GLBP Overview and Options

GLBP Overview and Features

Gateway Load Balancing Protocol (GLBP) can be utilized to exchange HSRP in environments the place you wish to load steadiness between a number of nodes, as an alternative of getting an energetic/standby pair. With the intention to improve on the capabilities of Scorching Standby Router Protocol (HSRP), Cisco developed GLBP. GLBP gives computerized, first-hop gateway load balancing, which permits for extra environment friendly useful resource utilization and decreased administrative prices. It’s an extension of HSRP and specifies a protocol that dynamically assigns duty for a digital IP deal with and distributes a number of digital MAC addresses to members of a Gateway Load Balancing Protocol group. In campus networks, Layer three VLAN interfaces act because the gateway for the hosts. These Layer three VLAN interfaces from totally different switches are load balanced utilizing GLBP. Layer three interfaces from a number of switches type one GLBP group. Every group incorporates one distinctive digital IP deal with. Supervisor 720 can have a most of 1024 GLBP teams (group numbers Zero to 1023). Supervisor 2 helps just one GLBP group. A GLBP group can have a most of four members. It implies that GLBP can load steadiness as much as four gateways Gateway Load Balancing Protocol gives redundancy for IP networks, making certain that consumer site visitors instantly and transparently recovers from first hop router failures, whereas permitting packet load sharing between a gaggle of redundant routers. GLBP gives load balancing over a number of routers (gateways) utilizing a single digital IP deal with and a number of digital MAC addresses. Every host is configured with the identical digital IP deal with, and all routers within the digital router group take part in forwarding packets. GLBP members talk between one another by way of hey messages despatched each three seconds to the multicast deal with, Consumer Datagram Protocol (UDP) port 3222 (supply and vacation spot). Gateway Load Balancing Protocol works by making use of a single digital IP deal with, which is configured because the default gateway on the hosts. The totally different routers that assume the forwarding function use totally different digital MAC addresses for a similar digital IP deal with to which packets are forwarded by the hosts. There are two kinds of routers in a Gateway Load Balancing Protocol group which make redundancy and cargo balancing work. Energetic Digital Gateway (AVG): One digital gateway inside a GLBP group is elected because the energetic digital gateway, and is accountable for the operation of the protocol. This router has the very best precedence worth, or the very best IP deal with within the group, if there isn’t any highest precedence. The AVG solutions all ARP requests for the digital router deal with. Which MAC deal with it returns depends upon which load-balancing algorithm it’s configured to make use of. Energetic Digital Forwarder (AVF): One digital forwarder inside a GLBP group is elected as energetic digital forwarder for a specified digital MAC deal with, and is accountable for forwarding packets despatched to that MAC deal with. A number of energetic digital forwarders can exist for every GLBP group. GLBP options : A) Load Sharing: You possibly can configure GLBP in such a means that site visitors from LAN shoppers may be shared by a number of routers, thereby sharing the site visitors load extra equitably amongst obtainable routers. The load sharing obtainable are: Host-dependent: Specifies a load balancing technique based mostly on the MAC deal with of a bunch the place the identical forwarder is at all times used for a specific host whereas the variety of GLBP group members stays unchanged. Spherical-robin: Specifies a load balancing technique the place every digital forwarder in flip is included in deal with decision replies for the digital IP deal with. This technique is the default. Weighted: Specifies a load balancing technique that’s dependent. To specify the load-balancing technique utilized by the AVG of the Gateway Load Balancing Protocol, use the “glbp load-balancing[host-dependent | round-robin | weighted]” command in interface configuration mode. A number of Digital Routers: GLBP helps as much as 1024 digital routers on every bodily interface of a router, and as much as four digital forwarders per group. Preemption: The redundancy scheme of GLBP allows you to preempt an energetic digital gateway with the next precedence backup digital gateway that has turn into obtainable. Forwarder preemption works in the same means, besides that forwarder preemption makes use of weighting as an alternative of precedence and is enabled by default. To configure the gateway to take over as AVG for a Gateway Load Balancing Protocol group if it has greater precedence than the present AVG, use the “glbp preempt” command in interface configuration mode. To configure a router to take over as AVF for a Gateway Load Balancing Protocol group if it has greater precedence than the present AVF, use the “glbp forwarder preempt” command in interface configuration mode. Authentication: You need to use a easy textual content password authentication scheme between GLBP group members to detect configuration errors. A router inside a GLBP group with a special authentication string than different routers will likely be ignored by different group members. To configure an authentication string for the GLBP, use the “glbp group authentication text string” command in interface configuration mode. Monitoring: You possibly can monitor totally different interfaces to decrement the GLBP weighting by various quantities. To configure an interface to be tracked the place the GLBP weighting modifications based mostly on the state of the interface, use the “track object-number interface type number ip routing” command in international configuration mode. Through the use of the “glbp weighting track” and “track” instructions to configure parameters for an interface to be tracked. If an interface on a router goes down, the weighting for the router may be decreased by a specified worth. Reference from

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