200-301 torrent

200-301 torrent.10.1.1.0/24 Activated Subnet 1Alternate subnet 2VLAN 2 Subnet 10.1.2.0/24 Figure 6-7 HSRP Load Balancing Using Different Activation Routers in Each SubnetConcepts of GLBPBefore introducing the Gateway Load Balancing Protocol (GLBP), we have introduced HSRP and VRRP, which balance the packet load in each subnet, as shown in Figure 6-7. However, because traffic can vary from subnet to subnet and be difficult to predict, Cisco wanted a better FHRP option that went beyond just HSRP and VRRP load balancing per subnet. To address this need, Cisco introduced GLBP.By applying the activation/activation model in the subnet, GLBP is able to balance the packet load of each host. Each GLBP router in the subnet is able to receive packets sent by certain hosts outside the subnet. Each host remains ignorant of the FHRP, leaving the hosts with the same default gateway/router setting values and making no changes to the hosts when the router fails.GLBP creates a world that looks a lot like HSRP at first glance, but it makes some adjustments that allow GLBP to balance traffic. Similar to HSRP, all routers are configured with a virtual IP address, which is the IP address that all hosts use as their default router. The difference between GLBP and HSRP is in the MAC address and ARP process it uses, because GLBP actually uses ARPReply messages to balance traffic from different hosts and different routers.With GLBP, routers can play a special role called Active Virtual Gateway (AVG). the AVG replies to ARP requests for all virtual IP addresses. Each router has a unique virtual MAC address, so the AVG can use one virtual MAC to reply to some ARPRequests, and another to reply to others. The result is that some hosts on the subnet send data frames to the Ethernet MAC address of one of the routers, while others send their data frames to the MAC address of the second router.As an example, Figure 6-8 shows a process. In this process, GLBP balances the load on host A based on the Address Resolution Protocol (ARP) Reply issued by the AVG (R1). The figure uses the same IP address as the HSRP example in Figures 6-5 and 6-6 earlier. Both routers support the virtual IP address 10.1.1.1, and the host uses this address as the default router setting.The figure shows three messages from top to bottom that have the following activities.