS

4-port CHOC12/STM4>OC3/STM1>DS3/E3

16-port OC3c/STM1c POS

4-port OC3c/STM1c POS

8-port OC3c/STM1c POS

Ethernet line cards

4-port Gigabit Ethernet ISE Line Card

ATM line cards

4-port OC12/STM4 ATM LC

8-port OC3/STM1 ATM LC

4-port OC-3/STM-1 ATM LC

Channelized line cards

1-port OC12 DS1

DPT line cards

4-port OC-12

2-port OC-12

POS SPAs

1-port OC-192c/STM-64 POS SPA

2-port OC48-POS/RPR SPA SPA

Serial SPAs

2-port T3/E3 Serial SPA

4-port T3/E3 Serial SPA

Channelized SPAs

2-port Channelized T3 to DS0 SPA

4-port Channelized T3 to DS0 SPA

Ethernet SPAs

8-port Fast Ethernet SPA

1-port 10-Gigabit Ethernet SPA

5-port 10 Gigabit Ethernet SPA

10-port Gigabit Ethernet SPA

Supported Standards, MIBs, and RFCs

Standards

No new or modified standards are supported, and support for existing standards has not been modified.

MIBs

No new or modified MIBs are supported, and support for existing MIBs has not been modified.

RFCs

No new or modified RFCs are supported, and support for existing RFCs has not been modified.

Prerequisites

No prerequisites are required for this feature.

Configuration Tasks

No configurations are required for this feature.

Command Reference

No new or modified CLI commands were introduced for the Unified QoS-Locally Generated Packet Prioritization feature in Cisco IOS Release 12.0(32)S.

Glossary

ISE

Integrated Services Engine

LLQ

Low latency queue

QoS

Quality Of Service. Measure of performance for a transmission system that reflects its transmission quality and service availability.

RED

Random Early Detection

SPA

Shared port adapter. A SPA is a modular, platform-independent port adapter that inserts into a subslot of a compatible SIP carrier card to provide network connectivity and increased interface port density. The SPA provides the interface between the network and the SIP.

WRED

Weighted Random Early Detection. Queueing method that ensures that high-precedence traffic has lower loss rates than other traffic during times of congestion.