Foundation Summary

The Foundation Summary is a collection of information that provides a convenient review of many key concepts in this chapter. If you are already comfortable with the topics in this chapter, this summary can help you recall a few details. If you just read this chapter, this review should help solidify some key facts. If you are doing your final preparation before the exam, this information is a convenient way to review the day before the exam.

Table 14-7. Comparison of Router Redundancy Protocols

	HSRP	VRRP	GLBP
Standardized	No; Cisco-proprietary, RFC 2281	Yes; RFC 2338	No; Cisco-proprietary
Router roles	Active router, standby router	Master router, backup router	AVG, AVF
Load balancing	Only through multiple HSRP groups, different client gateways	Only through multiple VRRP groups, different client gateways	Inherent with one GLBP group; all clients use same gateway; several methods available
Interface tracking	Yes	No	Yes
Virtual router MAC address	0000.0c07.acxx	0000.5e00.01xx	Assigned by AVG

Table 14-8. HSRP Configuration Commands

Task	Command Syntax
Set the HSRP priority	standby group priority priority
Set the HSRP timers	standby group timers hello holdtime
Allow router pre-emption	standby group preempt [delay seconds]
Use group authentication	standby group authentication string
Adjust priority by tracking an interface	standby group track type mod/num decrementvalue
Assign the virtual router address	standby group ip ip-address [secondary]

Table 14-9. VRRP Configuration Commands

Task	Command Syntax
Assign a VRRP router priority (default 100)	vrrp group priority level
Alter the advertisement timer (default 1 second)	vrrp group timers advertise [msec] interval
Learn the advertisement interval from the master router	vrrp group timers learn
Disable pre-empting (default is to pre-empt)	no vrrp group preempt
Change the pre-empt delay (default 0 seconds)	vrrp group preempt [delay seconds]
Use authentication for advertisements	vrrp group authentication string
Assign a virtual IP address	vrrp group ip ip-address [secondary]

Table 14-10. GLBP Configuration Commands

Task	Command Syntax
Assign a GLBP priority	glbp group priority level
Allow GLBP pre-emption	glbp group preempt [delay minimum seconds]
Define an object to be tracked	track object-number interface type mod/num {line-protocol | ip routing}
Define the weighting thresholds	glbp group weighting maximum [lower lower] [upper upper]
Track an object	glbp group weighting track object-number [decrement value]
Choose the load-balancing method	glbp group load-balancing [round-robin | weighted | host-dependent]
Assign a virtual router address	glbp group ip [ip-address [secondary]]