Negative points of its two protocols:
– By default, only one router is used as a "exit door"
– It is however possible to do load-balancing by creating several working groups.-
– The balancing of customers is therefore done manually.
CISCO to create the GLBP protocol to make dynamic customer load balancing! Awesome, isn't it?
– CISCO Owner
– Group number – 0 to 1023
– Priority – 1 to 255 (defect – 100)
Active Virtual Gateway (AVG)
In a GLBP group, a router will be elected AVG.
The AVG router (Active for HSRP / Master for VRRP) is going to be the one that:
– Has the highest priority
In the event of a tie, the router with the highest IP address will assume this role.
The GLBP protocol works as a group
– No limit on the number of members per GLBP group
– Each GLBP group can have up to 4 virtual MAC addresses
The AVG router:
– Distributes the role AVG Secondary
– Distributes AVF roles
– Generates and distributes virtual MAC addresses (4 Max)
– Responds to CUSTOMER-generated ARP queries.
Active Virtual Forwarder (AVF)
All routers in the GLBP group can become AVF.
The chosen AVG router that will be AVF and assigns it a virtual MAC address.
This Mac address is in the form of:
The AVG router sends Hello packages to other routers, it also receives packages from them.
A Hello package lets other routers let us know it's working.
– Hellotime by default – 3s
Changing its timers can only be done on the AVG router, other routers will automatically learn these configurations.
The AVG router expects to receive hello packages from other members of the GLBP group.
Other members of the GLBP group expect to receive a hello package from the AVG router.
This waiting time corresponds to the "Holdtime"
- Holdtime default – 10s
If this waiting time is exceeded, the sender is considered "dead."
To change hello and Holdtime timers, use the following command:
Switch (config-if) glbp 1 timers msec 3000 10000
Hellotime – 1 to 60s or 50 to 60,000 miliseconds (msec)
Holdtime – Hellotime – max 180s
If a router is considered "Dead" the AVG router continues to send the virtual MAC address of that router
for a while.
This time frame is the "redirect time"
– Default Redirect Time – 600s
If the router in question does not return online, this virtual MAC address will no longer be distributed.
If an AVF router is considered "Dead," another AVF will support the MAC address of the "dead" router.
He's going to keep this MAC address for a while.
This time corresponds to the "Secondary Holdtime"
Secondary Holdtime by default – 14400s
To change the "Redirect timers" and "Secondary Holdtime" timers, use the following command:
Switch (config-if) glbp 1 timers redirect 600 14400
Redirect – 0 to 3600 seconds
Timeout – 700 to 64,800 seconds
The AVG router is responsible for the load distribution.
To do this, there are three methods:
– Round robin (default)
To change the way it works, use the following command:
Switch (config-if) glbp 1 load-balancing [ round-robin | weighted | host-dependent ]
Round robin (Default Method)
This method distributes virtual MAC addresses in order.
Load balancing is done equitably
The load balancing is based on the weight configured on each router.
Each customer will always come out by the same router.
Activation of GLBP
Switch (config-if) glbp 1 ip 192.168.10.254
Hoping this article has been helpful to you! Don't hesitate to let me know!!
This site has other network items, take the opportunity to browse the menu bar!