Home » SWITCH 642-813 Q&As » Section 5 - High Availability » 642-813 Q&A – Implement High Availability (46-50)

642-813 Q&A – Implement High Availability (46-50)

Section 5 – Implement High Availability, given a network design and a set of requirements

QUESTION NO: 46
On a 3550 EMI switch, which three types of interfaces can be used to configure HSRP? (Select three)
A. Loopback interface
B. SVI interface
C. Routed port
D. Access port
E. EtherChannel port channel
F. BVI interface
Answer: BCE

Explanation:
This Hot Standby Router Protocol (HSRP) provides routing redundancy for routing IP traffic without being dependent on the availability of any single router. To use this feature, you must have the enhanced multilayer software image installed on your switch. All Catalyst 3550 Gigabit
Ethernet switches ship with the enhanced multilayer software image (EMI) installed. Catalyst 3550 Fast Ethernet switches can be shipped with either the standard multilayer software image (SMI) or EMI pre-installed. You can order the Enhanced Multilayer Software Image Upgrade kit to upgrade Catalyst 3550 Fast Ethernet switches from the SMI to the EMI.
Only routed interfaces that provide access to hosts can be configured for HSRP. These interfaces include: routed Ethernet, routed fast Ethernet, routed Gigabit Ethernet, SVI, and EtherChannel.

QUESTION NO: 47
Refer to the exhibit. Which Virtual Router Redundancy Protocol (VRRP) statement is true about the roles of the master virtual router and the backup virtual router?

46
A.Router A is the master virtual router, and Router B is the backup virtual router. When Router A fails, Router B will become the master virtual router. When Router A recovers, Router B will maintain the role of master virtual router.
B.Router A is the master virtual router, and Router B is the backup virtual router. When Router A fails, Router B will become the master virtual router. When Router A recovers, it will regain the master virtual router role.
C.Router B is the master virtual router, and Router A is the backup virtual router. When Router B fails, Router A will become the master virtual router. When Router B recovers, Router A will maintain the role of master virtual router.
D.Router B is the master virtual router, and Router A is the backup virtual router. When Router B fails, Router A will become the master virtual router. When Router B recovers, it will regain the master virtual router role.
Answer: B

QUESTION NO: 48
Refer to the exhibit. The Gateway Load Balancing Protocol has been configured on routers R1 and R2, and hosts A and B have been configured as shown. Which statement can be derived from the exhibit?

47
A.The GLBP weighted load balancing mode has been configured.
B.The GLBP host-dependent, load-balancing mode has been configured.
C.The GLBP round-robin, load-balancing mode has been configured.
D.The host A default gateway has been configured as 10.88.1.1/24.
E.The host A default gateway has been configured as 10.88.1.4/24.
F.The host A default gateway has been configured as 10.88.1.10/24.
Answer: F
Explanation:
To provide a virtual router, multiple switches (routers) are assigned to a common GLBP group.
Rather than having just one active router performing forwarding for the virtual router address, all routers in the group can participate and offer load balancing by forwarding a portion of the overall traffic.
The advantage is that none of the clients have to be pointed toward a specific gateway address they can all have the same default gateway set to the virtual router IP address. The load balancing is provided completely through the use of virtual router MAC addresses in ARP replies returned to the clients. As a client sends an ARP request looking for the virtual router address, GLBP sends back an ARP reply with the virtual MAC address of a selected router in the group. The result is that all clients use the same gateway address but have differing MAC addresses for it.

QUESTION NO: 49
Refer to the exhibit. Based on the debug standby output in the exhibit, which HSRP statement is true?

49
A. DSW111 is the active router because it is the only HRSP-enabled router on that segment.
B. DSW111 is the active router because the standby timer has been incorrectly configured.
C. DSW111 is the active router because it has a lower priority on that VLAN.
D. DSW111 is the active router because it has a lower IP address than the tying priority router on that VLAN.
E. DSW111 is the active router and is advertising the virtual IP address 10.10.10.111 on VLAN 11.
Answer: A
Explanation:
In the output shown, it can be seen that the standby router is unknown, and the active timer is expired meaning that this router was unable to locate any other HSRP enabled routers on the LAN. It then became the active router, with no standby router.

QUESTION NO: 50
Refer to the exhibit. GLBP has been configured on the network. When the interface serial0/0/1 on router R1 goes down, how is the traffic coming from Host1 handled?

50
A.The traffic coming from Host1 and Host2 is forwarded through router R2 with no disruption.
B.The traffic coming from Host2 is forwarded through router R2 with no disruption. Host1 sends an ARP request to resolve the MAC address for the new virtual gateway.
C.The traffic coming from both hosts is temporarily interrupted while the switchover to make R2 active occurs.
D.The traffic coming from Host2 is forwarded through router R2 with no disruption. The traffic from Host1 is dropped due to the disruption of the load balancing feature configured for the glbp group.
Answer: A
Explanation:
The Gateway Load Balancing Protocol (GLBP) is a Cisco-proprietary protocol designed to overcome the limitations of existing redundant router protocols. Some of the concepts are the same as with HSRP/VRRP, but the terminology is different and the behavior is much more dynamic and robust and allows for load balancing.
The trick behind this load balancing lies in the GLBP group. One router is elected the active virtual gateway (AVG). This router has the highest priority value, or the highest IP address in the group, if there is no highest priority. The AVG answers all ARP requests for the virtual router address.
Which MAC address it returns depends on which load-balancing algorithm it is configured to use.
In any event, the virtual MAC address supported by one of the routers in the group is returned.
According to exhibit, Company1 is the active virtual gateway and Company2 is the standby virtual gateway. So, when Company1 goes down, Company2 will become active virtual gateway and all data goes through Company2.