Cisco How-To Tutorials The Gateway Load Balancing Protocol (GLBP) feature was integrated into Cisco IOS Software Release (15)T. There are two methods a LAN host can determine its default gateway or first-hop router. The first method uses a dynamic process such as a. GLBP is a Cisco proprietary protocol which was made available in . I’ve been following your two previous tutorials on HSRP and VRRP.

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The other router or routers become standby and take over if the active router fails. One end will send the encrypted key called hash, using MD5 to the other.

Gateway Load Balancing Protocol GLBP Tutorial

This section covers a simple example of how GLBP can be configured in a basic common topology. Tables 2 and 3 show the basic commands that are required to configure GLBP between the two devices shown in Figure 1. There are two methods a LAN host can determine its default gateway or first-hop router. The line-protocol parameter will track the protocol state tuotrial the configured interface.

This scheme of things is not very efficient as if you have redundant uplinks connected to the standby routers, all the additional bandwidth provided by these uplinks will not be used. GLBP preemption is disabled by default. This address if entered must be in the same subnet as the interface IP address primary or secondary.

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High Availability – VRRP, HSRP, GLBP – Free CCNA Study Guide

I hope that this article provided some insight into the configuration steps that are required to configure GLBP and get it up and running. Although we can partially configure load balancing via HSRP or VRRP using multiple groups but we have to assign different default gateways on the hosts. If the virtual router gutorial fails, the virtual hlbp backup configured with the highest priority will become the virtual router master. Enable GLBP authentication using the configured key chain and group number of 1.


If a key-chain is configured with the command above, follow these next few steps to create the key-chain.

Configure GLBP to use the tracked object to influence its weighting. Because of this, a number of different technologies have been developed to provide redundancy at every point tktorial the network.

GLBP (Gateway Load Balancing Protocol) |

The alternative to using a dynamic discovery protocol is to statically configure a default gateway on tutorila host. Other members of the group provide backup for the AVG if it goes down. The ip routing parameter will track the IP routing capability of an interface is it configured with an IP address and operational? Table 4 covers all the commands that are required to perform these steps. If preemption is disabled, the virtual router backup that is elected to become virtual router master remains the master until the original virtual router master comes back online and becomes master again.

Tutoial second router then becomes primary. These two versions of HSRP are not compatible with each other.

GLBP (Gateway Load Balancing Protocol)

The problem with HSRP really is that only one router is active at one time. The IP address of the virtual router glgp the same as that configured on the Ethernet interface of R1 The default VRRP priority is also though and we configured it manually just for the sake of demonstration.

The output of show vrrp on R2 below shows that it is a virtual router backup having priority You can configure the priority of each virtual router backup with a value of 1 through using vrrp priority command. If there are multiple routers acting as virtual gblp backup, the one with the highest priority becomes the virtual router master if the original virtual router master fails. If the IP address of the physical interface on a VRRP router is configured as the virtual IP address, this router will function as the virtual router master.

R1 config-keychain-key tutoroal test-string. We will cover these three protocols in upcoming sections of the chapter.


These include GLBP timers helloholdredirect and timeoutaltering the default load balancing behavior the default is round robinconfiguring GLBP authentication, and basic interface tracking. Create and enter into key chain — key configuration mode using a key number of 1.

A given host always uses the same router. Communication between R4 continues without disruption or change at the host side. Syslog Tutorial Access list Sim 1 Simulator. Well, the answer here is when the standby becomes the active it will send tutrial gratuitous ARP reply to flush the CAM tables of the switches and the ARP cache of the hosts. Traffic is balanced proportional to a configured weight.

The main disadvantage of HSRP and VRRP is that only one gateway is elected to be the active gateway and used to forward traffic whilst the rest are unused until the active one fails.

R2 config-if glbp 1 authentication key-chain testchain. The expectation of full-time glp has certainly gotten considerably higher over the last decade.

tutoriaal This section will first go over the configuration process steps and commands that are used to perform a basic GLBP configuration. And load balancing is achieved! For example, if there are two routers in a group and R1 has double the forwarding capacity of router B, the weighting value of router A should be configured to be double the amount of R2. If the router R1 becomes unavailable, the backup with higher priority, that is R2should assume the role of master.

Find out more or Futorial In. The virtual router is made up of a single router acting as virtual router master and multiple yutorial acting as virtual router backup. If one group fails, we must reconfigure the default gateways on the hosts, which results in extra administrative burden.