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 14: High Availability 241
Selecting the Master VRRP Router
Each VRRP router is configured with a priority between 1–254. A bidding process determines
which VRRP router is or becomes the master—the VRRP router with the highest priority.
The master periodically sends advertisements to an IP multicast address. As long as the backups
receive these advertisements, they remain in the backup state. If a backup does not receive an
advertisement for three advertisement intervals, it initiates a bidding process to determine which
VRRP router has the highest priority and takes over as master.
If, at any time, a backup determines that it has higher priority than the current master does, it can
preempt the master and become the master itself, unless configured not to do so. In preemption, the
backup assumes the role of master and begins to send its own advertisements. The current master
sees that the backup has higher priority and will stop functioning as the master.
A backup router can stop receiving advertisements for one of two reasons—the master can be down,
or all communications links between the master and the backup can be down. If the master has
failed, it is clearly desirable for the backup (or one of the backups, if there is more than one) to
become the master.
Note – If the master is healthy but communication between the master and the backup has failed,
there will then be two masters within the virtual router. To prevent this from happening, configure
redundant links to be used between the switches that form a virtual router.