First-Hop Redundancy Protocols Flashcards
Which First Hop Redundancy Protocol (FHRP) is Cisco Proprietary?
Hot-Standby Router Protocol (HSRP)
Used for redundancy on a local subnet, where two or more routers reference a virtual router.
What terms are used for routers in HSRP?
One Active Router, one Standby Router
How many virtual IP addresses and MAC addresses are used in HSRP?
one virtual IP address
one virtual MAC address
How are routers selected in HSRP?
The active router is selected by the router that has the highest priority value. The standby router has the second highest priority value.
Routers must be in the same group to participate in election.
What terms are used for routers in Virtual Router Redundancy Protocol (VRRP)?
one Master Router, all other routers are Backup Routers
How can you provide load balancing in a HSRP environment?
By configuring multiple HSRP groups or by configuring Gateway Load Balancing Protocol (GLBP)
What happens in Gateway Load Balancing Protocol (GLBP)?
One Active Virtual Gateway (AVG) (and 1 Virtual IP) and up to FOUR (4) Active Virtual Forwarders (AVF) (and 4 Virtual MAC addresses)
AVG assigns a virtual MAC address to AVFs. When AVG receives ARP requests sent to GLBP virtual IP, AVG responds with different virtual MAC addresses.
How are routers selected in VRRP?
The router with the highest priority value is set as the master, all other routers are backups
What are VRRP virtual MAC addresses?
0000.5E00.01XX
XX = hexidecimal group number
Backup Designated Router (BDR)
The router elected as a backup for the Designated Router (DR), which can take over sending and receiving updates in the event that the DR fails.
Designated Router (DR)
In OSPF, the router elected to send out updates to other routers, and receive updates from other routers.
First Hop Redundancy Protocol
A network protocol designed to ensure the availability of the default gateway by providing a backup failover device that is transparent to network clients.
Hot Standby Router Protocol (HSRP) Hello
Periodic messages exchanged by the Active and Standby routers to learn the state of each device. By default, the hello interval for HSRP is 3 seconds.
HSRP Holdtime
The interval an HSRP Standby router uses to determine if the Active Router has gone offline. By default, HSRP uses a holdtime of 10 seconds. Cisco recommends the holdtime be configured at least three times the value of the hello interval.
VRRP Master Advertisement Interval
The time interval between advertisement packets sent from the Master Router to other VRRP routers in the same group. By default, the default interval is 1 second.
