Home » Cisco » 300-115 » Which of the following is required to allow load balancing between three HSRP routers connected to the same LAN?
Which of the following is required to allow load balancing between three HSRP routers connected to the same LAN?
A. A single HSRP group with all three routers as active routers for the group
B. A single HSRP group with one active router for the group
C. Two HSRP groups, each with an active router
D. Two HSRP groups with one active router for both the groups
E. Three HSRP groups, each with an active router
F. Three HSRP groups with one active router for all groups
Correct Answer: E
Explanation/Reference:
Answer:
You should configure three HSRP groups on all three routers and select an active router for each of the groups. You can create up to 256 (0 to 255) groups. Each router should be the active router for one of the three groups and the standby router for the remaining two groups.
If you want to use HSRP on a Layer 3 switch, the switch ports must be one of the following:
EtherChannel port Refers to a Layer 3 switch port used for EtherChannel
Routed port Refers to a Layer 3 port on a switch used for routing and for inter-VLAN routing
Switch virtual interface (SVI) Refers to a Layer 2 switch port used for inter-VLAN routing
Routed ports are the physical Layer 3 interfaces that allow you to configure a switch as a router. The no switchport command allows the port to be used purely as a Layer 3 port. SVIs are Layer 3 logical interfaces of a switch that allow you to enable inter-VLAN routing on Layer 3 switches. An SVI is configured as a VLAN interface and has at least one physical interface assigned to the VLANs.
Creating a single HSRP group with all three routers as active routers for the group is incorrect. An HSRP group cannot have multiple active routers; it can have only one active router at a time.
Creating a single HSRP group with one active router for the group is incorrect because it does not allow load balancing between the three routers. All traffic will be passed through the active router.
Creating two HSRP groups with an active router each is incorrect because it only allows load balancing between two of the routers and not three of them.
Creating two HSRP groups with one active router for both groups, or three HSRP groups with one active router for all groups, is incorrect. Doing so does not enable load balancing on all three routers. Only the active router will be used for traffic forwarding.
Objective:
Infrastructure Services Sub-Objective:
Configure and verify first-hop redundancy protocols
References:
Internetworking Case Studies > Using HSRP for Fault-Tolerant IP Routing > Configuring Multiple Hot Standby Groups > Load Sharing
Catalyst 3750 Switch Software Configuration Guide, 12.2(40)SE > Configuring HSRP > Configuring HSRP > HSRP Configuration Guidelines Catalyst 3750 Switch Software Configuration Guide, 12.2(40)SE > Configuring HSRP > Configuring HSRP > Multiple HSRP
