GLBP Protocol
GLBP is the abbreviation for “Gateway Load Balancing Protocol”. GLBP is a digital gateway protocol just like HSRP and VRRP. Nevertheless, not like others, GLBP has functionality of utilizing a number of bodily gateways concurrently. In case of HSRP or VRRP, just one bodily gateway in a standby/redundancy group is accountable for packet forwarding, others stay inactive in standby/backup state. GLBP has somewhat completely different mechanism of site visitors forwarding.
It elects one AVG (Lively Digital Gateway) for every group. Different group members act as backup of AVG. That is monitored utilizing howdy and holdtime timers, that are 3 and 10 seconds by default. The elected AVG then assigns a digital MAC handle to every member of the worldwide load balancing protocol group, thus enabling AVFs (Lively Digital Forwarders). Every AVF assumes duty for forwarding packets despatched to its digital MAC handle.
By default, GLBP routers use the native multicast handle 224.0.0.102 to ship howdy packets to their friends each 3 seconds over UDP 3222 (supply and vacation spot).
Associated – HSRP vs VRRP vs GLBP
Load Balancing Strategies
There are a number of strategies for load balancing:
- Spherical-robin: the AVG will hand out the digital MAC handle of AVF1, then AVF2, AVF3 and will get again to AVF1 and so on.
- Host-dependent: A bunch will be capable to use the identical digital MAC handle of an AVF so long as it’s reachable.
- Weighted: In order for you some AVFs to ahead extra site visitors than others you possibly can assign them a distinct weight.
Key Factors of GLBP Protocol
Beneath key factors can summarizes GLBP protocol:
- GLBP permits all of the Gateways to ahead the site visitors concurrently and moreover act as backup for every toher.
- AVG redundancy is managed by GLBP precedence and AVF redundancy is applied utilizing AVF weight worth and two further timers.
- By default, GLBP routers use the native multicast handle 224.0.0.102 to ship howdy packets to their friends each 3 seconds over UDP 3222 (supply and vacation spot).
- Cisco applied IPv6 assist for GLBP in IOS launch 12.2(33).
- That is monitored utilizing howdy and holdtime timers, that are 3 and 10 seconds by default
- GLBP makes use of load balancing mechanisms like – Spherical robin, Hosts dependent and weighted.
- GLBP routers use the native multicast handle 224.0.0.102 to ship howdy packets operates on UDP port 3222
Instance state of affairs: GLBP Protocol
Beneath state of affairs is useful in understanding the idea of GLBP and its supporting phrases :
Routers R1 and R2 LAN Interfaces run GLBP (Group 1) as per beneath Configuration:
R1
R1(config)#interface FastEthernet0/1
R1(config-if)#ip handle 192.168.0.252 255.255.255.0
R1(config-if)#glbp 1 ip 192.168.0.254R1(config)#interface FastEthernet0/0
R1(config-if)#ip handle 192.168.12.1 255.255.255.0
R2
R2(config)interface FastEthernet0/1
R2(config-if)ip handle 192.168.0.253 255.255.255.0
R2(config-if)glbp 1 ip 192.168.0.254R2(config)interface FastEthernet0/0
R2(config-if)ip handle 192.168.12.2 255.255.255.0
The next is the output from “present glbp transient” which shows major and backup AVG Router together with particulars on Lively Digital forwarders:
R1#present glbp transient
Interface Grp Fwd Pri State Handle Lively router Standby router
Fa0/1 1 – 100 Lively 192.168.0.254 native 192.168.0.253
Fa0/1 1 1 – Lively 0007.b400.0101 native –
Fa0/1 1 2 – Hear 0007.b400.0102 192.168.0.253 –
R2#present glbp transient
Interface Grp Fwd Pri State Handle Lively router Standby router
Fa0/1 1 – 100 Standby 192.168.0.254 192.168.0.252 native
Fa0/1 1 1 – Hear 0007.b400.0101 192.168.0.252 –
Fa0/1 1 2 – Lively 0007.b400.0102 native –
As per above output, R1 turns into the AVG for group 1
If required, beneath instructions can be issued to indicate extra element on GLBP AVG and AVF particulars together with AVG precedence and AVF weights.
Now that units are configured and we at the moment are prepared to check the trail taken by PC1 and PC2. (Be aware PC-1 and PC-2 are Routers configured as Finish hosts for testing function.)
PC-1#traceroute 192.168.12.1Type escape sequence to abort.
Tracing the path to 192.168.12.11 192.168.0.253 36 msec 72 msec 68 msec
2 192.168.12.1 124 msec 88 msec 92 msec
PC-1 takes the trail through R2 , which is the AVF for site visitors from 192.168.0.1 in the direction of 192.168.12.1.
PC-2#traceroute 192.168.12.1Type escape sequence to abort.
Tracing the path to 192.168.12.11 192.168.0.252 92 msec 72 msec 60 msec
As proven above, PC-2 takes the trail through R1 , which is the AVF for site visitors from 192.168.0.2 in the direction of 192.168.12.1.
Therefore, the above output reveals that each the gateways ie R1 and R2 and are lively and concurrently ahead the site visitors primarily based on the choice taken by AVG lively Router.
GLBP Instructions
Beneath desk reveals generally used GLBP instructions to configure primary GLBP and to alter GLBP’s conduct:
Proceed Studying:
A number of HSRP (MHSRP): Load Sharing FHRP
Load Sharing vs Load Balancing
