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
148 Chapter 8: Quality of Service BMD00113, September 2009
Using DSCP Values to Provide QoS
The six most significant bits in the TOS byte of the IP header are defined as DiffServ Code Points
(DSCP). Packets are marked with a certain value depending on the type of treatment the packet
must receive in the network device. DSCP is a measure of the Quality of Service (QoS) level of the
packet.
Differentiated Services Concepts
To differentiate between traffic flows, packets can be classified by their DSCP value. The
Differentiated Services (DS) field in the IP header is an octet, and the first six bits, called the DS
Code Point (DSCP), can provide QoS functions. Each packet carries its own QoS state in the DSCP.
There are 64 possible DSCP values (0-63).
Figure 15 Layer 3 IPv4 Packet
The GbE2c can perform the following actions to the DSCP:
Read the DSCP value of ingress packets
Re-mark the DSCP value to a new value
Map the DSCP value to an 802.1p priority
Once the DSCP value is marked, the GbE2c can use it to direct traffic prioritization.
7 6 5 4 3 2 1 0
Differentiated Services Code Point (DSCP)
unused
Version
Length
ToS
Length
ID
Offset TTL
Proto
FCS
DIP
SIP
Data