BLADE OS™ Application Guide HP GbE2c Ethernet Blade Switch for c-Class BladeSystem Version 5.1 Advanced Functionality Software
Table Of Contents
- Contents
- Figures
- Tables
- Preface
- Part 1: Basic Switching
- Accessing the Switch
- The Management Network
- Local Management Using the Console Port
- The Command Line Interface
- Remote Management Access
- Client IP Address Agents
- Securing Access to the Switch
- Setting Allowable Source IP Address Ranges
- RADIUS Authentication and Authorization
- TACACS+ Authentication
- LDAP Authentication and Authorization
- Secure Shell and Secure Copy
- Configuring SSH/SCP Features on the Switch
- Configuring the SCP Administrator Password
- Using SSH and SCP Client Commands
- SSH and SCP Encryption of Management Messages
- Generating RSA Host and Server Keys for SSH Access
- SSH/SCP Integration with Radius Authentication
- SSH/SCP Integration with TACACS+ Authentication
- End User Access Control
- Ports and Trunking
- Port-Based Network Access Control
- VLANs
- Spanning Tree Protocol
- RSTP and MSTP
- Link Layer Discovery Protocol
- Quality of Service
- Accessing the Switch
- Part 2: IP Routing
- Basic IP Routing
- Routing Information Protocol
- IGMP
- OSPF
- OSPF Overview
- OSPF Implementation in BLADE OS
- OSPF Configuration Examples
- Remote Monitoring
- Part 3: High Availability Fundamentals
- High Availability
- Layer 2 Failover
- Server Link Failure Detection
- VRRP Overview
- Failover Methods
- BLADE OS Extensions to VRRP
- Virtual Router Deployment Considerations
- High Availability Configurations
- High Availability
- Part 4: Appendices
- Index
BLADE OS 5.1 Application Guide
BMD00113, September 2009 Chapter 8: Quality of Service 151
Using 802.1p Priorities to Provide QoS
802.1p Overview
BLADE OS provides Quality of Service functions based on the priority bits in a packet’s VLAN
header. (The priority bits are defined by the 802.1p standard within the IEEE 802.1q VLAN
header.) The 802.1p bits, if present in the packet, specify the priority that should be given to packets
during forwarding. Packets with a numerically higher (non-zero) priority are given forwarding
preference over packets with lower priority bit value.
Packets with a priority mapped to a higher Class of Service (COS) and COS queue (COSq) weight
are given forwarding preference over packets with priority mapped to a lower COS and COSq
weight. The scheduling scheme is Weight Round Robin (WRR), with user-configurable weight
from 0 to 15 for a COSq. The GbE2c can have two output Class of Service queues (COSq).
The IEEE 802.1p standard uses eight levels of priority (0-7). Priority 7 is assigned to highest
priority network traffic, such as OSPF or RIP routing table updates, priorities 5-6 are assigned to
delay-sensitive applications such as voice and video, and lower priorities are assigned to standard
applications. A value of 0 (zero) indicates a “best effort” traffic prioritization, and this is the default
when traffic priority has not been configured on your network. The GbE2c can filter packets based
on the 802.1p values, and it can assign or overwrite the 802.1p value in the packet.
Figure 16 Layer 2 802.1q/802.1p VLAN Tagged Packet
Ingress packets receive a priority value, as follows:
Tagged packets—The GbE2c reads the 802.1p priority in the VLAN tag.
Untagged packets—The GbE2c tags the packet and assigns an 802.1p priority, based on the
port’s default priority (/cfg/port <x>/8021ppri).
Egress packets are placed in a COS queue based on the priority value, and scheduled for
transmission based on the scheduling weight of the COS queue.
7 6 5 4 3 2 1 0
Priority
7 6 5 4 3 2 1 0
VLAN Identifier (VID)
SFD
DMAC
SMAC Tag
E Type
Data
FCS
Preamble