RSSAll Entries in the "HSRP/VRRP/GLBP" Category

Understand HSRP States and HSRP State Transitions

HSRP States  In HSRP process, Router will go through the below states and finally Router will stay in Active or Standby or Listen state. An HSRP router can be in one of six different states. • Initial • Learn • Listen • Speak  • Standby • Active  Initial State This is first and starting state, The initial state indicates that HSRP does not run. This state is entered via a configuration change or when an interface first comes up. Learn State The router is neither in the active or standby state, nor does it have enough information to attempt to claim the active or standby role. Listen State The router knows the virtual IP address of HSRP group, but the router is neither the active router nor the standby router. It listens for hello messages from those routers. Speak State The router sends periodic hello messages and actively participates in […]

What is the difference between HSRP preempt and VRRP preempt

To decide an Active/Master Router, We have to enable preempt, configure priorities and Configure highest IP address on the Routers in the HSRP or VRRP group. In case of VRRP, Router which owns the IP address for the VRRP group is always becomes a Master Router. I thought the only the difference between HSRP and VRRP in case of preempt is Preempt ON by default in VRRP. The Router which is configured with the maximum configurable priority value of 254 in VRRP, that Router would become the master Router. This is not always true. There are some of the rules influence the Master and Preempt in VRRP, Find the difference between HSRP and VRRP in case preempt and Active/Master Router. Difference between HSRP Preempt and VRRP Preempt a)   In VRRP preempt enabled by default, In HSRP Preempt disabled by default. b)   In VRRP, In case priority is equal between Routers, […]

Understand and Configure HSRP Timers on Cisco Router

In below post you can understand the HSRP timers and HSRP timers configuration steps on Cisco Router or Switch. HSRP Hello and Hold Time Intervals Hello interval time An HSRP-enabled Router sends hello messages to indicate that the Router is running and is capable of becoming either the active or the standby router. The interval between successive HSRP hello messages from a given HSRP Router. Default = 3 seconds. Hold interval time The interval between the receipt of a hello message and the assumption that the sending Router has failed. Default = 10 seconds. Timers in HSRP Router Active timer This timer is used to monitor the active Router. The timer resets any time a Router in the standby group receives a hello packet from the active Router. This timer expires in accordance with the hold time value that is set in the corresponding field of the HSRP hello message. Standby […]

What is the difference between HSRP and VRRP Protocols

HSRP Vs VRRP Comparison Table HSRP Protocol VRRP Protocol  Cisco Propietary IEEE Standards based and Open Standard RFC 2281 RFC 3768 Separate IP Address needed for the Virtual IP address in  HSRP Group Can use the Virtual IP Address of the VRRP Group as Physical IP address of any Router in VRRP group , if needed, saving IP space. One Master, all other routers are backup One Master, One Standby, all others are listening State More familiar to most network engineers Less familiar – yet very similar Can track an interface for failover Can track an interface for failover (depending on operating system and version) In HSRP Preempt disabled by default In VRRP preempt enabled by default In HSRP is maximum configurable priority on the Router is 255 In VRRP is maximum configurable priority on the Router is 254 In HSRP, there are equal priority Routers then the one which […]

Comparison and Difference between HSRP, VRRP and GLBP Protocols

In this article I covered comparison of various first hop redundancy protocols. HSRP, VRRP and GLBP are the main three first hop redundancy protocols. In order to take the right decision for your network you should know the basics regarding all three. The following chart provides difference HSRP Vs VRRP Vs GLBP protocols.                             Difference between HSRP, VRRP and GLBP Protocols Protocol Features HSRP VRRP GLBP Scope Cisco Proprietary IEEE standard Cisco proprietary Standard RFC2281 RFC3768 none OSI Layer Layer-3 Layer-3 Layer-2 Load Balancing No No Yes Multicast Group IP address 224.0.0.2 in version 1224.0.0.102 in version 2 224.0.0.18 224.0.0.102 Transport Port Number UDP 1985 UDP 112 UDP 3222 Timers Hello – 3 sec Advertisement – 1 sec Hello – 3sec Hold – 10 sec Master down time = 3*Advertisement Time + Skew TimeSkew Time = (256-            Priority)/256 […]

Cisco GLBP Load Balancing Options

CISCO GLBP LOAD BALANCING OPTIONS: Cisco Gateway Load Balancing Protocol (GLBP) is one of Cisco First Hop redundancy Protocols and it offers load balancing across multiple gateways. GLBP supports four types of load balancing options. How network hosts are assigned to each GLBP Router can be altered by using one of four load balancing options mentioned below. These options are not able to be deployed concurrently. There is a negligible CPU difference in the operation of either of these options. There are four different types of Load balancing algorithms in GLBP: 1. None 2. Host dependent 3. Weighted 4. Round robin NONE : If no load-balance algorithm is specified then GLBP will operate in an identical fashion to HSRP, the AVG will only respond to Address Resolution Protocol (ARP) requests with its own Virtual Forwarder (VF) MAC address, and all traffic will be directed to the AVG with no occurrence […]